Speaker 1: Brought to you by Toyota. Let's go places. Welcome to
Speaker 1: Forward Thinking. Hey there, and welcome to Forward Thinking, the
Speaker 1: podcast that looks at the future and says, inside the
Speaker 1: cell is a tiny double helix another fancy word or
Speaker 1: d n A. I'm Jonathan Strickland and I'm Joe McCormick.
Speaker 1: And today we're gonna be recording the first part of
Speaker 1: a two part episode on one of the most interesting
Speaker 1: molecules in the entire universe. Dare I say the single
Speaker 1: most interesting molecule. I mean it depends on if you
Speaker 1: like yours at your nucleic acids being ribos oriented or
Speaker 1: de ox. Get that ribos out of my head. This
Speaker 1: is d n A. It's d n A time. So
Speaker 1: this is gonna be part one. Uh, and today we're
Speaker 1: going to mostly be focusing on the history and the
Speaker 1: current research around using DNA. But please stick with us
Speaker 1: also for next time when we're going to focus on
Speaker 1: some topics aroun using DNA as a technological tool. Yeah,
Speaker 1: and uh, as we record this, it is April twenty five,
Speaker 1: which is National DNA Day. Complete coincidence, but a lovely coincidence. Yes,
Speaker 1: I had no idea. Yeah, we didn't. I just happened
Speaker 1: to find it while I was doing a search on
Speaker 1: news about DNA. And the reason it is National DNA
Speaker 1: Day is that on this day in two thousand three,
Speaker 1: the Human Genome Project completed its quest to to map
Speaker 1: out the human genome. So there you go, Happy National
Speaker 1: DNA Day. So where's the treasure buried? Sadly, we don't
Speaker 1: have all the information necessary to find the treasure? Here
Speaker 1: here's the last part is stored in an our two
Speaker 1: unit that we came. Yeah, it was not going to
Speaker 1: go down the force unleashed path of logic. There in
Speaker 1: lies madness. But I do want to say that I
Speaker 1: read us an interesting thing from one of the researchers
Speaker 1: who worked on the genome project, and because they're often asked, well,
Speaker 1: if you mapped out the genome, why haven't we cured
Speaker 1: cancer yet? Right, And they said, well, think of it
Speaker 1: this way. Imagine that the human genome is really a
Speaker 1: collection of ancient books written in a language no one
Speaker 1: speaks or writes in anymore. You have just spent more,
Speaker 1: you know, a decade or more, collecting all of the books,
Speaker 1: and now you are absolutely certain that you have all
Speaker 1: the books that make up the entire collection of this
Speaker 1: one library, but just still can't read them yet, all
Speaker 1: of them, or at least not all of them. And
Speaker 1: that's what is going to be taking up a lot
Speaker 1: of time for the next decade or so while we
Speaker 1: while we learn what these books say and what they
Speaker 1: mean and how to use them. Yeah. Right now we've
Speaker 1: got the equivalent of like run spot run yeah, or
Speaker 1: go spot go. I'm behind on my board book titles.
Speaker 1: Let's see Dick and Jane is what you're talking about?
Speaker 1: That that kind of thing. But uh, but yeah, So
Speaker 1: so today, in this first episode, we wanted to just
Speaker 1: talk about what DNA is and what it is being
Speaker 1: used for currently. Look go into a little bit of
Speaker 1: the history of of how it was potentially created here
Speaker 1: on the planet Earth, and also how we discovered it,
Speaker 1: because you know, it's a relatively resdiscovery in human history, right,
Speaker 1: So let's start with the basics at base. DNA is,
Speaker 1: of course chemistry, but as we all know, it's the
Speaker 1: basis for all of the stuff we know of in
Speaker 1: the universe that is definitely in the alive category, though
Speaker 1: maybe not some things that are just maybe sort of alive,
Speaker 1: like prions and we're not going to do all the
Speaker 1: standard stuff you learned in school about what DNA does,
Speaker 1: but just for a brief refresher, the really simple version,
Speaker 1: what does DNA do well. You can think about your
Speaker 1: body as a type of machine, and that machine is
Speaker 1: made up of parts, and most of these parts are proteins.
Speaker 1: Proteins are like tiny, very simple robots that work together
Speaker 1: to make more complex robots that are your organs, which
Speaker 1: of course has work together to make the real robot,
Speaker 1: which is you. But they're all these little robots in
Speaker 1: your body and their proteins. So what makes these proteins.
Speaker 1: The answer is d n A. DNA or de oxy
Speaker 1: ribonucleic acid, is a long chain molecule. It's one really
Speaker 1: huge long molecule that contains an ordered sequence of what
Speaker 1: are called nucleotides. These are the building box of the
Speaker 1: d n A and the sequence of the nucleotides, what
Speaker 1: order they come in determines what proteins get made and
Speaker 1: how they get used. So DNA, you can think of
Speaker 1: it as like both the code for what your body
Speaker 1: should be like and also the machine that builds the
Speaker 1: machines that builds the machines that build your body, one
Speaker 1: protein at a time. Now, if you find all that confusing,
Speaker 1: you can just refer to the helpful educational film Mr
Speaker 1: DNA at the beginning of Jurassic Park, which is so
Speaker 1: good is actually, where did you come from? I watched
Speaker 1: it again before we before we recorded the show. So
Speaker 1: let's talk about, like, well, where do we think DNA
Speaker 1: came from? Like where? What? Why? We know that it's
Speaker 1: it's integral to life here on Earth. How did it
Speaker 1: get started? That's a really interesting question, and it's easily
Speaker 1: a whole episode in itself, So we can't explore that
Speaker 1: entirely here if we want to get to all the
Speaker 1: other stuff we were going to talk about today. But
Speaker 1: the short answer is this is still a really big,
Speaker 1: unsettled question in the origins of life in biochemistry. We
Speaker 1: have some good ideas, but nobody really knows with confidence
Speaker 1: yet where DNA came from an exactly what role it
Speaker 1: played in the emergence of life on Earth, for example,
Speaker 1: one big question, Like we said earlier, DNA is the
Speaker 1: basis of pretty much all life on Earth today, But
Speaker 1: which came first? D NA or life? Was there non
Speaker 1: DNA based life before there was DNA based life? Yeah,
Speaker 1: it's one of those chicken or the egg kind of
Speaker 1: kind of questions. Exactly it really is and uh, it's
Speaker 1: the There have been plenty of people looking into trying
Speaker 1: to at least hypothesize where DNA came from, whether or
Speaker 1: not it was a product of some early form of life,
Speaker 1: or if in fact it was the thing that allowed
Speaker 1: life to emerge. Yeah, and one issue here is that
Speaker 1: DNA is a it's a very complex molecule. It doesn't
Speaker 1: and so for this reason, people generally don't think it
Speaker 1: looks like something that would randomly self as symbol without
Speaker 1: some sort of precursor. Uh. And so a lot of
Speaker 1: the question that allow the investigations on where did DNA
Speaker 1: come from? Or looking at like well, what could a
Speaker 1: chemical precursor be? What could there have been that facilitated
Speaker 1: the creation of this really complex molecule. And one very
Speaker 1: popular theory, though we don't know it's the answer yet,
Speaker 1: it's a strong hypothesis, is the so called RNA world
Speaker 1: So ribonucleic acid. Yeah, this is a somewhat simpler molecule
Speaker 1: than dnah. Yeah, Yeah, let's clarify the difference there between
Speaker 1: the two. All right, So they're both nuke aic acids. Uh,
Speaker 1: First of all, the sugar element of the nucleic acids
Speaker 1: that they're composed of a sugar element as well some
Speaker 1: other pieces, But the sugar element is different from both.
Speaker 1: You have de oxy ribos for DNA and just ribos
Speaker 1: for RNA. That's that's a major difference right there. Who
Speaker 1: who Who gets out of bed for ribos? Really, you
Speaker 1: got to hold out for that d oxy ribos if
Speaker 1: you if you're lacking DNA, you're not kicking out of bed.
Speaker 1: DNA is double stranded. You always think of that that classic, uh,
Speaker 1: double helix twisted ladder we'll talk about in a minute.
Speaker 1: RNA is a single strand molecule. DNA stores and transfers
Speaker 1: genetic information and humans. RNA codes for amino acids and
Speaker 1: acts kind of like a messenger between DNA and ribosomes
Speaker 1: to make proteins. So those are the differences. So let's
Speaker 1: talk about some of the research. In two thousand nine,
Speaker 1: a group of scientists successfully synthesized two of the four
Speaker 1: nucleotides that make up RNA using chemicals that we believe
Speaker 1: we're present on primordial Earth. So this does not necessarily
Speaker 1: mean that the hypothesis is true. It just means it
Speaker 1: makes it sort of plausible, at least for urna right,
Speaker 1: that RNA could spontaneously form based upon some conditions on Earth.
Speaker 1: And again, it's only the proof of two of those
Speaker 1: four nucleotides. They're still working on the other two to
Speaker 1: see if there's a way that the chemicals that we
Speaker 1: think we're around in primordial Earth could have developed into
Speaker 1: these building blocks for RNA. Um Now, one of those
Speaker 1: scientists have since has since gone on to see if
Speaker 1: he can do the same thing with DNA nucleotides using
Speaker 1: a similar approach to that RNA experiment. Uh, but sugars
Speaker 1: in DNA nucleotides are harder to work with in RNA
Speaker 1: counterparts before you actually assemble into DNA. Once it's assembled
Speaker 1: in DNA, it's really stable. Yeah, but before then it's
Speaker 1: just tough to work with. So ultimately, we still don't
Speaker 1: know if RNA and so DNA preceded life, but at
Speaker 1: least the work that we've seen so far suggests that
Speaker 1: it's still plausible. It's it's not necessarily um a dead
Speaker 1: end yet until we get to a point that we
Speaker 1: have to say, well, we've tried everything. We can't get
Speaker 1: any of these chemicals to work out the way we
Speaker 1: thought it would back on the primordial Earth conditions. Maybe
Speaker 1: there's an alternative answer to this question. Yeah, it's a
Speaker 1: fascinating question, absolutely crazy that we don't know the answer
Speaker 1: to this, and so it's so exciting to read about,
Speaker 1: you know, what we're learning. Yeah, so it's so big
Speaker 1: and basic. Other research that I've read indicated that another factor,
Speaker 1: meteor impacts in primordial Earth, might have been the key
Speaker 1: to putting all of this together. Um and Okay. One
Speaker 1: of the theories about how DNA and life in general
Speaker 1: arose on Earth is that amino acids and nucleotides hitched
Speaker 1: a ride here on meteors and other bodies that you know,
Speaker 1: we're from elsewhere, and that's how they got here. Now,
Speaker 1: of course that doesn't answer the question of how they
Speaker 1: were assembled, but that's how they arrived on this planet. Sure,
Speaker 1: which is you know, yeah, it's it's a it's a
Speaker 1: set of questions that also go together. Clearly, the lizard
Speaker 1: people put it together, right, and they put it on
Speaker 1: rocks and pushed them to Earth. Well, absolutely, is that
Speaker 1: what you call those naked dudes in prometheus lizard people
Speaker 1: I call them frequently. Go ahead, Lauren, excellent. So there
Speaker 1: has been though skepticism in the research community about whether
Speaker 1: that the breadth of amino acids and nucleotides that we
Speaker 1: see here on Earth could have possibly arrived intact, or
Speaker 1: even could have formed from things that might have arrived intact.
Speaker 1: But so there was the study that was published back
Speaker 1: in August by team out of Japan, and they simulated
Speaker 1: a meteorite hitting an ancient ocean, and they found that
Speaker 1: the energy from the impact, together with the raw physical
Speaker 1: materials that the inorganic compounds that were likely to have
Speaker 1: been present, could indeed have formed armed nucleo nucleotides and
Speaker 1: amino acids. They they found when they when they studied
Speaker 1: their post impact stuff, they found nine amino acids that
Speaker 1: are all involved with the formation of proteins and also
Speaker 1: to nucleotides. So that's that's pretty fascinating. That's really an
Speaker 1: interesting idea. And obviously, if we were to study this
Speaker 1: further and and conclude that in fact these molecules were
Speaker 1: extraterrestrial in nature, as Joe was pointing out, that then
Speaker 1: leads to a whole new series of questions. Which or
Speaker 1: maybe even more interesting. Yeah, yeah, the and it may
Speaker 1: be that perhaps these are questions that are are ultimately
Speaker 1: unknowable to us. We don't know, maybe that that we
Speaker 1: will have a certain percentage of certainty for one versus another,
Speaker 1: but uh, I'm not entirely certain short of time travel,
Speaker 1: how we would ever get to the very bottom of this, like,
Speaker 1: what would be the the conclusive proof that would uh
Speaker 1: make one hypothesis stand well over the other. It seems
Speaker 1: like probably the best we could hope to do is
Speaker 1: if we could offer a lot of hypotheses and note
Speaker 1: that eventually one of them works under lab conditions and
Speaker 1: the others don't, which gives you some degree of confidence
Speaker 1: that that's probably the right answer. But we'll never really know,
Speaker 1: right right, it's not really approvable hypothesis. Um but but hey, okay, so,
Speaker 1: speaking of time travel, we have here in the studio
Speaker 1: with us today the way back machine from tech stuff, Yeah,
Speaker 1: tech stuff and stuff you should know. I mean, it's
Speaker 1: been a long time since I've seen this baby, and
Speaker 1: I gotta tell you it's a little worse for wear.
Speaker 1: I'm pretty sure the stuff you should know, guys have
Speaker 1: been going back to the sixties for some fun. But yeah,
Speaker 1: let's us and chalk. Let's put it to use and
Speaker 1: really find out. Like, let's let's talk about the actual
Speaker 1: discovery of d n A, not not when it was
Speaker 1: potentially first formed on Earth, but when we humans first
Speaker 1: became aware of it. Okay, well, you may have heard
Speaker 1: this story before. Of course. The answer is that Watson
Speaker 1: and Crick discovered DNA in the nineteen fifties. Except that's
Speaker 1: not true. But the book told me, no, this is
Speaker 1: the thing for some reason, even my I've read about
Speaker 1: this before, and even my brain goes to this place. Yeah,
Speaker 1: Watson and Crick discovered DNA. That's not true. Uh so
Speaker 1: who really did discover d NA? What is it that
Speaker 1: Watson and Crick supposedly discovered or or contributed to our
Speaker 1: understanding of DNA. One interesting fact to point out, people
Speaker 1: knew about heredity before they knew about DNA, and this
Speaker 1: is a thing that can easily be lost because we
Speaker 1: now equate to DNA in standard conversation with the idea
Speaker 1: of heritable and information. So you get stuff from your parents,
Speaker 1: people just say, oh, it's in your d n A.
Speaker 1: But that that is a relatively recent thing to enter
Speaker 1: the common parlance, and so people knew about inheriting traits
Speaker 1: from parents long before they knew what the molecule was
Speaker 1: in the body that conveyed that information. Right, right, So
Speaker 1: in order to get to the bottom of this question,
Speaker 1: we're going to go back in our way back machine
Speaker 1: to eighteen sixty nine. Oh, that's why the numbers are.
Speaker 1: I was wondering. I just thought that was just randomly
Speaker 1: put there when I was saying sixties, I actually did
Speaker 1: me the eighteen sixties. Well, what were there good party
Speaker 1: times there too? I just assumed if Josh and Chuck
Speaker 1: were doing it. But now I know that nine was
Speaker 1: set for us. You ever seen Gone with the Wind,
Speaker 1: there's lots of parties. Yeah right, let's just don't look
Speaker 1: like a lot of fun. Let's just get in the
Speaker 1: way back machine and go check out where we're going. Okay,
Speaker 1: we're here, and there's so much pus. So in eighteen
Speaker 1: sixty nine, there's this Swiss biochemist at the University of
Speaker 1: tubing In and his name is Johann Friedrich Mescher, and
Speaker 1: he was studying puss. That explains this then, no joke. Yeah,
Speaker 1: so there's plus everywhere. Mitscher had a. He had an arrangement,
Speaker 1: you might say, with a nearby surgical clinic that would
Speaker 1: send him filthy used bandages that were dripping with pus.
Speaker 1: And you know, when you think about filthy used bandages
Speaker 1: dripping with pus, most people you wouldn't want to handle them,
Speaker 1: you know, do things with them, spend your Saturday on them.
Speaker 1: Not not way up on my list of things to do.
Speaker 1: But in fact, these pus soaked bandages turned out to
Speaker 1: be a scientific gold mine because of the following reason.
Speaker 1: So plus contains mostly dead lucacites, which are white blood cells.
Speaker 1: He was studying these white blood cells to understand the
Speaker 1: proteins in them. But Mescher also discovered in the course
Speaker 1: of his research that in the nucleus of each of
Speaker 1: the white blood cells there was a common substance that
Speaker 1: had nitrogen and phosphorus atoms in it and which was
Speaker 1: chemically distinct from the protein. So it's this stuff there
Speaker 1: in the cell nucleus. It's not a protein. It's got
Speaker 1: nitrogen and phosphorus. It is it. And he called this
Speaker 1: stuff nucleon, which later became known as nucleic acid. And
Speaker 1: once it was totally isolated from the surrounding proteins and
Speaker 1: all the other stuff. The pure molecule got the name
Speaker 1: we know today de oxy ribonucleic acid or d n A. Well,
Speaker 1: this is fascinating, Joe, but I would like us all
Speaker 1: to take a pledge that none of us will utter
Speaker 1: the word PUS again in the rest of this episode.
Speaker 1: I will with with one small exception, and that is,
Speaker 1: can we get out of this PUS party? I would
Speaker 1: I would like, do you have any parties to take
Speaker 1: us to that aren't made of pus? Well, let's see
Speaker 1: where we could go on the quickly summarized scientific research
Speaker 1: bandwagon party. Well, luckily there's a montage button inside the
Speaker 1: way back machines and just hit that. Yeah, now we
Speaker 1: gotta go on the montage because there are actually a
Speaker 1: bunch of scientists over the ensuing decades that contributed a
Speaker 1: lot more to the study of heredity and d n A,
Speaker 1: And we don't have time to go into all of
Speaker 1: their research. But but so after me share at this point,
Speaker 1: you know that there are genes that convey traits from
Speaker 1: parents to offspring, and we know about DNA, but we
Speaker 1: hadn't put them together. We didn't know that one was
Speaker 1: the DNA was the agent of heredity. And so in
Speaker 1: nineteen forty four group of scientists Avery, McLeod and McCarty
Speaker 1: showed that DNA conveys hereditary traits, that DNA is the
Speaker 1: agent of mendalian genetics. And finally, in nineteen fifty three,
Speaker 1: you finally got to Krick and Watson, plus a couple others, Actually,
Speaker 1: Francis Crick, James Watson, Maurice Wilkins, and Rosalind Franklin demonstrated
Speaker 1: the structure of DNA. So they put together the model
Speaker 1: of the double helix molecule of DNA, the one we've
Speaker 1: all seen now. It looks like a ladder that you
Speaker 1: twisted up like a spring or like a like a
Speaker 1: like a spiral staircase. Yeah, yeah, spiral ladder, I guess, yeah. Uh.
Speaker 1: And so it's got two spiraling parallel pull ales that
Speaker 1: are connected by rungs of nucleo basis. And the important
Speaker 1: thing about discovering the double helix shape of the molecule
Speaker 1: was that this showed how the DNA molecule was capable
Speaker 1: of conveying genetic information. Well, let's let's go ahead and
Speaker 1: pop on back over into a modern day and back
Speaker 1: into our studio and and and just concentrate more about
Speaker 1: uh little other stuff we've learned about this amazing molecule. Okay, yes,
Speaker 1: this is better for reasons that I've promised not to
Speaker 1: mention again. Um okay, Joe, you are so lucky the
Speaker 1: the Acts of Mysticism is not currently in the podcast studio.
Speaker 1: Not the Mystical Acts. You never used the Mystical Acts
Speaker 1: as a weapon. I'm sorely tempted. Okay. So, despite this
Speaker 1: rich history of research into into DNA, there's still so
Speaker 1: much that is going on in the field, all these
Speaker 1: studies being conducted, questions being answered, new questions that we
Speaker 1: never even conceived of being posed. And so so we
Speaker 1: wanted to give y'all a quick sample of some of
Speaker 1: the stuff we've seen recently, just to give you an
Speaker 1: idea of of what kind of things are going on. Yeah. So,
Speaker 1: first of all, we were talking about that double helix shape.
Speaker 1: One of the interesting bits of research that we encountered
Speaker 1: while looking into the topic was that some scientists have
Speaker 1: shown that DNA doesn't just hold that double helix shape. Yeah,
Speaker 1: it actually comes in lots of fun shapes. Yeah. So
Speaker 1: I as I as I said, is it kind of boogies.
Speaker 1: It moves around a lot. And actually, when you think
Speaker 1: about get stars, moons and balloons and clovers, it's not
Speaker 1: the Lucky Charm shapes, although some of them are similar
Speaker 1: to them. All right, So what's the deal here. We've
Speaker 1: been told about this double helix shape forever. Why are
Speaker 1: we suddenly seeing different shapes? Well, part of what I've
Speaker 1: read is that when Watson and Crick were really described
Speaker 1: the structure of DNA, they were looking at a length
Speaker 1: of DNA that was about twelve base pairs long, something
Speaker 1: like that, like one turn of DNA. But DNA has
Speaker 1: to turn many, many, many times. It has to be
Speaker 1: super coiled because DNA is a very long molecule. But
Speaker 1: it has to fit within the nucleus of a cell, right,
Speaker 1: And most nucleus nucleus is nuclei of cells are not
Speaker 1: a few meters long. It really the length of a
Speaker 1: DNA chain, right, So to fit that inside a cell's nucleus,
Speaker 1: you have to coil and coil and coil and coil.
Speaker 1: This this shape. And if you've ever dealt with any
Speaker 1: kind of like cable or anything, any real long length
Speaker 1: of of something that's got lots of kinks, and then
Speaker 1: you can see all sorts of weird shapes. And also
Speaker 1: as you uncoil it, it can spring in ways that
Speaker 1: are terrifying. Uh So the DNA molecule ends up creating these,
Speaker 1: uh these other odd shapes that that the scientists were
Speaker 1: able to observe. Um it was kind of interesting how
Speaker 1: they did it. They used a method called cryo electron
Speaker 1: tomography uh to study the the actual shapes, and they
Speaker 1: observed all sorts of interesting ones, like figure eights or
Speaker 1: coiled so tightly that look like it was a rod,
Speaker 1: not even two separate strands anymore. Also, according to one
Speaker 1: of the scientists, some of them look like rackets or handcuffs.
Speaker 1: So maybe maybe if your molecules are being naughty in
Speaker 1: your cells nucleus, the DNA will just go ahead and
Speaker 1: slap the cuffs on. I don't know how that works
Speaker 1: at any rate. No clovers though, no clovers that I saw.
Speaker 1: I mean, it's entirely possible that it just was not
Speaker 1: included on the list. Probably probably horseshoes, though if you
Speaker 1: crossed a couple of pairs of handcuffs, you'd essentially have
Speaker 1: a clover. Yeah, I would allow for the possibility that
Speaker 1: a clover could in fact be one of the many
Speaker 1: shapes that DNA could take, but depending on the coiling. Uh.
Speaker 1: The important thing here, though, is that understanding the shape
Speaker 1: of the molecules can help doctors developed better medicines and
Speaker 1: scientists helped develop better medicines because the the drugs we take,
Speaker 1: typically what does It releases some molecules into our system,
Speaker 1: and those molecules are looking for other molecules of a
Speaker 1: specific shape. So knowing more about the shape of DNA
Speaker 1: can make more effective medicines that are specifically looking for
Speaker 1: those shapes. So it does have a practical application. It's
Speaker 1: not just the idea of we just want to learn more, although,
Speaker 1: as we say on the show all the time, that
Speaker 1: then itself is a worthy endeavor most of the time. Okay,
Speaker 1: how about one other really interesting fact about DNA. We
Speaker 1: mentioned earlier, how there was the discovery over time that
Speaker 1: DNA is the gene, that DNA is the molecule in
Speaker 1: the body that conveys genetic information from parent to offspring.
Speaker 1: But one of the weird facts that we're discovering we
Speaker 1: actually started discovering in the twentieth century, but that we're
Speaker 1: learning more about all the time. Is something called horizontal
Speaker 1: gene transfer, which is where you can get a gene
Speaker 1: in your genome that doesn't come from your parents. Doesn't
Speaker 1: happen very often with humans, happens all the time with
Speaker 1: single celled organisms like bacteria, where where they can trade genes.
Speaker 1: It's almost like a way for bacteria to sort of
Speaker 1: have sex. They don't really, but they can exchange genetic
Speaker 1: information back and forth between their genomes and UH. And
Speaker 1: it turns out that there appears to be DNA within
Speaker 1: the genomes of larger organisms that looks like it probably
Speaker 1: came from organisms other than this organism's direct ancestors. Yeah. Yeah,
Speaker 1: and you might wonder how could something like that happen uh,
Speaker 1: And in fact, it can happen through something that's called
Speaker 1: the endogenous retrovirus or e r V s UM. These
Speaker 1: are retroviruses that once infected UH some sort of organism
Speaker 1: in the past, and they're really really really replicating themselves,
Speaker 1: at least for a few generations until mutations make that
Speaker 1: a non factor. So the way this works as a
Speaker 1: retrovirus can replicate self by infiltrating a cell a host
Speaker 1: cell and inserts some of its own viral genome into
Speaker 1: the nuclear genome of the host cell. So it's sort of,
Speaker 1: you know, hacking into the mainframe, putting a copy of
Speaker 1: itself into the host cell. Now this you this can
Speaker 1: include doesn't normally include it usually, but it can include
Speaker 1: a germline cells. Those are the cells that produce egg
Speaker 1: and sperm cells. And once in a while, even more
Speaker 1: rarely and infected germline cell will go on to develop
Speaker 1: into a viable organism. And so then you'll have this
Speaker 1: viral genome become part of the genome of the overall organism.
Speaker 1: And that's where you get this this mysterious DNA that
Speaker 1: would not have been part of a typical individual of
Speaker 1: that organism species. It's actually been introduced through this virus. Yeah,
Speaker 1: and these strains of the genome, the viral genome can
Speaker 1: remain in the organism's genome over the course of numerous generations,
Speaker 1: over millions of years in fact. But because organisms undergo mutation,
Speaker 1: typically uh, one mutation or another is going to render
Speaker 1: the the viral genomes ability to replicate the actual virus
Speaker 1: null and void. So you'll you'll eventually get to a
Speaker 1: point where the organisms have the viral genome as part
Speaker 1: of their d N A, but they're not making the
Speaker 1: virus anymore because of other unrelated mutations that that organism
Speaker 1: species has undergone over multiple generations. Uh yeah, And and
Speaker 1: no one's really sure how much of our DNA could
Speaker 1: have possibly been influenced by this kind of process. Some
Speaker 1: estimates have it as high as like eight percent, which
Speaker 1: is crazy. Yeah, now, one that is amazing. But one
Speaker 1: thing to clarify is that you shouldn't misunderstand. You shouldn't
Speaker 1: think it. Oh, if I have eight percent of my
Speaker 1: genome from bacteria or viruses or some of their organisms
Speaker 1: on Earth, it's not like that happened since you were
Speaker 1: born then like over the generations this many horizontal gene
Speaker 1: transfer events have accumulated into the genome that created you
Speaker 1: when you were born, right right, um. And but part
Speaker 1: of the reason that it's difficult to suss out how
Speaker 1: this happens is that it's really hard to get direct
Speaker 1: observational evidence of it. And one what one bit of
Speaker 1: research that that we ran across was this this study
Speaker 1: into a transfer between pine trees and insects that happened
Speaker 1: millions of years ago and basically has made pine trees
Speaker 1: what they are today and just and you know, it's
Speaker 1: the first time that we've it's one of the few
Speaker 1: times rather that we have directly observed being able to
Speaker 1: directly trace that kind of data. So cool stuff. It's
Speaker 1: really interesting. If you all don't mind me plugging on
Speaker 1: the other podcast that I do Steff to blow your mind,
Speaker 1: Robert Lamb and I did an episode on horizontal gene
Speaker 1: transfer back in December, I think, so if you want
Speaker 1: to check that out, there's a whole episode on that awesome. Yeah.
Speaker 1: Uh well. One of the other questions that has been
Speaker 1: kind of roiling around in the scientific community is how
Speaker 1: cells protect their DNA m M with extreme prejudice. It's yes,
Speaker 1: I mean, and that is the answer really because okay, so,
Speaker 1: so the inner cell mechanics involving DNA are are complex
Speaker 1: because DNA is stored in its cells nucleus um. The
Speaker 1: nucleus is surrounded by this complex structure called the nuclear envelope,
Speaker 1: which contains a series of gates that lead in and
Speaker 1: out of it, which is called the nuclear poor complex.
Speaker 1: And you know, molecules have to get in and out
Speaker 1: of the nucleus so that cell could like create proteins
Speaker 1: and do stuff, but the envelope also has to be
Speaker 1: vigilant because if a virus can penetrate it, then it'll
Speaker 1: hijack the cells DNA to do its bidding bad times. Um.
Speaker 1: And there are even some diseases that specifically weaken the
Speaker 1: envelope and make your cell nuclei more suceptible to viral infection.
Speaker 1: But it's difficult to study because because in terms of
Speaker 1: cell proportion, the envelope is huge and and the poor
Speaker 1: complex is constantly shifting. Researchers the research that I read
Speaker 1: referred to it like as like jiggling, like like gelatine,
Speaker 1: like a big old bowl or jelly. Um. So, so
Speaker 1: it's been really hard to to get it to get
Speaker 1: a handle on. And this team out of cal Tech
Speaker 1: has been working on it for like a decade and
Speaker 1: finally uh in in in this year in ten started
Speaker 1: to publish results that explain exactly how molecules get transferred
Speaker 1: uh or transported rather like like lead into and out
Speaker 1: of the pores, and how data is moved from DNA
Speaker 1: to r n A to ribosomes, which, as we said earlier,
Speaker 1: do that actual work of some the sizing proteins within cells.
Speaker 1: So so so learning about all of this is is
Speaker 1: just really cool and could help us suss out how
Speaker 1: to protect ourselves against viral infections. Well, that's obviously a
Speaker 1: good thing because of how dependent we are on our DNA.
Speaker 1: Isn't it kind of annoying that we've got a cow
Speaker 1: to out to this tiny little molecule. Why can't we
Speaker 1: be the boss? Why can't we make DNA do what
Speaker 1: we wanted to do? Well, we're getting there. Uh, it's
Speaker 1: it's it's complicated, but we're getting there. What's really cool
Speaker 1: is that we've actually seen some some scientists work with
Speaker 1: DNA as if it were a programming language, right, Like
Speaker 1: it is essentially a set of instructions. So if you
Speaker 1: were able to write a specific set of instructions, you
Speaker 1: could in theory make some sort of cell do something
Speaker 1: that you wanted to do. Um. So, some synthetic biologists
Speaker 1: have been working with DNA to find ways to manipulate
Speaker 1: it and program it in this way. So some m
Speaker 1: I T developed a software CELLO C E L l O.
Speaker 1: That's essentially because of the way I'm I'm talking right now,
Speaker 1: it sounds like I'm saying jello. Uh. No, It makes
Speaker 1: me wonder why didn't they just go ahead and stick
Speaker 1: an H in there. Yeah, it would have been funny. Cello. Uh.
Speaker 1: That's essentially a programming language for DNA. I'm sure it
Speaker 1: stands for something, and I just didn't see what it
Speaker 1: stood for. Wait a minute, a programming language for DNA.
Speaker 1: Now that's interesting because often oftentimes people use the analogy
Speaker 1: of a programming language to describe DNA. Right, So this approach,
Speaker 1: what does It allows people who are not advanced synthetic
Speaker 1: biologists to come up with ways of programming a strand
Speaker 1: of DNA to execute a specific type of instruction under
Speaker 1: a specific circumstances. So, in classic computing terms, you can
Speaker 1: think of it as an if then if sell encounters X,
Speaker 1: then do action Y like that sort of thing. You
Speaker 1: can actually prob ramm it to do that sort of stuff.
Speaker 1: That's fascinating. It's pretty cool. So one of the examples
Speaker 1: that I read about in Nature that was that where
Speaker 1: this article was published, said, imagine that you you create
Speaker 1: a strand of DNA that tells the cell to produce
Speaker 1: a certain drug whenever the cell detects a particular set
Speaker 1: of metabolic conditions. So, in other words, if that those
Speaker 1: metabolic conditions are present, the cell goes into production mode
Speaker 1: and starts producing this drug, you could easily see how
Speaker 1: something like that could be incredible for different medicinal purposes. Yeah, hypothetically.
Speaker 1: I mean, I'm not sure if this is something that
Speaker 1: would be possibly on the table. But if if your
Speaker 1: if your body starts producing histamines in response to some
Speaker 1: kind of allergen that it's just freaking out about, then
Speaker 1: your cells could detect those histamines and create antihistamines to
Speaker 1: calm everything down. I would like that because I miss shrimp. Yeah,
Speaker 1: that's all right, that's all right. I've got other things
Speaker 1: I can eat. I don't really mind. Well, maybe maybe
Speaker 1: that's coming in the future, I should hope so, because
Speaker 1: a friend of mine was shared a picture of shrimp
Speaker 1: and grits on Facebook, and now that's all I can
Speaker 1: think about all that terrible human You listeners out there
Speaker 1: should know that Jonathan and I were sitting in the
Speaker 1: studio before recording and he was just mourning the fact
Speaker 1: that he couldn't meet this shrimp. It was pretty rough,
Speaker 1: but but it's all right. There are bigger problems in
Speaker 1: the world than my allergy to shellfish. One of those
Speaker 1: problems actually is how do we produce synthetic DNA in
Speaker 1: a way that is uh cost effective and and is
Speaker 1: relatively simple, because, as it turns out, making DNA in
Speaker 1: the lab is expensive, it's complicated, takes a lot of energy.
Speaker 1: Oh yeah, I didn't even think about that part. So
Speaker 1: we're talking about having a programming language for DNA. But
Speaker 1: what good is that If you can write a program
Speaker 1: but you can't turn it into physical molecules, It's it's tough, right.
Speaker 1: So one of the things that we read about that
Speaker 1: I thought was so interesting was, um, some scientists were
Speaker 1: looking at the possibility of using different kim micle's while
Speaker 1: working with DNA and seeing how that would affect the process.
Speaker 1: And one person in this uh this group of researchers
Speaker 1: said we should really try cyanuric acid. And I knew him.
Speaker 1: Her issue ye a fellow of infinite jest. He used
Speaker 1: to clean my pool. The reason I say that is
Speaker 1: cyanuric acid is actually used by by people to to
Speaker 1: as a treatment for pools. Actually, yeah, it's a stabilizer.
Speaker 1: So you know you've heard about adding chlorine to pools
Speaker 1: so that you can make sure your your pool is
Speaker 1: not infest about it. I felt it in my eyeball. Well,
Speaker 1: cyanuric acid, what does It binds with chlorine and allows
Speaker 1: for a more controlled release of chlorine so that you
Speaker 1: don't just end up like deep shocking your pool and
Speaker 1: then you know, thirty minutes later it just becomes a
Speaker 1: bacterious cesspit that you don't want that to happen. But
Speaker 1: cian uric acid also has an effect on d N
Speaker 1: a uh. It actually can cause DNA to form into
Speaker 1: triple helix formations. The sin uric acid ends up becoming
Speaker 1: essentially a third rail of that ladder, and it then
Speaker 1: ends up having the other two sides bind with it.
Speaker 1: And this allows for the potential new use of DNA
Speaker 1: in various nanotechnology applications. At the moment, it's really early
Speaker 1: right now we know that this is the effect it
Speaker 1: can have on DNA. Where we can actually apply that
Speaker 1: knowledge remains to be seen. There are a lot of
Speaker 1: hopes that we can use this in multiple ways, but
Speaker 1: we're still kind of in the earliest days right now,
Speaker 1: so it's not like I have a practical application I
Speaker 1: can just spring out there. So that's sort of our
Speaker 1: our our kind of d N A one oh one,
Speaker 1: which has lots of open questions in it that are
Speaker 1: are currently being studied by people who are dedicating their
Speaker 1: lives to that kind of research. In our next episode,
Speaker 1: we're really going to look at how are we using
Speaker 1: DNA in practical applications today and how do we hope
Speaker 1: to use it in the future. Some of the ways
Speaker 1: apart from just using it to make our bodies right right,
Speaker 1: I mean we'll still be doing that fingers crossed. I'm
Speaker 1: not talking about like using it unconsciously. I mean, like
Speaker 1: consciously making use of as a technology, right, using DNA
Speaker 1: as a technology. So we're gonna really focus on that
Speaker 1: in our next episode. Guys. Remember if you have any
Speaker 1: suggestions for future episodes, we have questions or comments on
Speaker 1: things we've said, get in touch with us. Let us know.
Speaker 1: We love to hear from you. Guys. The address you
Speaker 1: can use if you want to use email is f
Speaker 1: W thinking at how Stuff Works dot com. Or you
Speaker 1: can drop us a line on social networks. We are
Speaker 1: on Facebook and Twitter. Twitter. We are FW thinking just
Speaker 1: search f W thinking on Facebook our profile pop up.
Speaker 1: You can leave us a message there, and we will
Speaker 1: talk to you again about DNA really soon. For more
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