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Speaker 1: I hear so many contradictory stats about DNA it makes

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Speaker 1: my head spin. I'm ninety nine percent similar to a chimp,

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Speaker 1: but only fifty percent similar to my fraternal twin black holes.

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Speaker 2: Both mass spin and charge so fine, Yet why not

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Speaker 2: color or weak charge in their design?

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Speaker 1: Yeah, Daniel, I think that your rhymes need to be

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Speaker 1: much longer so that people have trouble remembering what the

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Speaker 1: rhyme is supposed to be here. Check check out my

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Speaker 1: next one?

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Speaker 3: Ready?

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Speaker 1: Okay, Ugh, I have a high fever and I'm suffering

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Speaker 1: through the flu. Can I lower the fever with meds?

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Speaker 1: Or is the fever helping? What should I do? Longer's better, Daniel?

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Speaker 2: Probably more moaning is better.

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Speaker 1: Also, Yeah, that's right.

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Speaker 2: Whatever questions keep you up at night, Daniel and Kelly's

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Speaker 2: answers will bring your fever down and make it all right.

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Speaker 1: Welcome to Daniel and Kelly's extraordinary universe. This is Listener

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Speaker 1: Questions episode number thirty one.

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Speaker 2: Him Daniel, I'm a particle physicist, and I particularly love

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Speaker 2: to answer questions from everybody out there.

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Speaker 1: Hello. I'm Kelly Wainer Smith. I study parasites and space,

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Speaker 1: and I also love answering questions in part because it

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Speaker 1: helps me figure out what I actually didn't understand, because

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Speaker 1: nothing helps you understand something better than trying to explain

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Speaker 1: it to someone else.

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Speaker 2: I saw my daughter have that experience. I explained a

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Speaker 2: little bit of math to her last week, and then

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Speaker 2: she came home and said, hey, I explained this to

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Speaker 2: all my friends at lunch, and now I really understand it.

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Speaker 4: Oh nice.

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Speaker 1: And also how exciting that your daughter is explaining math

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Speaker 1: to her friends at lunch. That's a good sign.

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Speaker 2: Yeah, yeah, exactly. It's such a fun moment to see

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Speaker 2: her enjoying sharing these ideas and also to understand how

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Speaker 2: teaching something really is the best way to understand it.

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Speaker 2: Classes that I've taught as a professor are the ones

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Speaker 2: I understand the most deeply. In topics we've covered on

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Speaker 2: the podcast are things I understand much better than I

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Speaker 2: used to.

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Speaker 1: Yeah. Absolutely same. And whenever I see my daughter getting

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Speaker 1: excited and like trying to explain a concept to me

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Speaker 1: or to her friends, I always back off and I'm like,

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Speaker 1: a beautiful thing is happening. Just ruin it, Kelly by

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Speaker 1: trying to explain some extra stuff or trying to be like,

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Speaker 1: oh now, let's try to like, let's make a play

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Speaker 1: about this or something. It's like, back off because you

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Speaker 1: could ruin this. You're gonna ruin this, So I always

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Speaker 1: get nervous and then I try to not ruin the

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Speaker 1: beautiful thing.

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Speaker 2: But these listener Questions episodes are not just for me

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Speaker 2: and Kelly to understand things by explaining them. We think

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Speaker 2: that everybody else out there might also be curious about

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Speaker 2: the things these listeners wrote in about. So that's why

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Speaker 2: we share these questions with you, because we figure I

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Speaker 2: bet somebody else out there wants to hear this answer absolutely.

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Speaker 1: And let's start with Rob's question, which I'm guessing is

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Speaker 1: a question that a lot of people have had, and

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Speaker 1: I'm so glad that Rob went ahead and asked.

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Speaker 4: Hi, Daniel and Kelly, you guys do an extraordinary job

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Speaker 4: explaining this extraordinary universe that we live in. So I'm

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Speaker 4: hoping that you can explain something about genetics for me, please.

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Speaker 4: The question is this in the context of different species

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Speaker 4: and how closely related one is to another. I'll read

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Speaker 4: things like humans share ninety eight point seven percent of

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Speaker 4: DNA with bonobos, or we are four percent in the

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Speaker 4: undertal or fraternal twins share fifty percent of their DNA.

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Speaker 4: All of these statements seem mutually contradictory. How can we

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Speaker 4: share more DNA with bonobos, which, although our closest evolutionary relatives,

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Speaker 4: are nevertheless from a different genus than we share with

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Speaker 4: any human, let alone a sibling or another Homo species.

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Speaker 4: Thanks very much.

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Speaker 1: Doctor Nathan Lenz is a professor of biology at John

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Speaker 1: Jay College, City University of New York and the author

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Speaker 1: of multiple books, including The Sexual Evolution, How five hundred

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Speaker 1: million years of sex, gender, and mating shape modern relationships.

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Speaker 1: We chatted with Nathan about this book in our episode

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Speaker 1: from February twenty seventh, twenty twenty five. Be sure to

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Speaker 1: go back and check that out. We got loads of

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Speaker 1: nice comments about that episode, and you should check out

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Speaker 1: the book as well. Nathan has done research looking at

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Speaker 1: genomes of modern humans, African apes, Denise Evin's, and Neanderthals,

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Speaker 1: and were thrilled that he agreed to come on the

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Speaker 1: show to answer Rob's question. Welcome back, Nathan.

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Speaker 3: It's a pleasure to be here.

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Speaker 5: Thanks so much.

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Speaker 1: All right, So Rob's first question was human share ninety

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Speaker 1: eight point seven percent of DNA with bonobos? So let's

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Speaker 1: unpack that first. What does that mean?

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Speaker 3: Well, actually, I think the easier way to think about

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Speaker 3: this is to think about what you share with your siblings.

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Speaker 3: So the question came that you know, there's fifty percent

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Speaker 3: DNA from our siblings, and how is that so low

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Speaker 3: compared to sharing ninety seven percent with chimmithies. Let's start

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Speaker 3: with what you share with your siblings, so that measure

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Speaker 3: is actually a literal shared ancestry quantification. You literally have

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Speaker 3: fifty percent of the DNA from the same source as

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Speaker 3: your full sibling. So the reason why is you have

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Speaker 3: two of every chromosome. You have chromosome number one that

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Speaker 3: you got from your mother that is entirely derived from

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Speaker 3: your mother, and then chromosome number one from your father,

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Speaker 3: entirely derived from your father, and your sibling will have

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Speaker 3: the same but interesting, this is where it gets interesting,

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Speaker 3: they won't be the same ones, right, So, because remember

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Speaker 3: that your mother also had two chromosome number ones, one

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Speaker 3: from her mother and one from her father, your maternal grandparents,

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Speaker 3: and what she gave to you was not one or

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Speaker 3: the other, but a mixture of those two. Because we

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Speaker 3: break our chromosomes into chunks when we pass them on

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Speaker 3: to the next generation. So you will not pass your

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Speaker 3: intact chromosome number one, either one of them to your offspring.

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Speaker 3: It will be a combination of the material from the

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Speaker 3: two chromosome number ones that you have. And those chunks

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Speaker 3: are called segments. Chromosomes are broken up into either two, three,

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Speaker 3: or four segments every time they're passed on from one

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Speaker 3: generation to the next. So we can literally look at

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Speaker 3: the segments of all of your chromosomes and the segments

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Speaker 3: of all of your full siblings chromosomes, and fifty percent

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Speaker 3: roughly will be derived from the same source, so literally

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Speaker 3: from the same DNA. That's what we mean when we

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Speaker 3: say fifty percent for full siblings, twenty five percent for

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Speaker 3: half siblings, fifty percent from parents, and so on.

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Speaker 2: So let me clarify first. When you say fifty percent,

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Speaker 2: what exactly is the numerator and what exactly is the denominator?

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Speaker 2: Is the denominator the entire genome?

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Speaker 3: Right, The denominator is the entire genome, and the numerator

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Speaker 3: would be pieces of DNA of whatever size you want.

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Speaker 3: So you could look at one hundred base pairs of DNA,

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Speaker 3: you could look at a thousand, You could even look

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Speaker 3: at a million, and if you broke the DNA into

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Speaker 3: whatever segment size you want, you would be able to

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Speaker 3: derive fifty percent of them from one parent or the other.

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Speaker 3: And in fact, actually, if we had your grandparents' genomes

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Speaker 3: accessible to us, we could tell exactly which chunks are

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Speaker 3: which where the chromosomes were broken. We would need your grandparents'

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Speaker 3: genomes to do that, but if we did that, we

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Speaker 3: could actually tell exactly which chunks of which segments of

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Speaker 3: each chromosome came from which grandparent, and so on down.

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Speaker 2: I have another question, just to clarify and make sure

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Speaker 2: everybody's following along, because I'm not an expert in this either.

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Speaker 2: So I have two copies of every gene when it

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Speaker 2: comes from my mom, whe comes from my dad, but

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Speaker 2: my mom had two copies, so I get either A

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Speaker 2: or B version from her, and either A or B

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Speaker 2: version from my dad. And when you say fifty percent,

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Speaker 2: that's an average figure, right, Because there's a randomness there.

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Speaker 2: That could be that my brother and I have exactly

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Speaker 2: the same genome. That's very unlikely, but fifty percent is

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Speaker 2: the average.

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Speaker 3: Right, That's right, it's right. So is it possible to

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Speaker 3: have two siblings with exactly the same genomes without being

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Speaker 3: monozygotic twins. It is possible, but you're talking about something

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Speaker 3: that is in the order of trillions to one chances

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Speaker 3: even from this same times exactly heads every time, right,

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Speaker 3: exactly exactly. It's it's I don't know exactly how many

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Speaker 3: zeros zillion has, but it's it's an extremely large number

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Speaker 3: because remember chromosome number one. You know, it's twenty million

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Speaker 3: base pairs long. It can be cut anywhere along that

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Speaker 3: twenty It's not like there's it's you know, one half

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Speaker 3: or the other half. It can be cut one, two

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Speaker 3: or three times anywhere along its length. So it really

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Speaker 3: does get to be this astronomically large number of combinations.

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Speaker 2: So, but fifty percent is an average, and there must

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Speaker 2: be a distribution around that.

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Speaker 3: Yeah, it's a pretty tight distribution around fifty percent, because,

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Speaker 3: like I said, there's so many segments that we're talking about, right,

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Speaker 3: But thankfully, we actually have the same versions of most genes.

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Speaker 3: So that's why even though you might get some DNA

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Speaker 3: from one grandparent or the other, the odds of them

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Speaker 3: being importantly different, like different in any way that matters

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Speaker 3: to you or is actually pretty small because most of

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Speaker 3: us have all the same versions of all the same genes.

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Speaker 3: We actually differ very little in our genetic differences among us,

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Speaker 3: which is something that we're going to talk about in

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Speaker 3: a second. So if you imagine breaking these chromosomes into

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Speaker 3: all these segments each generation, you do that backwards in time,

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Speaker 3: what you will end up with by the time you

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Speaker 3: get to maybe eight or ten generations back. You've cut

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Speaker 3: the genome into such small pieces that there will be

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Speaker 3: some ancestors that you don't have any DNA from in

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Speaker 3: this literal sense, because it just got chopped up so

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Speaker 3: many times that none of their chunks actually ended up

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Speaker 3: in yours. So you might have an ancestor eight or

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Speaker 3: ten generations back that you got zero DNA from. They're

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Speaker 3: called genetic ghosts, and they start to appear, you know,

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Speaker 3: like I said, somewhere around ten generations back. And then

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Speaker 3: if you go another ten generations back, most of your

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Speaker 3: ancestors will be genetic ghosts, and they don't actually give

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Speaker 3: you any DNA because it is in these discrete segments.

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Speaker 2: So the discrete segments is important because it decreases the

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Speaker 2: number of options somebody has to contribute to you. Right,

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Speaker 2: if you have like zillions and zillions of base pairs.

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Speaker 2: That is very unlikely none of them are going to

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Speaker 2: come from an ancestor. But if you group them together,

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Speaker 2: then there's sort of fewer roles of the die and

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Speaker 2: it's more likely that somebody gets left out.

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Speaker 3: That's right, that's right. If we keep going back all

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Speaker 3: the way back to let's say the first human Neanderthal hybrid,

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Speaker 3: so this was an individual who had a Neanderthal mother

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Speaker 3: and more likely a human mother and a Neanderthal father.

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Speaker 3: We can talk about why that's more likely in a minute,

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Speaker 3: but a true.

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Speaker 2: Hybrid I definitely want to hear about why that's more likely.

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Speaker 3: Where half of the chromosomes all came from humans and

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Speaker 3: half all came from the anthos Well, remember we have

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Speaker 3: very similar genomes to Neanderthals, and so the chromosomes would

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Speaker 3: pair up and mix up just as if they were

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Speaker 3: from the same species. And when that happens, set the

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Speaker 3: entire Neanderthal chromosome number one keeps getting chopped up into

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Speaker 3: smaller and smaller pieces. And so now in the present

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Speaker 3: day we can only detect these small stretches of DNA

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Speaker 3: that come from Neanderthals. And the reason we know they

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Speaker 3: come from Neanderthals is because we've sequenced in the Neanderthal genome,

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Speaker 3: we've sequenced ancient human genomes, and we see these stretches

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Speaker 3: of little markers that we know came from Neanderthals because

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Speaker 3: of the order that they're in, because they haven't been

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Speaker 3: broken up yet. By the way, if we win another

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Speaker 3: one thousand generations, these pieces would probably be so broken

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Speaker 3: up that we might not even be able to tell

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Speaker 3: where they are. But right now we're at an interesting

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Speaker 3: point in human history where we can still detect that mixture.

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Speaker 3: And so you have these segments.

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Speaker 2: Well, then that's really fascinating because I guess it means

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Speaker 2: that the number of segments determines basically how many of

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Speaker 2: your ancestors can contribute, which is connected to basically how

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Speaker 2: far back in time you're getting contributions. So if you

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Speaker 2: go far enough back, then most of your ancestors are

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Speaker 2: genetic ghosts.

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Speaker 3: Right the are genetic ghosts, and the ones that are not,

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Speaker 3: they themselves are going to have have a complicated ancestry

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Speaker 3: with neanfols showing up many times in their family tree.

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Speaker 3: And when we say that the average human of European

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Speaker 3: ancestry has around three percent two to three percent in

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Speaker 3: the nthol DNA. It's important to remember that will be

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Speaker 3: different from person to person, So my two percent in

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Speaker 3: neandthol DNA will not necessarily be the same as yours.

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Speaker 3: In fact, it's unlikely to be the same. Something like

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Speaker 3: thirty or forty percent of the Neanderthal genome appears in

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Speaker 3: human genomes scattered all around, but obviously any one person

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Speaker 3: only has a small part of that. So we can

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Speaker 3: detect neanthol DNA almost everywhere in the genome in someone,

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Speaker 3: but in any one specific person, you're going to have

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Speaker 3: a tiny percentage of it. But we have we have

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Speaker 3: scattered bits of it all throughout the genome. So that's

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Speaker 3: what we mean when we say two to three percent

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Speaker 3: is there are segments still intact in many of us,

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Speaker 3: not all of us that we know because of the

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Speaker 3: order of the markers, they haven't been broken up yet

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Speaker 3: that they derive from Neanderthals.

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Speaker 1: Can we talk a little bit more about what we

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Speaker 1: mean about the order of the markers, because like I

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Speaker 1: would imagine that Neanderthal and humans we didn't diverge that

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Speaker 1: long ago or have a common ancestor that long ago.

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Speaker 1: How could we tell the difference between Neanderthal and human DNA.

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Speaker 3: It's a great question. Great question. So imagine a string

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Speaker 3: of Christmas lights that were all let's say a thousand

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Speaker 3: Christmas lights long, or let's be more, releasing a million

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Speaker 3: Christmas lights long. Well, all of us will have the

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Speaker 3: same color in most of the positions, so ninety nine

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Speaker 3: point nine percent we're all. Let's say, let's say that

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Speaker 3: the common color is black. We all have black, so

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Speaker 3: it would not be noticed. And then scattered are a

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Speaker 3: few blue lights and red lights, and green lights and

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Speaker 3: yellow lights and whatever. Well, there are segments, say of

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Speaker 3: a red here, and then a blue and then a

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Speaker 3: green in a precise order that we don't necessarily see

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Speaker 3: in most humans, but we know came from neanthols in

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Speaker 3: that order, and it hasn't been broken up yet. Now,

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Speaker 3: this is where things get probabilistic. So the law of

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Speaker 3: large numbers here works in our favor. But is it

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Speaker 3: possible that you could have ended up with those markers

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Speaker 3: and exactly the configuration that Neanderthals had just randomly? Yes,

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Speaker 3: it is possible, but that is such a small percentage

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Speaker 3: that we can effectively ignore it. The much more likely

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Speaker 3: scenario is that you inherited that chunk from an ancestor

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Speaker 3: in your deep past, a Neanderthal and ancestor in your

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Speaker 3: deep past. So it's the precise order of those markers,

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Speaker 3: and when they haven't yet been broken up by recombination

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Speaker 3: that shuffling process, then we know that they came from Neanderthals. Now, importantly,

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Speaker 3: most of these markers are actually not important, meaning they

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Speaker 3: don't code for anything. They're in non functional, non coding DNA,

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Speaker 3: because most of our DNA is non functional, non coding.

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Speaker 3: Most of these markers are therefore sort of irrelevant into

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Speaker 3: our physiology. But a couple of these, a couple very few,

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Speaker 3: are actually in important genes. And when that happens, that's

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Speaker 3: the really fascinating when we say that this version of

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Speaker 3: this gene was not human in origin, but Neanderthal Neanderthals

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Speaker 3: gave us this version of this gene, And that's where

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Speaker 3: things get really really interesting. But it's important to remember

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Speaker 3: that's a tiny, tiny part of the overall contribution of

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Speaker 3: Neanthals to our genome. Most of it is in the junk,

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Speaker 3: you know, littered with repetitive sequences and things like that.

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Speaker 2: Here's a nitpicky question. Is it possible that there's a

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Speaker 2: chunk which is identical between humans and Neanderthals and therefore indistinguishable,

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Speaker 2: and that my version of that did come from a

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Speaker 2: Neanderthal ancestor We just can't tell.

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Speaker 3: One hundred percent. That will definitely be the case because

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Speaker 3: most of the Neanofal genome is identical to the human genome, right,

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Speaker 3: and so those markers would look the same. There'd be

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Speaker 3: no way to determine their origin except if we looked

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Speaker 3: from generation to generation, so if we had a grandparent

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Speaker 3: and a parent, and then we could piece it together.

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Speaker 2: So when we say four percent, what is the numerator

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Speaker 2: and denominator there? It's still the full genome, but the

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Speaker 2: numerator is only the ones that we can distinguish between

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Speaker 2: the Enderthal and human.

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Speaker 3: That's right. It would be stretches of markers, so segments

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Speaker 3: of linked markers, so markers that are still linked together

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Speaker 3: that we can definitively identify as the enderthal in origin.

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Speaker 3: So is that an underestimate of what they contribute on average?

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Speaker 3: It's probably a good estimate on any individual. Then yeah,

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Speaker 3: it could be under or overcounting, right, But that's again

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Speaker 3: law of large numbers really works in our favor. You know.

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Speaker 3: It's one of these things where the odds of you

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Speaker 3: winning the lottery are very low, but the odds of

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Speaker 3: someone winning the lottery are very good. And that's what

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Speaker 3: we look at when we talk about thousands of generations

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Speaker 3: and lots of shuffling. If we look at enough people,

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Speaker 3: we'll be able to see the Neanderthal DNA.

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Speaker 2: I think this ghost ancestor thing is super fascinating. Can

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Speaker 2: you estimate how far back in time most of your

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Speaker 2: ancestors are ghosts by just doing like log based two

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Speaker 2: of the number of segments. Is it that simple?

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Speaker 5: Yeah?

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Speaker 3: So, I think I said it before about ten generations back,

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Speaker 3: or when the genetic ghosts start to appear, and another

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Speaker 3: ten generations from that is when the vast majority are

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Speaker 3: genetic ghosts.

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Speaker 2: Only twenty generations.

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Speaker 3: Yeah, it's not that long ago. If you the identical

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Speaker 3: ancestors point, which is what we call the point at

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Speaker 3: which we all share the exact same group of ancestors,

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Speaker 3: is really only a few thousand years ago. So a

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Speaker 3: few thousand years ago there are there are humans that

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Speaker 3: were the ancestors of all of us, and it was

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Speaker 3: a tiny minority of the ones that were alive at

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Speaker 3: that time. It's one of the things we've noticed about

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Speaker 3: population genetics is that it's really uneven. There are some

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Speaker 3: individuals that have billions of descendants and most individuals have

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Speaker 3: zero descendants. Reproduction is just really uneven.

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Speaker 2: So when they say that, you know, we're all descended

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Speaker 2: from gang his Cohn because he had so many children.

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Speaker 2: The fact that he had so many children doesn't guarantee

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Speaker 2: that andy of the genome is actually in us, does it?

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Speaker 3: Right? Except for the Y chromosome now, and then let's explain.

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Speaker 5: I'll get to y.

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Speaker 3: Y chromosome is a difference, but in the rest of

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Speaker 3: his genome. Yet, it's very unlikely that any of us

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Speaker 3: have Genghis cons DNA that literally inherited from him, unless

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Speaker 3: you're a male in Asia, and then you have a

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Speaker 3: pretty good chance of having his Y chromosome. And the

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Speaker 3: reason why the Y chromosome doesn't participate in this shuffle

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Speaker 3: a the Y chromosome is inherited intact from generation to generation.

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Speaker 3: The only thing that alters it is mutations, which do

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Speaker 3: appear randomly, and genghis cons. We actually know genghis CON's

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Speaker 3: y chromosome with a great deal of certainty because even

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Speaker 3: though his body was never found like it was, we

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Speaker 3: don't have his remains, but we know a y chromosome

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Speaker 3: that originated in Mongolia and then spread through Asia around

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Speaker 3: you know, eight hundred to one thousand years ago, and

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Speaker 3: that was because, of course, the Con as he was called,

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Speaker 3: went around his entire empire, leading his y chromosome everywhere

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Speaker 3: he went. Remember that his paternal grandson did the same thing,

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Speaker 3: Kubla Khan did the same thing. So you have the

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Speaker 3: same y chromosome being spread all around. And remember that

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Speaker 3: having ancestry from the Con made you a high station

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Speaker 3: in life. It was a status symbol in a lot

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Speaker 3: of these regions to have been a descendant. And so

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Speaker 3: they've therefore even greater likelihood that that y chromosome would

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Speaker 3: continue its prolific behavior. So we actually know his y

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Speaker 3: chromosome purely through deduction, because that's incredible. Yeah, And probably Charles,

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Speaker 3: Charles the Great Shark Charlemagne had a similar effect in Europe,

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Speaker 3: and most Europeans are descended from Charlemagne.

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Speaker 2: And is that connected to why you speculate about the

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Speaker 2: paternal and maternal origin of the first human Neanderthal hybrid.

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Speaker 3: Okay, so that's an interesting result just came out. So

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Speaker 3: when two species mix, right, you'll have all the same chromosomes,

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Speaker 3: all the same genes, but different versions and what But

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Speaker 3: that individual was going to be raised in one culture

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Speaker 3: or the other, right, So they almost certainly would have

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Speaker 3: been raised by the endithols if they had an NFL

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Speaker 3: mother and vice versa with.

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Speaker 2: A human mother.

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Speaker 3: What we've found is some genes actually don't operate as

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Speaker 3: well in the other genetic background. So we know that

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Speaker 3: there's a gene that's involved in heart function that that

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Speaker 3: we may very well have received from Neanderthals, But we

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Speaker 3: also know that our version in an otherwise Neanderthal heart

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Speaker 3: actually makes that heart perform not as well, so their

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Speaker 3: cardiac capacity goes down. So it might very well be

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Speaker 3: that some genes are not really well received by the

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Speaker 3: rest of the genetic background because of some kind of

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Speaker 3: interaction and then other versions, and so when Neanderthals and

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Speaker 3: humans intermixed, and we call that gene flow, natural selection

395
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Speaker 3: would have then continued and selected some versions of genes

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Speaker 3: as being better in one population or the other. And

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Speaker 3: there's no guarantee that you know that a neandothal gene

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Speaker 3: that works great in us would be with the opposite

399
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Speaker 3: would be true for the human version in their genetic background.

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Speaker 3: And so what we're finding is that in these moments

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Speaker 3: of hybridization, there was probably a lot of various selection

402
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Speaker 3: that happened within those versions of genes, and both species

403
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Speaker 3: probably benefited from the exchange by selecting the sort of

404
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Speaker 3: the good variant in the way that they lived and

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Speaker 3: eliminating bad variants again based on the way that they lived.

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Speaker 3: I thought there was.

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Speaker 1: Something interesting with the mitochondrial DNA going on. Am I misremembering?

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Speaker 6: No?

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Speaker 3: So no, you're you're exactly right. So mitochondrial DNA is

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Speaker 3: only inherited from the mother, so you can think of

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Speaker 3: it as similar to the Y chromosome inheritance as being

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Speaker 3: only from the paternal side. Mitochondrials only from the maternal

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Speaker 3: except for that all individuals have it, you know, we

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Speaker 3: don't have you know, it's not just a female only genetics,

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Speaker 3: but females are the only ones that pass it on.

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Speaker 3: And what we do know is that the mitochondrial genome

417
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Speaker 3: of the nfls did not come into the human gene pool.

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Speaker 3: So the gene pool of all modern humans is derived

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Speaker 3: from very ancient lineage of mitochondrial DNA that was not

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Speaker 3: affected by the Neanderthal introgression. And so what we think

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Speaker 3: that means is that the Neanderthal DNA that we do

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Speaker 3: have came from males, Neanderthal males into human females, and

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Speaker 3: the lineage proceeded that way, so that we absorbed the

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Speaker 3: genes from males. Now what happened on the opposite side,

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Speaker 3: we're not sure. We don't have enough genomes from Neanderthals,

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Speaker 3: but they seem to have their own distinct mitochondrial haplotypes,

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Speaker 3: which which we remember, will be similar to ours because

428
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Speaker 3: of course we share common ancestor with them about eight

429
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Speaker 3: hundred thousand years ago, so at one point we all

430
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Speaker 3: had the same mitochondrial type. But when they split, they

431
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Speaker 3: seem not to have intermixed after that. So we've had

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Speaker 3: a purely human version of the mitochondrial genome that was

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Speaker 3: not affected by Neanderthal interbreeding.

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Speaker 1: Fascinating, amazing. We are having weights much fun. So we

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Speaker 1: need to get to the last part of Rob's question.

436
00:23:02,680 --> 00:23:05,800
Speaker 1: And the last part of Rob's question is we share

437
00:23:05,880 --> 00:23:07,960
Speaker 1: something like ninety eight point seven percent of our DNA

438
00:23:08,000 --> 00:23:10,080
Speaker 1: with Bonobos. What does that mean?

439
00:23:10,440 --> 00:23:13,560
Speaker 3: So now this we can't do the segmental analysis at

440
00:23:13,600 --> 00:23:15,920
Speaker 3: all because by the time you get to seven million

441
00:23:16,000 --> 00:23:18,520
Speaker 3: years ago, which is when we have the common ancestor

442
00:23:18,600 --> 00:23:21,840
Speaker 3: with the two species of chimpanzees, then the segments have

443
00:23:21,880 --> 00:23:24,639
Speaker 3: all been obliterated, but the DNA is obviously still there.

444
00:23:24,680 --> 00:23:27,440
Speaker 3: So we have a common ancestry, but the chunks are

445
00:23:27,440 --> 00:23:30,040
Speaker 3: so small that we can't link up the markers and

446
00:23:30,080 --> 00:23:33,879
Speaker 3: look for stretches. So this kind of three percent Neanderthal

447
00:23:34,160 --> 00:23:36,160
Speaker 3: or fifty percent with your siblings, none of that would

448
00:23:36,200 --> 00:23:39,679
Speaker 3: apply when we're comparing chimpanzees to humans. What we do

449
00:23:39,800 --> 00:23:44,240
Speaker 3: instead is we do alignments. So we take the chromosomes

450
00:23:44,359 --> 00:23:47,159
Speaker 3: and segments of chromosomes and align them. And what we

451
00:23:47,200 --> 00:23:50,000
Speaker 3: do is we see how similar are the sequences. So

452
00:23:50,520 --> 00:23:53,480
Speaker 3: when we can align them very well, which is most

453
00:23:53,480 --> 00:23:56,080
Speaker 3: of the time, about eighty five percent of our DNA

454
00:23:56,119 --> 00:23:58,879
Speaker 3: lines up very very well with chimpanzees. When we line

455
00:23:58,880 --> 00:24:01,560
Speaker 3: it up, the sequence similar larity is around ninety eight

456
00:24:01,600 --> 00:24:06,520
Speaker 3: and a half percent, meaning it will be basically identical versions.

457
00:24:06,920 --> 00:24:09,000
Speaker 3: You know, ninety eight out of one hundred base pairs

458
00:24:09,040 --> 00:24:11,720
Speaker 3: will be exactly the same that's what we mean. Would

459
00:24:11,720 --> 00:24:14,320
Speaker 3: we say, so, it's more of a genetic similarity, not

460
00:24:14,600 --> 00:24:19,960
Speaker 3: necessarily strict inheritance. It's not shared inheritance, it's sequenced similarity.

461
00:24:20,000 --> 00:24:22,560
Speaker 3: And that's ninety eight point five percent. But that remember,

462
00:24:22,600 --> 00:24:26,520
Speaker 3: that's only within the segments that do align very well.

463
00:24:26,560 --> 00:24:30,080
Speaker 3: We have another thirteen to fifteen percent of our genome

464
00:24:30,200 --> 00:24:33,359
Speaker 3: that actually doesn't line up at all with chimpanzees in humans,

465
00:24:33,359 --> 00:24:36,600
Speaker 3: and that's because it's it's gobbledegook, right, it's it's been

466
00:24:37,440 --> 00:24:41,240
Speaker 3: invaded by parasitic DNA, by these repetitive elements that just

467
00:24:41,280 --> 00:24:45,440
Speaker 3: copy themselves. About nine percent of our genome is virus carcasses,

468
00:24:45,480 --> 00:24:48,200
Speaker 3: like the remains of virus infections, so that will be

469
00:24:48,240 --> 00:24:50,960
Speaker 3: different from lineags to lineag. Chimpanzees have their carcasses and

470
00:24:51,000 --> 00:24:54,000
Speaker 3: we have our carcasses. So when we say that it's

471
00:24:54,080 --> 00:24:57,439
Speaker 3: ninety eight percent similarity, that's that's just similarity in the

472
00:24:57,480 --> 00:25:00,240
Speaker 3: regions that we can align, which would have all the

473
00:25:00,280 --> 00:25:03,479
Speaker 3: genes in them, all the important stuff. The other regions

474
00:25:03,480 --> 00:25:05,600
Speaker 3: of the genome are much harder to align because they

475
00:25:05,640 --> 00:25:09,720
Speaker 3: are repetitive, so they get stuttered, they get broken, they invert,

476
00:25:10,280 --> 00:25:12,840
Speaker 3: they break off, and move to a different chromosome, that

477
00:25:12,920 --> 00:25:16,000
Speaker 3: kind of you know, we call that kind of gobbledygook

478
00:25:16,119 --> 00:25:19,879
Speaker 3: just because that DNA in almost all cases doesn't do anything.

479
00:25:19,920 --> 00:25:22,800
Speaker 3: It's not functional. It may be transcribed a little bit,

480
00:25:22,800 --> 00:25:25,719
Speaker 3: but it doesn't really do anything. And so and it's

481
00:25:25,760 --> 00:25:28,760
Speaker 3: impossible to really compare because you know, if you have,

482
00:25:29,640 --> 00:25:32,159
Speaker 3: you know, two puzzles that are made of different you know,

483
00:25:32,200 --> 00:25:34,920
Speaker 3: color pieces, they don't fit together. How similar are they?

484
00:25:35,040 --> 00:25:37,040
Speaker 3: You know, it doesn't really make any sense. But in

485
00:25:37,720 --> 00:25:40,040
Speaker 3: you know, about like I said, eighty five to eighty

486
00:25:40,080 --> 00:25:43,119
Speaker 3: seven percent of the genomes aligned very very well, and

487
00:25:43,200 --> 00:25:45,800
Speaker 3: their sequence similarity is around ninety eight and a half

488
00:25:45,800 --> 00:25:47,080
Speaker 3: percent something like that.

489
00:25:47,080 --> 00:25:48,040
Speaker 1: That answer was perfect.

490
00:25:48,080 --> 00:25:50,160
Speaker 3: Thank you so great, Thank you appreciate it.

491
00:25:50,240 --> 00:25:52,200
Speaker 1: All right, we're going to share this question with Rob

492
00:25:52,440 --> 00:25:54,240
Speaker 1: and see what he has to say.

493
00:25:54,640 --> 00:25:57,640
Speaker 4: Thank you so much, Kelly and Daniel, and especially thank

494
00:25:57,680 --> 00:26:01,480
Speaker 4: you to Nathan for that comprehensive, I'm clear answer. I

495
00:26:01,520 --> 00:26:05,000
Speaker 4: was particularly surprised by the revelation that, except for the

496
00:26:05,200 --> 00:26:08,199
Speaker 4: Y chromosome, we don't just get copy A of a

497
00:26:08,200 --> 00:26:11,320
Speaker 4: given chromosome from one parent and copy B from the other,

498
00:26:11,680 --> 00:26:15,480
Speaker 4: but take more of a genetic buffet approach. In hindsight,

499
00:26:15,560 --> 00:26:18,359
Speaker 4: I really regret only taking biology classes up to the

500
00:26:18,359 --> 00:26:21,159
Speaker 4: age of fourteen, which is about the worst time for

501
00:26:21,240 --> 00:26:24,000
Speaker 4: a boy to stop learning about biology. But as this

502
00:26:24,119 --> 00:26:25,919
Speaker 4: is a family show, that's all I'm going to say

503
00:26:25,960 --> 00:26:45,600
Speaker 4: on the matter. Thanks again, guys, keep being extraordinary.

504
00:26:49,119 --> 00:26:52,399
Speaker 2: Okay, we're back and we're answering questions from listeners, and

505
00:26:52,480 --> 00:26:55,560
Speaker 2: an ex comes from Abernite in London who has a

506
00:26:55,600 --> 00:26:57,560
Speaker 2: great question about black.

507
00:26:57,240 --> 00:27:02,040
Speaker 5: Holes hide of an eat from London. Thank you so

508
00:27:02,160 --> 00:27:04,760
Speaker 5: much for your podcast. It's really helped me reconnect with

509
00:27:04,800 --> 00:27:08,240
Speaker 5: topics I've always been curious about, but never seriously explode.

510
00:27:09,320 --> 00:27:12,280
Speaker 5: I had a question about black holes. We often hear

511
00:27:12,359 --> 00:27:15,479
Speaker 5: that black holes are completely described by just three things

512
00:27:16,040 --> 00:27:20,440
Speaker 5: their mass, spin, and electric charge. But I'm curious why

513
00:27:20,520 --> 00:27:23,359
Speaker 5: not color charge or weak charge as well? I asked,

514
00:27:23,359 --> 00:27:27,480
Speaker 5: since hawking radiation involves virtual particles, wouldn't that include quark

515
00:27:27,520 --> 00:27:31,560
Speaker 5: antiquark payers too, And if so, couldn't that give black

516
00:27:31,560 --> 00:27:34,560
Speaker 5: holes some kind of a color charge. Thank you again

517
00:27:34,720 --> 00:27:36,320
Speaker 5: and looking forward to your thoughts.

518
00:27:36,640 --> 00:27:40,720
Speaker 1: Oh right, Oh my gosh, okay, color charge. I gotta

519
00:27:40,760 --> 00:27:43,960
Speaker 1: be honest, I am still kind of confused about why

520
00:27:44,000 --> 00:27:47,280
Speaker 1: y'all decided to give a charge color. But you know,

521
00:27:47,480 --> 00:27:50,920
Speaker 1: actually that is a like a colorful thing you all did.

522
00:27:51,040 --> 00:27:53,520
Speaker 1: I dig that. I like when you all are whimsical,

523
00:27:54,320 --> 00:27:57,440
Speaker 1: like the charm quarks. That is a good name. I

524
00:27:57,560 --> 00:28:00,000
Speaker 1: like it. Maybe we should start with what our color charge?

525
00:28:00,440 --> 00:28:03,119
Speaker 2: Yeah? Good. So when we talk about charge, we usually

526
00:28:03,160 --> 00:28:05,480
Speaker 2: assume electric charge, and we're used to the idea of

527
00:28:05,480 --> 00:28:08,919
Speaker 2: electrons having minus one and protons having plus one and

528
00:28:08,960 --> 00:28:11,560
Speaker 2: all that good stuff. But we've talked on the podcast

529
00:28:11,600 --> 00:28:13,400
Speaker 2: a lot of times about how charge is a more

530
00:28:13,560 --> 00:28:17,840
Speaker 2: general concept. Electric charge is for the electromagnetic force, but

531
00:28:17,880 --> 00:28:20,919
Speaker 2: there are other forces out there, like the weak force,

532
00:28:21,040 --> 00:28:23,520
Speaker 2: and it has its own charges that tell you what

533
00:28:23,640 --> 00:28:25,639
Speaker 2: things pull on each other and what things push on

534
00:28:25,680 --> 00:28:29,480
Speaker 2: each other, etc. And there's the strong nuclear force, and

535
00:28:29,600 --> 00:28:33,320
Speaker 2: it has charges, and those charges we call color charges

536
00:28:33,400 --> 00:28:35,919
Speaker 2: because of the weird way that the strong force works.

537
00:28:36,160 --> 00:28:37,920
Speaker 2: You don't just have plus and minus. You have these

538
00:28:37,920 --> 00:28:42,280
Speaker 2: weird colors red, green, and blue. But the bottom line

539
00:28:42,440 --> 00:28:44,520
Speaker 2: is that some particles have some of these charges and

540
00:28:44,520 --> 00:28:48,520
Speaker 2: some particles don't. So, for example, an electron has electromagnetic

541
00:28:48,640 --> 00:28:50,840
Speaker 2: charge and it has a weak charge. It has no

542
00:28:51,000 --> 00:28:54,479
Speaker 2: color charge, so it doesn't feel the strong force, but

543
00:28:54,520 --> 00:28:57,280
Speaker 2: a quark has all of those charges, so it feels

544
00:28:57,320 --> 00:29:01,120
Speaker 2: every force. A neutrino has a weak charge, but no

545
00:29:01,200 --> 00:29:04,960
Speaker 2: color charge and no electromagnetic charge, so the charge tells

546
00:29:05,000 --> 00:29:07,160
Speaker 2: you which forces a particle feels.

547
00:29:08,080 --> 00:29:09,040
Speaker 1: Okay, got it.

548
00:29:09,880 --> 00:29:12,280
Speaker 2: And we often talk on the podcast about what black

549
00:29:12,320 --> 00:29:15,760
Speaker 2: holes can do. And black holes have this incredible ability

550
00:29:16,040 --> 00:29:20,480
Speaker 2: to hide whatever is behind their event horizon, and they're featureless.

551
00:29:20,520 --> 00:29:23,280
Speaker 2: There is no hair theorem that tells you that once

552
00:29:23,320 --> 00:29:25,640
Speaker 2: something goes beyond the event horizon, you can't tell anything

553
00:29:25,680 --> 00:29:27,040
Speaker 2: about what's inside.

554
00:29:27,640 --> 00:29:29,040
Speaker 1: Did you say a no hair?

555
00:29:29,600 --> 00:29:32,360
Speaker 2: Yes, a no hair theorem. That's exactly right.

556
00:29:32,440 --> 00:29:33,440
Speaker 1: Why no hair?

557
00:29:33,560 --> 00:29:35,800
Speaker 2: It's a way to say that black holes have no features,

558
00:29:36,360 --> 00:29:38,479
Speaker 2: Like if you have two black holes of the same mass,

559
00:29:38,560 --> 00:29:42,080
Speaker 2: they are exactly identical. There's no like hair on them

560
00:29:42,120 --> 00:29:45,239
Speaker 2: that tells you this one's different from that one. Or

561
00:29:45,320 --> 00:29:48,200
Speaker 2: you drop bananas into this one and apples into that one.

562
00:29:48,640 --> 00:29:50,920
Speaker 1: So it could have been a no nose or no

563
00:29:51,040 --> 00:29:54,560
Speaker 1: glasses theorem or whatever, but you guys.

564
00:29:54,560 --> 00:29:55,520
Speaker 2: Or no bonobos?

565
00:29:56,000 --> 00:29:57,440
Speaker 1: Yeah, so why no hair?

566
00:29:59,680 --> 00:30:02,320
Speaker 2: I think it's just physicists trying to be colorful and

567
00:30:02,520 --> 00:30:04,920
Speaker 2: you know, come up with the waves to envision this

568
00:30:04,960 --> 00:30:08,080
Speaker 2: stuff hair being like a texture. You know, there's no

569
00:30:08,320 --> 00:30:11,320
Speaker 2: amount of zooming in on the black hole you can

570
00:30:11,400 --> 00:30:17,760
Speaker 2: do to learn more about it and with the things. Hey, look,

571
00:30:17,760 --> 00:30:19,280
Speaker 2: we're trying to take ourselves seriously over here.

572
00:30:19,320 --> 00:30:20,960
Speaker 1: Okay.

573
00:30:23,000 --> 00:30:25,000
Speaker 2: But you can know some things about a black hole.

574
00:30:25,520 --> 00:30:27,840
Speaker 2: Like if you drop something into a black hole, it

575
00:30:27,840 --> 00:30:30,680
Speaker 2: becomes more massive, right, so you can know that there

576
00:30:30,720 --> 00:30:33,160
Speaker 2: is something inside the black hole. You can't know what

577
00:30:33,400 --> 00:30:35,800
Speaker 2: happened to it, or where is it on the inside,

578
00:30:36,120 --> 00:30:38,600
Speaker 2: what's going on beyond the event horizon. But you can

579
00:30:38,600 --> 00:30:41,720
Speaker 2: tell the difference between black holes that are big and small, right,

580
00:30:41,800 --> 00:30:45,120
Speaker 2: so you can measure their mass. You can also measure

581
00:30:45,160 --> 00:30:48,480
Speaker 2: their electric charge. Electric charge is conserved in the universe.

582
00:30:48,880 --> 00:30:50,880
Speaker 2: If I have a black hole that's neutral and then

583
00:30:50,920 --> 00:30:53,720
Speaker 2: I drop an electron into it, that black hole now

584
00:30:53,760 --> 00:30:56,360
Speaker 2: has a charge of minus one, so I can measure

585
00:30:56,440 --> 00:30:59,719
Speaker 2: that about a black hole. Also, angular momentum is conserved

586
00:30:59,720 --> 00:31:02,880
Speaker 2: in the universe. If I spin my black hole, then

587
00:31:03,000 --> 00:31:05,560
Speaker 2: I can tell that it's spinning. It has frame dragging

588
00:31:05,640 --> 00:31:08,600
Speaker 2: effects around it, So I can know the black hole's mass,

589
00:31:08,840 --> 00:31:10,760
Speaker 2: I can know the black hole spin, and I can

590
00:31:10,800 --> 00:31:13,320
Speaker 2: know the black hole's electric charge. That is what the

591
00:31:13,440 --> 00:31:16,080
Speaker 2: no harem theorem says that you can know those three

592
00:31:16,120 --> 00:31:18,960
Speaker 2: things about a black hole, and benit says, hold on

593
00:31:19,000 --> 00:31:21,680
Speaker 2: a second, if you have other kinds of charge, why

594
00:31:21,720 --> 00:31:25,040
Speaker 2: can't you tell if you've dropped those charges in no black.

595
00:31:24,760 --> 00:31:29,719
Speaker 1: Hole too, no harem theorem, no hair theorem?

596
00:31:28,960 --> 00:31:30,160
Speaker 4: You did?

597
00:31:30,240 --> 00:31:34,000
Speaker 1: Yeah, it was like, wow, that is one exciting black hole.

598
00:31:34,040 --> 00:31:35,840
Speaker 1: We know a lot about a black hole. It's got

599
00:31:35,880 --> 00:31:36,600
Speaker 1: a harem.

600
00:31:37,640 --> 00:31:39,120
Speaker 2: Well, I think if you have no hair, you probably

601
00:31:39,160 --> 00:31:42,240
Speaker 2: also have no harem. But these work out there.

602
00:31:43,240 --> 00:31:44,960
Speaker 1: There's a lot I want to say about that, but

603
00:31:45,040 --> 00:31:47,160
Speaker 1: this is a show that kids can listen to, So

604
00:31:47,280 --> 00:31:50,640
Speaker 1: let's move on. So why can't you see the color charges? Daniel?

605
00:31:51,160 --> 00:31:54,680
Speaker 2: Yeah, So first let's understand why you can see anything

606
00:31:54,800 --> 00:31:55,720
Speaker 2: about a black hole?

607
00:31:55,840 --> 00:31:55,959
Speaker 3: Right.

608
00:31:55,960 --> 00:31:58,920
Speaker 2: People sometimes wonder like, well, if the electron is inside

609
00:31:58,960 --> 00:32:01,520
Speaker 2: the event horizon, how do we know that it's there.

610
00:32:01,760 --> 00:32:06,760
Speaker 2: Isn't that communicating information outside of the black hole. So

611
00:32:06,840 --> 00:32:08,960
Speaker 2: let's be clear about what you can and can't know

612
00:32:09,080 --> 00:32:11,800
Speaker 2: about the black hole. Which you can't know is the

613
00:32:11,840 --> 00:32:16,240
Speaker 2: internal arrangements what's inside the event horizon, But you can

614
00:32:16,400 --> 00:32:20,160
Speaker 2: know the total charge. There's a theorem in physics called

615
00:32:20,240 --> 00:32:23,480
Speaker 2: Gauss's law that tells you that the total flux of

616
00:32:23,520 --> 00:32:27,000
Speaker 2: all the electromagnetic fields depends on the total enclosed charge,

617
00:32:27,120 --> 00:32:31,160
Speaker 2: whatever the arrangement is. And that also applies to black holes.

618
00:32:31,640 --> 00:32:34,520
Speaker 2: And so you can tell if there's a charge within

619
00:32:34,600 --> 00:32:37,720
Speaker 2: some volume of space just by measuring, like what is

620
00:32:37,720 --> 00:32:41,040
Speaker 2: the total flux of electromagnetic fields? So what you can't

621
00:32:41,080 --> 00:32:43,320
Speaker 2: know is like what happened to that charge? Where is

622
00:32:43,360 --> 00:32:45,920
Speaker 2: it inside the black hole? Didn't mutate to something else

623
00:32:45,960 --> 00:32:48,880
Speaker 2: with the same charge, But you can know that there

624
00:32:49,000 --> 00:32:51,360
Speaker 2: is a charge. And the way to think about it

625
00:32:51,400 --> 00:32:54,080
Speaker 2: is to say that charge is now applied to the

626
00:32:54,120 --> 00:32:58,480
Speaker 2: event horizon. Think of it like a membrane of charge

627
00:32:58,640 --> 00:33:02,240
Speaker 2: around the event horizon. Event horizon itself has a charge.

628
00:33:02,280 --> 00:33:04,520
Speaker 2: You don't know what's going on internally. That's what the

629
00:33:04,520 --> 00:33:06,600
Speaker 2: black hole is keeping hidden. But the fact that the

630
00:33:06,600 --> 00:33:09,480
Speaker 2: black hole itself is charged, think of as like a

631
00:33:09,560 --> 00:33:12,480
Speaker 2: charge on the whole event horizon, which is accessible to

632
00:33:12,520 --> 00:33:15,120
Speaker 2: you in the same way that like the event horizon's

633
00:33:15,240 --> 00:33:17,400
Speaker 2: mass is right, if you have a black hole out

634
00:33:17,440 --> 00:33:20,080
Speaker 2: in space, you can feel its mass. Even if you're

635
00:33:20,120 --> 00:33:23,280
Speaker 2: far away, you feel it's gravity. It's quite powerful even

636
00:33:23,320 --> 00:33:25,680
Speaker 2: from beyond the event horizon in the same way that

637
00:33:25,680 --> 00:33:28,880
Speaker 2: a black hole's mass can affect things beyond the event horizon.

638
00:33:29,240 --> 00:33:31,800
Speaker 2: So can the black holes charge even if you don't

639
00:33:31,800 --> 00:33:34,040
Speaker 2: know the internal configurations? Does that make sense?

640
00:33:34,280 --> 00:33:34,480
Speaker 3: Yeah?

641
00:33:34,480 --> 00:33:37,840
Speaker 1: But is this hypothetical or is this something we actually do?

642
00:33:37,840 --> 00:33:40,000
Speaker 1: Do we actually measure the charge of black holes?

643
00:33:40,360 --> 00:33:42,880
Speaker 2: We have never measured the charge of a black hole directly.

644
00:33:42,920 --> 00:33:46,240
Speaker 2: We do have some images of black holes and their

645
00:33:46,280 --> 00:33:50,120
Speaker 2: accretion disks, and those are consistent with black holes having

646
00:33:50,240 --> 00:33:54,120
Speaker 2: mass and spin and charge, But we haven't directly measured

647
00:33:54,280 --> 00:33:56,320
Speaker 2: the charge of a black hole by like dropping an

648
00:33:56,320 --> 00:33:59,440
Speaker 2: electron near it and seeing the effect or anything. So

649
00:33:59,440 --> 00:34:00,920
Speaker 2: in that sense, still theoretical.

650
00:34:01,320 --> 00:34:03,880
Speaker 1: Okay, so we know we can measure the electric charge.

651
00:34:04,240 --> 00:34:05,719
Speaker 1: We know we can measure the mass.

652
00:34:05,960 --> 00:34:07,320
Speaker 2: So what about a color charge?

653
00:34:07,400 --> 00:34:07,480
Speaker 7: Right?

654
00:34:07,600 --> 00:34:07,800
Speaker 1: Yeah?

655
00:34:07,800 --> 00:34:10,640
Speaker 2: What if you take the same thought experiment and instead

656
00:34:10,640 --> 00:34:13,080
Speaker 2: of dropping an electron into the black hole, you drop

657
00:34:13,120 --> 00:34:15,359
Speaker 2: a quark. A quark has a color charge to it.

658
00:34:15,760 --> 00:34:18,640
Speaker 2: Why doesn't that color charge spread across the membrane of

659
00:34:18,640 --> 00:34:19,320
Speaker 2: the black hole?

660
00:34:19,560 --> 00:34:20,120
Speaker 1: Yeah? Why not?

661
00:34:20,560 --> 00:34:23,080
Speaker 2: The reason is that you can't do that experiment. You

662
00:34:23,120 --> 00:34:26,840
Speaker 2: can't have free quarks, right, You can have a free electron,

663
00:34:27,120 --> 00:34:28,520
Speaker 2: you can hold on in your hand. It can be

664
00:34:28,560 --> 00:34:31,560
Speaker 2: floating in space. It's all cool. But quarks or anything

665
00:34:31,600 --> 00:34:34,360
Speaker 2: that has a color charge can't exist on its own

666
00:34:34,760 --> 00:34:38,840
Speaker 2: because the color force is so powerful that when you create,

667
00:34:38,880 --> 00:34:41,239
Speaker 2: for example, a cork and anti cork pair, they have

668
00:34:41,280 --> 00:34:44,000
Speaker 2: this very strong force between them. If you try to

669
00:34:44,040 --> 00:34:46,440
Speaker 2: pull them apart, so you get like an individual cork,

670
00:34:47,000 --> 00:34:49,760
Speaker 2: then the force actually gets stronger as they get further apart.

671
00:34:50,040 --> 00:34:53,560
Speaker 2: It's the opposite of like electricity or gravity. As things

672
00:34:53,600 --> 00:34:56,600
Speaker 2: get further apart, they get a stronger force. More energy

673
00:34:56,640 --> 00:35:00,000
Speaker 2: is now stored. It requires more energy to push them apart.

674
00:35:00,239 --> 00:35:03,480
Speaker 2: It becomes crazy high energetic. So much energy is stored

675
00:35:03,800 --> 00:35:07,040
Speaker 2: in that flux tube between them that that energy pops

676
00:35:07,080 --> 00:35:10,200
Speaker 2: out into new quarks, and so the universe does not

677
00:35:10,440 --> 00:35:13,320
Speaker 2: like to have quarks be that far apart. It'll create

678
00:35:13,400 --> 00:35:15,640
Speaker 2: more quarks and antiquarks in between them to keep them

679
00:35:15,640 --> 00:35:16,799
Speaker 2: from getting separated.

680
00:35:17,000 --> 00:35:17,920
Speaker 1: That's kind of cute.

681
00:35:18,080 --> 00:35:20,120
Speaker 2: Yeah, it's amazing. That's when we see this all the time.

682
00:35:20,160 --> 00:35:23,359
Speaker 2: In the large Hadron collider, we create quarks and antiquarks.

683
00:35:23,520 --> 00:35:25,839
Speaker 2: They're shooting a part at super high speed, and then

684
00:35:25,920 --> 00:35:28,080
Speaker 2: out of the vacuum pop additional quarks and we can

685
00:35:28,080 --> 00:35:31,160
Speaker 2: get these jets of particles sprays the particles instead of

686
00:35:31,200 --> 00:35:32,160
Speaker 2: individual quarks.

687
00:35:32,280 --> 00:35:34,240
Speaker 1: Where do they Where do they come from?

688
00:35:34,360 --> 00:35:36,680
Speaker 2: Well, their mass just comes from the energy, right. You

689
00:35:36,760 --> 00:35:39,040
Speaker 2: have to have enough energy to push these things apart,

690
00:35:39,320 --> 00:35:41,279
Speaker 2: and then that energy gets turned into a mass of

691
00:35:41,320 --> 00:35:43,919
Speaker 2: new quarks. So you can't do this experiment. You can't

692
00:35:44,040 --> 00:35:46,319
Speaker 2: drop a free quark into a black hole because there

693
00:35:46,360 --> 00:35:49,680
Speaker 2: are no free quarks all right, So that feels a

694
00:35:49,680 --> 00:35:52,560
Speaker 2: little bit like an evasion. Right, I've avoided the question

695
00:35:53,200 --> 00:35:56,920
Speaker 2: what about the weak charges? Right, because you can have neutrinos.

696
00:35:57,000 --> 00:35:59,880
Speaker 2: Neutrinos have a weak charge and they have no color charge,

697
00:36:00,040 --> 00:36:03,200
Speaker 2: and you can have individual neutrinos out in space. So

698
00:36:03,400 --> 00:36:05,759
Speaker 2: what happens if you drop a weak charge into a

699
00:36:05,800 --> 00:36:06,360
Speaker 2: black hole?

700
00:36:06,800 --> 00:36:09,680
Speaker 1: I don't know. Why would you ask me, Daniel?

701
00:36:11,520 --> 00:36:13,280
Speaker 2: It was a rhetorical set up for myself.

702
00:36:13,280 --> 00:36:14,560
Speaker 1: Oh got it, got it, okay?

703
00:36:15,680 --> 00:36:18,640
Speaker 2: And so weak charge is fundamentally different from electric charge.

704
00:36:18,680 --> 00:36:22,080
Speaker 2: Electric charge is conserved in the universe. There is a

705
00:36:22,160 --> 00:36:24,719
Speaker 2: symmetry of the action. If you remember the episode we

706
00:36:24,800 --> 00:36:29,400
Speaker 2: just did about action that via notother's theorem, enforces conservation

707
00:36:29,440 --> 00:36:33,640
Speaker 2: of electric charge absolutely in the universe, totally conserved week

708
00:36:33,719 --> 00:36:36,640
Speaker 2: charge does not have the same symmetry, so there is

709
00:36:36,719 --> 00:36:39,319
Speaker 2: no conservation law for a week charge. So it's not

710
00:36:39,480 --> 00:36:42,000
Speaker 2: like if you drop a neutrino into a black hole,

711
00:36:42,280 --> 00:36:44,719
Speaker 2: it has to keep that weak charge. It can morph

712
00:36:44,840 --> 00:36:49,800
Speaker 2: into something else. Also, weak charges are short range forces,

713
00:36:50,280 --> 00:36:54,120
Speaker 2: so the electromagnetic force is communicated by photons. These have

714
00:36:54,280 --> 00:36:57,600
Speaker 2: infinite range, Like if you have an electron across the universe,

715
00:36:57,920 --> 00:37:01,040
Speaker 2: you can in principle feel that it's there because the

716
00:37:01,040 --> 00:37:04,719
Speaker 2: electromagnetic force has an infinite range. The weak force, because

717
00:37:04,719 --> 00:37:07,800
Speaker 2: it's communicated by massive bosons like the W and the

718
00:37:07,880 --> 00:37:10,879
Speaker 2: Z instead of the mass lists photon, is a very

719
00:37:10,960 --> 00:37:14,400
Speaker 2: weak range force. And you might be wondering, like, all right,

720
00:37:14,440 --> 00:37:16,440
Speaker 2: but if I drop a neutrino into a black hole

721
00:37:16,600 --> 00:37:19,360
Speaker 2: and then I'm like really near the black hole, couldn't

722
00:37:19,360 --> 00:37:22,120
Speaker 2: I still somehow tell that there was a neutrino dropped

723
00:37:22,120 --> 00:37:24,840
Speaker 2: into there, even if it's a short range force. And

724
00:37:24,920 --> 00:37:26,839
Speaker 2: here we have to clarify exactly what the no hair

725
00:37:26,960 --> 00:37:31,240
Speaker 2: theorem says. It's often said, Okay, you can measure the charge,

726
00:37:31,320 --> 00:37:33,200
Speaker 2: the mass and the spin of the black hole and

727
00:37:33,239 --> 00:37:36,120
Speaker 2: that's it. But really it says that you can only

728
00:37:36,200 --> 00:37:38,520
Speaker 2: measure the mass, the charge, and the spin of a

729
00:37:38,560 --> 00:37:42,680
Speaker 2: black hole from very far away and over time. So

730
00:37:42,719 --> 00:37:45,600
Speaker 2: these are the only long term things you can measure

731
00:37:45,640 --> 00:37:49,360
Speaker 2: from very far away. Black Holes can have other properties

732
00:37:49,560 --> 00:37:53,360
Speaker 2: short term, like, for example, if two black holes merge,

733
00:37:53,760 --> 00:37:57,359
Speaker 2: their event horizons are not spherical briefly, so you can

734
00:37:57,400 --> 00:38:00,680
Speaker 2: tell something about the internal arrangement or the history. Eventually

735
00:38:00,719 --> 00:38:04,520
Speaker 2: it settles down into a nice symmetrical spherical shape. That's

736
00:38:04,560 --> 00:38:06,080
Speaker 2: where the long hair theorem applies.

737
00:38:06,200 --> 00:38:11,080
Speaker 1: The long hair theorem.

738
00:38:11,160 --> 00:38:13,080
Speaker 2: I'm going to give this theorem like ten different names

739
00:38:13,080 --> 00:38:17,600
Speaker 2: before we're done, the long hairm theorem, the no hair theorem.

740
00:38:17,960 --> 00:38:20,280
Speaker 2: So the no hair theorem says that for a black

741
00:38:20,280 --> 00:38:23,560
Speaker 2: hole that's had chance to stabilize, the things you can

742
00:38:23,640 --> 00:38:29,480
Speaker 2: measure from very far away, essentially from infinity, are mass, charge,

743
00:38:30,040 --> 00:38:33,279
Speaker 2: and spin. But for a black hole that recently you

744
00:38:33,360 --> 00:38:35,719
Speaker 2: dropped a neutrino into it, if you're very near it,

745
00:38:35,800 --> 00:38:38,520
Speaker 2: you could tell that a neutrino got dropped into it.

746
00:38:39,080 --> 00:38:42,200
Speaker 2: So that's consistent with the long hair theorem. If you.

747
00:38:45,160 --> 00:38:48,720
Speaker 1: That's consistent with the mohawk theorem. Let's keep going.

748
00:38:49,880 --> 00:38:52,360
Speaker 2: That's consistent with the no hair theorem. I'm going to

749
00:38:52,400 --> 00:38:55,400
Speaker 2: get it right once as long as you spell it

750
00:38:55,520 --> 00:38:58,840
Speaker 2: exactly what the no hair theorem says right, which includes

751
00:38:58,840 --> 00:39:01,319
Speaker 2: those caveats that it's after the black hole has had

752
00:39:01,360 --> 00:39:04,279
Speaker 2: a chance to settle and your observer is far from

753
00:39:04,280 --> 00:39:04,960
Speaker 2: the black hole.

754
00:39:05,120 --> 00:39:07,960
Speaker 1: So Abony was right that you can measure the weak

755
00:39:08,040 --> 00:39:10,640
Speaker 1: charge in a black hole under the right condition.

756
00:39:11,040 --> 00:39:13,839
Speaker 2: You can measure the weak charge of a black hole

757
00:39:13,960 --> 00:39:17,160
Speaker 2: if you're near it soon enough after neutrino was dropped in.

758
00:39:17,200 --> 00:39:19,600
Speaker 2: You're not guaranteed that weak charge it's going to persist,

759
00:39:19,840 --> 00:39:21,600
Speaker 2: or that you can measure it from far away, So

760
00:39:21,640 --> 00:39:25,240
Speaker 2: that doesn't violate the Kelly's hair theorem of black holes.

761
00:39:26,640 --> 00:39:29,320
Speaker 1: I like mohawks. I think it should be the mohawk theorem.

762
00:39:29,520 --> 00:39:31,880
Speaker 2: And the last part of his question was about hawking radiation,

763
00:39:32,320 --> 00:39:35,000
Speaker 2: which is often told as this story of particles and

764
00:39:35,000 --> 00:39:38,640
Speaker 2: antiparticles popping out of the vacuum near the event horizon

765
00:39:38,680 --> 00:39:41,120
Speaker 2: and one falling in and one not, and the one

766
00:39:41,120 --> 00:39:43,480
Speaker 2: that doesn't fall in is the hawking radiation. That is

767
00:39:43,600 --> 00:39:48,280
Speaker 2: not hawking radiation. That is a cartoon picture in popular science,

768
00:39:48,280 --> 00:39:52,520
Speaker 2: which does not reflect what actually happens to generate hawking radiation.

769
00:39:53,200 --> 00:39:55,759
Speaker 2: We don't know what actually happens because we don't have

770
00:39:55,800 --> 00:39:58,399
Speaker 2: a theory of how gravity works for particles. That would

771
00:39:58,440 --> 00:40:02,600
Speaker 2: require a theory of quantum gravity. And Hawking radiation is

772
00:40:02,640 --> 00:40:06,680
Speaker 2: a semi classical approximation that says when you have an

773
00:40:06,719 --> 00:40:09,880
Speaker 2: event horizon near a quantum field, there will be some radiation,

774
00:40:10,320 --> 00:40:14,160
Speaker 2: but there's no accurate particle picture. This hand wavy story

775
00:40:14,200 --> 00:40:18,000
Speaker 2: about particles and antiparticles is very misleading. Actually, Hawking is

776
00:40:18,040 --> 00:40:20,000
Speaker 2: the one who came up with it in one of

777
00:40:20,040 --> 00:40:23,160
Speaker 2: his popular science books, and he acknowledges that it's not

778
00:40:23,200 --> 00:40:26,240
Speaker 2: accurate and may be misleading. And it's just like pervaded

779
00:40:26,400 --> 00:40:30,320
Speaker 2: all of popular science and leads people astray in exactly

780
00:40:30,480 --> 00:40:33,040
Speaker 2: this way. So discard. If you can the picture of

781
00:40:33,080 --> 00:40:35,800
Speaker 2: Hawking radiation from your mind, it won't teach you anything

782
00:40:35,840 --> 00:40:37,000
Speaker 2: about what actually happens.

783
00:40:37,200 --> 00:40:41,720
Speaker 1: I detect a touch of frustration in your voice.

784
00:40:42,480 --> 00:40:44,240
Speaker 2: That's the Daniel's pulling his hair out theorem.

785
00:40:44,640 --> 00:40:46,480
Speaker 1: Oh yeah, I think we should call it the bad

786
00:40:46,520 --> 00:40:47,600
Speaker 1: hair Days here go.

787
00:40:48,160 --> 00:40:51,920
Speaker 2: Okay, all right, let's send that answer off to Abernit

788
00:40:52,040 --> 00:40:53,800
Speaker 2: and see if it answers his question.

789
00:40:54,280 --> 00:40:57,920
Speaker 6: Thank you so much, Darlike for answering my question. The

790
00:40:58,000 --> 00:41:01,200
Speaker 6: explanation really made sense. It was great to get a

791
00:41:01,239 --> 00:41:04,120
Speaker 6: clearer understanding of what the no head theorem actually says

792
00:41:04,600 --> 00:41:07,480
Speaker 6: and why properties like color and weak charge can't show

793
00:41:07,480 --> 00:41:10,759
Speaker 6: off a black holes in any observable way. I also

794
00:41:10,800 --> 00:41:14,920
Speaker 6: really appreciated the clarification around Hawking radiation. It's always helpful

795
00:41:14,920 --> 00:41:17,040
Speaker 6: to unlearn some of the pop science imagery we pick

796
00:41:17,120 --> 00:41:19,800
Speaker 6: up along the way, and it definitely made me wonder

797
00:41:19,880 --> 00:41:23,080
Speaker 6: what other common misconceptions are still floating around, like the

798
00:41:23,120 --> 00:41:25,959
Speaker 6: one with the Higgs feel for example. Maybe that's something

799
00:41:26,040 --> 00:41:29,239
Speaker 6: we'll hear more about in the future episodes. Thanks again

800
00:41:29,239 --> 00:41:30,440
Speaker 6: for such a thoughtful discussion.

801
00:41:30,640 --> 00:41:31,640
Speaker 5: I really enjoyed it.

802
00:41:51,320 --> 00:41:51,640
Speaker 3: All right.

803
00:41:51,719 --> 00:41:55,040
Speaker 1: Our last question of the day is from Gordon, who

804
00:41:55,239 --> 00:41:58,360
Speaker 1: hopefully is over his flu by now. Let's go ahead

805
00:41:58,400 --> 00:41:59,320
Speaker 1: and listen to the question.

806
00:42:00,080 --> 00:42:01,000
Speaker 2: Hi, Daniel and Kelly.

807
00:42:01,320 --> 00:42:03,319
Speaker 7: As I'm recovering from the flu, I was wondering about

808
00:42:03,320 --> 00:42:05,319
Speaker 7: the various symptoms and treatments we tend to use for

809
00:42:05,400 --> 00:42:09,040
Speaker 7: certain incurable diseases that we can't treat directly. As I

810
00:42:09,120 --> 00:42:11,680
Speaker 7: understand it, some symptoms like a fever our ways our

811
00:42:11,719 --> 00:42:14,680
Speaker 7: immune system is trying to combat the disease. In that case,

812
00:42:14,719 --> 00:42:17,279
Speaker 7: trying to kill the infection by cooking it. Of course,

813
00:42:17,280 --> 00:42:19,680
Speaker 7: we find this very uncomfortable and so often try to

814
00:42:19,719 --> 00:42:22,839
Speaker 7: relieve such symptoms like trying to cool ourselves down. So

815
00:42:22,880 --> 00:42:25,040
Speaker 7: my question is how much do our attempts to relieve

816
00:42:25,080 --> 00:42:27,960
Speaker 7: the various symptoms actually hinder our bodies natural mechanisms for

817
00:42:28,000 --> 00:42:30,320
Speaker 7: fighting the diseases. Would we be better off in the

818
00:42:30,320 --> 00:42:32,520
Speaker 7: long run just bearing with the discomfort and allowing it

819
00:42:32,560 --> 00:42:35,200
Speaker 7: to fully run its course, or even possibly amplifying the

820
00:42:35,200 --> 00:42:37,920
Speaker 7: effects if it could be done safely. Thank you so much.

821
00:42:38,000 --> 00:42:40,920
Speaker 7: Love the podcast. Ooh, this is so fun because I

822
00:42:41,000 --> 00:42:44,959
Speaker 7: also have this question. I'm often wondering if the tile

823
00:42:45,000 --> 00:42:47,120
Speaker 7: in all or advil I'm taking to lower my fever

824
00:42:47,600 --> 00:42:49,600
Speaker 7: is making me feel better at the expense of my

825
00:42:49,680 --> 00:42:53,279
Speaker 7: body's ability to fight this infection. So Kelly, who is

826
00:42:53,320 --> 00:42:55,560
Speaker 7: not a doctor, give me some medical advice.

827
00:42:55,840 --> 00:42:59,400
Speaker 1: Thank you for reminding everybody that I'm not a medical doctor.

828
00:43:01,400 --> 00:43:04,720
Speaker 1: But yes, okay. First, I want to clarify that fevers

829
00:43:04,760 --> 00:43:08,439
Speaker 1: are different than hyperthermia, which is heat stroke. So when

830
00:43:08,440 --> 00:43:11,120
Speaker 1: you have heat stroke you should always try to lower

831
00:43:11,160 --> 00:43:17,080
Speaker 1: your body temperature, but fevers are actually this evolutionarily ancient

832
00:43:17,200 --> 00:43:20,839
Speaker 1: strategy for fighting infections. And so there's this field called

833
00:43:20,920 --> 00:43:25,000
Speaker 1: evolutionary medicine where people study the way our bodies respond

834
00:43:25,000 --> 00:43:28,359
Speaker 1: to infection by looking at the way you know, other

835
00:43:28,480 --> 00:43:32,120
Speaker 1: bodies have responded to infection over evolutionary history. So it

836
00:43:32,120 --> 00:43:35,720
Speaker 1: turns out that birds and other mammals will get fevers

837
00:43:35,760 --> 00:43:39,160
Speaker 1: when they're sick, and animals like lizards and insects, when

838
00:43:39,160 --> 00:43:43,399
Speaker 1: they get infections, will generate fevers by sitting under the sun.

839
00:43:43,480 --> 00:43:45,200
Speaker 1: So these are animals that are you know, what we'd

840
00:43:45,239 --> 00:43:48,799
Speaker 1: call ectotherms. They can't generate their own body heat, and

841
00:43:48,840 --> 00:43:51,080
Speaker 1: so in order to raise their body temperature, they need

842
00:43:51,120 --> 00:43:53,920
Speaker 1: to do things like lay on warm rocks under the

843
00:43:53,960 --> 00:43:56,880
Speaker 1: sun to raise their body temperatures. And the idea here

844
00:43:57,040 --> 00:44:00,719
Speaker 1: is that pathogens don't do as well under high temperatures,

845
00:44:00,719 --> 00:44:03,239
Speaker 1: and so they are raising their body temperatures to try

846
00:44:03,239 --> 00:44:04,279
Speaker 1: to kill the pathogens.

847
00:44:04,680 --> 00:44:09,320
Speaker 2: So why are pathogens more sensitive to temperature than our cells.

848
00:44:09,719 --> 00:44:12,400
Speaker 1: So there's a couple different hypotheses for what's happening here.

849
00:44:12,480 --> 00:44:17,320
Speaker 1: So one idea is that our immune cells work better

850
00:44:17,400 --> 00:44:20,400
Speaker 1: at higher temperatures, and so there have been sun studies

851
00:44:20,400 --> 00:44:24,600
Speaker 1: showing that certain immune cells, like phagocytes, So these are

852
00:44:24,640 --> 00:44:30,080
Speaker 1: cells that essentially engulf pathogens and like eat them do

853
00:44:30,239 --> 00:44:34,680
Speaker 1: better work under high temperatures, and so those cells would

854
00:44:34,680 --> 00:44:38,040
Speaker 1: just be better at their jobs when your body is hotter.

855
00:44:38,560 --> 00:44:42,560
Speaker 1: And then the other idea is that rapidly dividing pathogens

856
00:44:43,120 --> 00:44:46,440
Speaker 1: are more likely to die or have trouble dividing, and

857
00:44:46,600 --> 00:44:49,879
Speaker 1: the cells that they might infect would be more likely

858
00:44:49,920 --> 00:44:52,759
Speaker 1: to die when those temperatures are high. And while you

859
00:44:52,800 --> 00:44:55,239
Speaker 1: don't want your own cells to be dying, if those

860
00:44:55,239 --> 00:44:57,319
Speaker 1: cells are infected by a virus, you might be willing

861
00:44:57,360 --> 00:45:00,560
Speaker 1: to sacrifice them to your high temperature. It kills the

862
00:45:00,560 --> 00:45:03,279
Speaker 1: pathogens as well. And so those are the two of

863
00:45:03,280 --> 00:45:07,040
Speaker 1: the current hypotheses for why high temperatures are worse for

864
00:45:07,160 --> 00:45:09,759
Speaker 1: pathogens than they are for you. And to be clear,

865
00:45:09,840 --> 00:45:12,680
Speaker 1: the idea isn't that the high fevers don't harm you

866
00:45:12,880 --> 00:45:15,640
Speaker 1: at all. The idea is that the high fevers are

867
00:45:15,680 --> 00:45:17,600
Speaker 1: worse for the pathogens than they are.

868
00:45:17,440 --> 00:45:19,879
Speaker 2: For you, because they're pretty bad for me. I mean,

869
00:45:20,200 --> 00:45:22,000
Speaker 2: I am miserable when I have a fever. That you're

870
00:45:22,000 --> 00:45:25,320
Speaker 2: like aky in general, just feeling achy everywhere.

871
00:45:25,560 --> 00:45:28,239
Speaker 1: Yeah, I get that. There have been some studies where

872
00:45:28,280 --> 00:45:32,360
Speaker 1: they found that people who mount high fevers tend to

873
00:45:32,440 --> 00:45:36,080
Speaker 1: recover quickly, and for certain kinds of diseases, are less

874
00:45:36,160 --> 00:45:39,160
Speaker 1: likely to die if they mount a high fever. The

875
00:45:39,239 --> 00:45:43,360
Speaker 1: problem is those are observational studies, and an observational study

876
00:45:43,440 --> 00:45:45,920
Speaker 1: might just be telling you that somebody who mounts a

877
00:45:46,000 --> 00:45:48,520
Speaker 1: high fever just in general, has a body that's doing

878
00:45:48,520 --> 00:45:52,480
Speaker 1: a better job at going all out attacking an invader.

879
00:45:53,120 --> 00:45:55,799
Speaker 1: There have also been some experimental studies where they've done

880
00:45:55,840 --> 00:45:59,880
Speaker 1: things like randomly picked individuals who come into the er

881
00:46:00,200 --> 00:46:02,680
Speaker 1: to put in a bed that's meant to cool their

882
00:46:02,719 --> 00:46:05,839
Speaker 1: whole body down, and some of those studies have had

883
00:46:05,840 --> 00:46:08,120
Speaker 1: to be shut down because it was clear that cooling

884
00:46:08,200 --> 00:46:12,040
Speaker 1: people's bodies down was not helping, and that the fevers

885
00:46:12,040 --> 00:46:13,960
Speaker 1: seem to be part of the way that, you know,

886
00:46:14,000 --> 00:46:17,799
Speaker 1: the body was proactively responding to an infection. So there

887
00:46:17,880 --> 00:46:21,080
Speaker 1: is some good experimental evidence that fevers are part of

888
00:46:21,120 --> 00:46:26,640
Speaker 1: how our body is proactively responding, and so evolutionary medicine

889
00:46:26,920 --> 00:46:30,560
Speaker 1: folks would say, you know, bodies of all types have

890
00:46:30,640 --> 00:46:33,120
Speaker 1: been doing this for millions of years as our way

891
00:46:33,120 --> 00:46:36,640
Speaker 1: of responding to infection. You know, let's go ahead and

892
00:46:37,239 --> 00:46:39,160
Speaker 1: believe that in a lot of cases this is good.

893
00:46:39,280 --> 00:46:42,600
Speaker 1: But it is worth noting that again, this strategy is

894
00:46:42,640 --> 00:46:45,239
Speaker 1: accepting that it is also bad for the host, but

895
00:46:45,320 --> 00:46:47,480
Speaker 1: it's hopefully going to be worse for the pathogen. But

896
00:46:48,239 --> 00:46:51,359
Speaker 1: when you, for example, are pregnant or when you are

897
00:46:51,600 --> 00:46:55,640
Speaker 1: very elderly, this becomes a riskier strategy because you are

898
00:46:55,760 --> 00:46:59,600
Speaker 1: compromised in a variety of ways, and so this risky

899
00:46:59,600 --> 00:47:04,000
Speaker 1: stratategy might not play out in your favor under these conditions.

900
00:47:04,000 --> 00:47:06,759
Speaker 1: And in general, you know you should go to a

901
00:47:06,800 --> 00:47:09,120
Speaker 1: doctor if you are feeling particularly crummy.

902
00:47:09,400 --> 00:47:13,240
Speaker 2: Fevers are terrifying. Also, our son Silas had a shockingly

903
00:47:13,320 --> 00:47:16,440
Speaker 2: high fever recently to do an infection, and as a

904
00:47:16,480 --> 00:47:19,320
Speaker 2: parent should like, oh my god, that numbered terre of us.

905
00:47:19,400 --> 00:47:22,200
Speaker 1: Yeah. Yeah, And so when you get a shockingly high

906
00:47:22,239 --> 00:47:24,640
Speaker 1: fever and you're worried, you should always call a doctor

907
00:47:24,800 --> 00:47:27,239
Speaker 1: or bring your kiddo into the hospital. You should probably

908
00:47:27,280 --> 00:47:30,080
Speaker 1: call the doctor first. But I was going through a

909
00:47:30,120 --> 00:47:32,840
Speaker 1: bunch of websites like the Texas Children's Hospital and stuff

910
00:47:32,880 --> 00:47:35,359
Speaker 1: like that, looking to see at what point should you

911
00:47:35,440 --> 00:47:38,600
Speaker 1: start giving your kiddo medication for bringing their fever down,

912
00:47:39,120 --> 00:47:41,920
Speaker 1: And the advice is much different than what I remember,

913
00:47:41,960 --> 00:47:44,000
Speaker 1: the advice being that my mom got because when my

914
00:47:44,040 --> 00:47:45,720
Speaker 1: brother got a high fever when he was a kid,

915
00:47:46,080 --> 00:47:49,479
Speaker 1: they dumped him in a container of ice water wow

916
00:47:49,719 --> 00:47:52,840
Speaker 1: to bring his fever down, and he was miserable. And

917
00:47:52,880 --> 00:47:56,920
Speaker 1: I remember a big concern was febrile seizures, which are

918
00:47:57,400 --> 00:48:01,760
Speaker 1: very scary to watch, but currently, based on these websites

919
00:48:01,800 --> 00:48:05,600
Speaker 1: from children's hospitals that I was reading, one quite often

920
00:48:05,680 --> 00:48:09,439
Speaker 1: giving kiddo's medication to bring the fevers down won't necessarily

921
00:48:09,600 --> 00:48:12,479
Speaker 1: reduce the risk of getting that kind of seizure. And two,

922
00:48:12,600 --> 00:48:15,960
Speaker 1: those seizures don't seem to in most cases be associated

923
00:48:16,000 --> 00:48:19,560
Speaker 1: with long term neurological outcomes.

924
00:48:19,120 --> 00:48:20,480
Speaker 2: So you're just supposed to let them happen.

925
00:48:20,960 --> 00:48:23,760
Speaker 1: Again, you should always call your doctor if your kiddo

926
00:48:23,800 --> 00:48:26,600
Speaker 1: has a high fever and go with their advice. But yes,

927
00:48:27,840 --> 00:48:30,000
Speaker 1: and they're more likely to happening kids that are six

928
00:48:30,040 --> 00:48:34,680
Speaker 1: and younger, So, like you know, call your doctor, call

929
00:48:34,760 --> 00:48:35,400
Speaker 1: your doctor.

930
00:48:35,719 --> 00:48:37,520
Speaker 2: Well, it sounds like you're saying that the fever is

931
00:48:37,560 --> 00:48:40,360
Speaker 2: not just a byproduct of your immune system at work,

932
00:48:40,640 --> 00:48:44,160
Speaker 2: but actually part of its tactics, and that by reducing

933
00:48:44,160 --> 00:48:48,000
Speaker 2: your fever, you may be suppressing or inhibiting your immune response.

934
00:48:48,440 --> 00:48:51,360
Speaker 2: I've always thought that reducing your fever helps you sleep

935
00:48:51,400 --> 00:48:55,000
Speaker 2: better and rest, and that would actually be helpful in recovery.

936
00:48:55,640 --> 00:48:58,279
Speaker 2: What is your non medical advice opinion about that?

937
00:48:58,520 --> 00:49:01,479
Speaker 1: Yeah, so w in the Wiener Smith household, I ask

938
00:49:01,920 --> 00:49:05,080
Speaker 1: my kiddos like, hey, if you really feel like you

939
00:49:05,120 --> 00:49:07,480
Speaker 1: can't sleep and you're going to be absolutely miserable all night,

940
00:49:08,120 --> 00:49:10,319
Speaker 1: I will give you medication, but I think you will

941
00:49:10,320 --> 00:49:13,680
Speaker 1: feel better sooner if you can let the fever run

942
00:49:13,719 --> 00:49:16,080
Speaker 1: its course and just try to sleep best you can.

943
00:49:16,560 --> 00:49:19,920
Speaker 1: But for example, my autistic kiddo clearly kind of suffers

944
00:49:19,920 --> 00:49:22,279
Speaker 1: at night when he's got a high fever and is

945
00:49:22,680 --> 00:49:24,600
Speaker 1: not really sure what's going on in a lot of cases.

946
00:49:24,640 --> 00:49:27,360
Speaker 1: And I will give him medication to reduce his fever

947
00:49:27,840 --> 00:49:30,960
Speaker 1: if I think he will if he'll feel better. And

948
00:49:31,320 --> 00:49:32,760
Speaker 1: you know, if I ever thought that he was feeling

949
00:49:32,800 --> 00:49:35,000
Speaker 1: particularly bad, I'd take him to the doctor. But I

950
00:49:35,040 --> 00:49:38,160
Speaker 1: don't take fever reducing meds when I can avoid it, Okay,

951
00:49:38,200 --> 00:49:41,520
Speaker 1: And so Gordon also wanted to know if there are

952
00:49:41,560 --> 00:49:45,920
Speaker 1: any other symptoms of sickness that we should be not

953
00:49:46,280 --> 00:49:48,879
Speaker 1: treating because maybe they're helping in some way.

954
00:49:49,280 --> 00:49:51,799
Speaker 2: Should we be like cracking open our wounds to let

955
00:49:51,840 --> 00:49:53,359
Speaker 2: the blood flow or anything else.

956
00:49:53,680 --> 00:49:57,279
Speaker 1: No, that seems ridiculous. In a lot of cases, it's

957
00:49:57,320 --> 00:50:00,360
Speaker 1: really hard to test this kind of stuff, and so

958
00:50:01,320 --> 00:50:03,000
Speaker 1: I don't know that we have clear answers to too

959
00:50:03,040 --> 00:50:05,120
Speaker 1: many other things. I think fever we've got a pretty

960
00:50:05,120 --> 00:50:06,839
Speaker 1: good handle on the fact that a lot of time.

961
00:50:06,920 --> 00:50:12,719
Speaker 1: Oh oh, real quick, fun medical history fact. So syphilis.

962
00:50:13,160 --> 00:50:16,400
Speaker 1: Not going to go into too many details about where

963
00:50:16,520 --> 00:50:19,759
Speaker 1: you get that disease from, suffice it to say, this

964
00:50:19,920 --> 00:50:24,279
Speaker 1: is a bacterial disease that is very unpleasant, and in

965
00:50:24,320 --> 00:50:28,239
Speaker 1: the era before antibiotics, it could cause neurological issues when

966
00:50:28,280 --> 00:50:29,279
Speaker 1: you couldn't get rid of it.

967
00:50:29,719 --> 00:50:31,680
Speaker 2: You can probably avoid syphilis if you follow the no

968
00:50:31,760 --> 00:50:32,480
Speaker 2: harm theorem.

969
00:50:32,920 --> 00:50:36,840
Speaker 1: That's right, that's right, that's right. This used to be

970
00:50:36,920 --> 00:50:42,759
Speaker 1: treated by giving people malaria, which gives people very high fevers,

971
00:50:43,120 --> 00:50:46,040
Speaker 1: because in some percent of the cases the very high

972
00:50:46,080 --> 00:50:50,439
Speaker 1: fever would kill the bacteria that causes syphilis. And then

973
00:50:50,560 --> 00:50:54,920
Speaker 1: we could treat people with the medication for malaria, and

974
00:50:54,960 --> 00:50:57,560
Speaker 1: then you wouldn't have malaria or have syphilis anymore. And

975
00:50:57,600 --> 00:50:59,680
Speaker 1: someone got the Nobel Prize for that, and then the

976
00:50:59,680 --> 00:51:03,560
Speaker 1: next your penicillin was discovered. And penicillin is way better

977
00:51:03,600 --> 00:51:07,360
Speaker 1: than malaria, so that became the standard treatment anyway. So

978
00:51:07,520 --> 00:51:10,640
Speaker 1: we have used fever as a way to treat disease

979
00:51:10,760 --> 00:51:12,760
Speaker 1: in the past because it is helpful.

980
00:51:13,239 --> 00:51:15,839
Speaker 2: Another medical history note, Katrina was telling me that the

981
00:51:15,880 --> 00:51:19,880
Speaker 2: first trial of penicillin only worked in three out of

982
00:51:19,920 --> 00:51:22,640
Speaker 2: five cases, likely two out of the five patients died.

983
00:51:23,239 --> 00:51:26,279
Speaker 2: And so you know, preliminary studies, like, be careful with

984
00:51:26,360 --> 00:51:29,839
Speaker 2: your conclusions. It's a good thing. We weren't like, oh, penicillin, Nah,

985
00:51:30,080 --> 00:51:31,759
Speaker 2: not really that effective. Let's move on.

986
00:51:32,080 --> 00:51:35,200
Speaker 1: Holy cow, that's wow. Yeah, you gotta be careful with

987
00:51:35,239 --> 00:51:39,640
Speaker 1: small sample sizes. And it's amazing we are in the

988
00:51:39,640 --> 00:51:41,960
Speaker 1: position we're in, nounced. So yes, there are some other

989
00:51:42,040 --> 00:51:46,359
Speaker 1: hypotheses for other sickness behaviors. For example, why do you

990
00:51:46,400 --> 00:51:49,680
Speaker 1: have reduced appetite when you're sick. There's a hypothesis that

991
00:51:49,719 --> 00:51:53,160
Speaker 1: actually the pathogens that are infecting you need nutrients and

992
00:51:53,280 --> 00:51:56,520
Speaker 1: energy as well, and the food that you've just eaten

993
00:51:56,680 --> 00:52:00,000
Speaker 1: is a more easily accessible source of nutrients and energy

994
00:52:00,160 --> 00:52:02,319
Speaker 1: than the food that you've already stored, for example, in

995
00:52:02,400 --> 00:52:05,040
Speaker 1: like fat in your body, and so by eating less,

996
00:52:05,080 --> 00:52:09,560
Speaker 1: you're sort of starving the pathogens more than you're starving yourself.

997
00:52:10,080 --> 00:52:12,360
Speaker 1: I'm not necessarily sure that I buy that, And I

998
00:52:12,400 --> 00:52:15,920
Speaker 1: really love an excuse to have wanton soup when I'm sick.

999
00:52:16,560 --> 00:52:19,680
Speaker 1: But that is a hypothesis that people are floating.

1000
00:52:19,560 --> 00:52:22,160
Speaker 2: That flies in the face of like generations of chicken

1001
00:52:22,200 --> 00:52:24,480
Speaker 2: soup based knowledge. Also it does it?

1002
00:52:24,560 --> 00:52:24,840
Speaker 3: Does?

1003
00:52:25,080 --> 00:52:25,239
Speaker 6: You know?

1004
00:52:25,280 --> 00:52:26,759
Speaker 1: It's an interesting way to think about things.

1005
00:52:27,000 --> 00:52:29,800
Speaker 2: That is Kelly's no soup theorem for treating fevers.

1006
00:52:30,280 --> 00:52:34,359
Speaker 1: Yeah, yeah, I don't know. In my family we buy

1007
00:52:34,360 --> 00:52:38,200
Speaker 1: everybody ice cream. We don't go that route. And then

1008
00:52:38,200 --> 00:52:40,759
Speaker 1: the last one, there's this idea that you know, in

1009
00:52:40,800 --> 00:52:44,120
Speaker 1: a recent episode, we talked about kin selection and the

1010
00:52:44,160 --> 00:52:47,000
Speaker 1: idea that some behaviors are meant to like increase the

1011
00:52:47,040 --> 00:52:50,319
Speaker 1: fitness of your family members. And so there's a hypothesis

1012
00:52:50,320 --> 00:52:55,040
Speaker 1: that sickness behavior, where essentially you withdraw and you isolate yourself,

1013
00:52:55,120 --> 00:52:58,120
Speaker 1: is meant to protect your family from getting sick. And

1014
00:52:58,200 --> 00:53:01,560
Speaker 1: I really feel like I don't necessarily by that, because

1015
00:53:01,640 --> 00:53:04,400
Speaker 1: I feel like when you're sick, your family is the

1016
00:53:04,400 --> 00:53:06,120
Speaker 1: one who like comes in to take care of you,

1017
00:53:06,200 --> 00:53:08,800
Speaker 1: and like you're way less likely to get your community

1018
00:53:08,880 --> 00:53:12,160
Speaker 1: sick and way more likely to get your family sick. Yeah,

1019
00:53:12,200 --> 00:53:14,319
Speaker 1: and so yeah, I don't know that kin selection really

1020
00:53:14,320 --> 00:53:15,359
Speaker 1: helps explain that one.

1021
00:53:15,440 --> 00:53:17,680
Speaker 2: So well, well, when I'm sick, I tend to be

1022
00:53:17,760 --> 00:53:20,319
Speaker 2: miserable and moan a lot, and that makes everybody else

1023
00:53:20,360 --> 00:53:23,000
Speaker 2: around me miserable too, And I'm wondering is that helping

1024
00:53:23,040 --> 00:53:26,279
Speaker 2: me get better? You know? Is complaining actually part of

1025
00:53:26,320 --> 00:53:28,160
Speaker 2: the healing process or is that just part.

1026
00:53:27,960 --> 00:53:28,400
Speaker 5: Of being me?

1027
00:53:29,120 --> 00:53:31,439
Speaker 1: I think from a kin selection standpoint, you should keep

1028
00:53:31,440 --> 00:53:33,560
Speaker 1: complaining so that your family stays away from you and

1029
00:53:33,600 --> 00:53:37,040
Speaker 1: you don't get them sick. I think that's adaptive. Keep

1030
00:53:37,040 --> 00:53:37,440
Speaker 1: doing it.

1031
00:53:37,840 --> 00:53:43,200
Speaker 2: There you go. Yeah, moaning and groaning has reasons people,

1032
00:53:44,400 --> 00:53:47,320
Speaker 2: it's good all right, So Kelly is squashing the no

1033
00:53:47,480 --> 00:53:49,479
Speaker 2: moaning and groaning theorem.

1034
00:53:49,520 --> 00:53:52,040
Speaker 1: No, Daniel can complain as much as he wants. Maybe

1035
00:53:52,040 --> 00:53:55,040
Speaker 1: that's why men are such babies when they're sick. It's,

1036
00:53:55,080 --> 00:53:56,360
Speaker 1: you know, to protect the women.

1037
00:53:56,680 --> 00:54:00,960
Speaker 2: No, I don't that's right exactly, it's all trueistic.

1038
00:54:00,400 --> 00:54:05,000
Speaker 1: Actually no, no, yeah, no, I don't like where that's going.

1039
00:54:05,239 --> 00:54:08,120
Speaker 2: All right, Well, before we digress into dangerous topics, let's

1040
00:54:08,120 --> 00:54:10,920
Speaker 2: send this answer to Gordon and here if we have

1041
00:54:11,000 --> 00:54:12,080
Speaker 2: answered his question.

1042
00:54:12,520 --> 00:54:14,759
Speaker 7: Wow, thanks for looking into this and answering my question

1043
00:54:15,040 --> 00:54:17,600
Speaker 7: well confirm my suspicion about the potential benefits of not

1044
00:54:17,640 --> 00:54:20,080
Speaker 7: resisting a fever. I had no idea we shared this,

1045
00:54:20,120 --> 00:54:22,560
Speaker 7: particularly me in response with such a diverse range of animals,

1046
00:54:22,600 --> 00:54:25,840
Speaker 7: even its distantly related as the ectotherms. I find the

1047
00:54:25,880 --> 00:54:28,200
Speaker 7: idea of using one disease to treat another somewhat ironic,

1048
00:54:28,280 --> 00:54:30,600
Speaker 7: given the one being used just happens to be one

1049
00:54:30,600 --> 00:54:33,440
Speaker 7: of the deadliest in human history. But then I'm reminded

1050
00:54:33,440 --> 00:54:36,040
Speaker 7: we actually have a long history of using different diseases, parasites,

1051
00:54:36,080 --> 00:54:38,759
Speaker 7: and infections against each other for medical purposes, which is

1052
00:54:38,800 --> 00:54:40,479
Speaker 7: probably a whole topic on its own.

1053
00:54:41,000 --> 00:54:41,360
Speaker 2: Anyway.

1054
00:54:41,400 --> 00:54:43,839
Speaker 7: Thanks for answering my questions, all right, Thank.

1055
00:54:43,760 --> 00:54:45,960
Speaker 2: You very much everybody who sends in your question who

1056
00:54:46,000 --> 00:54:49,080
Speaker 2: shares their curiosity with us and with a wider community

1057
00:54:49,080 --> 00:54:51,920
Speaker 2: of listeners. If you would like to chat with everybody

1058
00:54:51,920 --> 00:54:54,239
Speaker 2: about questions on your mind, you could always send your

1059
00:54:54,320 --> 00:54:57,160
Speaker 2: questions to us two questions at Daniel and Kelly dot org.

1060
00:54:57,280 --> 00:54:59,440
Speaker 2: Or if you'd like to chat with the community of listeners,

1061
00:54:59,520 --> 00:55:01,440
Speaker 2: join the day Score. You can find the link on

1062
00:55:01,560 --> 00:55:06,040
Speaker 2: our website www dot Danielankelly dot org. Come and chat

1063
00:55:06,040 --> 00:55:06,439
Speaker 2: with us.

1064
00:55:06,760 --> 00:55:15,840
Speaker 1: Thanks for listening. Have a good one. Daniel and Kelly's

1065
00:55:15,880 --> 00:55:19,520
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00:55:19,560 --> 00:55:20,239
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1067
00:55:20,360 --> 00:55:23,279
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00:55:23,520 --> 00:55:26,120
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1069
00:55:26,239 --> 00:55:29,200
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1070
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1072
00:55:32,920 --> 00:55:36,440
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1073
00:55:36,480 --> 00:55:39,680
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1074
00:55:38,719 --> 00:55:40,840
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1075
00:55:40,920 --> 00:55:44,719
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1076
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1077
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1078
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