Speaker 1: If you live in most places in the United States,
Speaker 1: mosquitoes are a massive annoyance.
Speaker 2: They've ruined a good hike, They've ruined a.
Speaker 1: Beautiful night camping under the stars, They've ruined delicious picnics,
Speaker 1: and they've ruin breathtaking sunsets.
Speaker 2: They are the worst.
Speaker 1: But if you live in an area where mosquitos carry
Speaker 1: deadly diseases like malaria, dengey, yellow fever, or zeka, they're
Speaker 1: also potentially deadly. According to the Centers for Disease Control,
Speaker 1: malaria alone killed five hundred and ninety seven thousand people
Speaker 1: in twenty twenty three.
Speaker 2: So what are our options.
Speaker 1: Mosquitoes have developed resistance to our insecticides, and insecticides in
Speaker 1: general aren't great for ecosystems because they often kill a
Speaker 1: bunch of other stuff as well. But what if we
Speaker 1: could use new genetic tools to drive some mosquito species
Speaker 1: to extend or make those mosquitoes resistant to diseases so
Speaker 1: they can no longer transmit those diseases to us. Today,
Speaker 1: we're going to respond to some listener questions about mosquitoes.
Speaker 1: We'll chat about how mosquitoes find us, how genetic engineering
Speaker 1: could be used to combat mosquitoes and how you undertake
Speaker 1: the tricky task of estimating how mosquito population sizes are
Speaker 1: changing over time. Welcome to Daniel and Kelly's Mosquito Infested Universe.
Speaker 3: Hi.
Speaker 4: I'm Daniel. I'm a particle physicist, and I have a
Speaker 4: top five list of animals i'd like to see genocided
Speaker 4: off the planet.
Speaker 1: Oh Man starting an episode with the word genocide.
Speaker 2: Not loving that. Hi, I'm Kelly Waiter Smith.
Speaker 1: I study parasites and space, and I was going to
Speaker 1: say I'm buzzing with enthusiasm for this topic, but Daniel
Speaker 1: started with genocides, So my enthusiasm has been shot through.
Speaker 4: Did that sting you a little bit? Scratching the wrong
Speaker 4: itch over there?
Speaker 2: I can't, I can't, I can't. All right, what are
Speaker 2: the five insects that you like the least, Daniel? We
Speaker 2: could put it that way too, you know.
Speaker 4: Yeah, number five mosquitoes, Number four mosquitoes, number three mosquitoes,
Speaker 4: number two mosquitoes, and number one coming in at the
Speaker 4: top of the list is mosquito.
Speaker 2: Yes, predictable list. Yeah. I'm not a mosquito fan really either.
Speaker 4: Absolutely, And so I'm fascinated today that we're going to
Speaker 4: be talking about the science of mosquitoes and learning about
Speaker 4: everything that biologists can do to improve our quality of life.
Speaker 1: Yeah, I'm a biologists and engineers. A variety of folks
Speaker 1: for many decades have been trying to do battle with mosquitoes,
Speaker 1: and you know, in the last few decades, we now
Speaker 1: have some genetic tools that we can use that might give.
Speaker 2: Us the leg up.
Speaker 4: And your focus, of course, is on eradicating disease, caring
Speaker 4: mosquitoes because that kills people and all that stuff and
Speaker 4: that along the way. Along the way, I would to
Speaker 4: eradicate Daniel's suffering from mosquito bites, because that's what it's
Speaker 4: really all about. In the end, It's about me and
Speaker 4: my itches.
Speaker 1: Right, No, i'd say no, Yeah, I don't actually know that.
Speaker 1: I would advocate for eliminating mosquitoes that are annoying but
Speaker 1: don't transmit disease, although I guess in California do do
Speaker 1: your mosquitoes transmit Wes Nile?
Speaker 4: I don't know. I have heard of cases, but I'm
Speaker 4: not sure. But really, for me, it's just all about
Speaker 4: the itches. I'm not a great sleeper and I'm very
Speaker 4: responsive to mosquito bites, which means if I get too
Speaker 4: many mosquito bites, then I'm up all nights scratching them.
Speaker 4: So it's really a bummer. I would happily actually donate
Speaker 4: my blood to the mosquitoes if we could make a deal,
Speaker 4: like if I could just put out a little like
Speaker 4: saucer of blood every night and be like, here's your
Speaker 4: blood meal, leave me alone. I would make that deal
Speaker 4: no trouble at all. So if the mosquito's lawyer wants
Speaker 4: to reach out and to go she ates some sort
Speaker 4: of settlement like that, I am open for business.
Speaker 1: All yes, So you give your fecal sample to your
Speaker 1: wife and your blood sample to the mosquitoes.
Speaker 2: Everybody needs a part of Daniel.
Speaker 4: Come take a sample exactly. Matt will take an audio sample.
Speaker 4: Here we go.
Speaker 2: All right.
Speaker 1: Well, then you will be very excited to hear today
Speaker 1: that there are a variety of cutting edge techniques for
Speaker 1: in some cases straight up eradicating mosquitos and in other
Speaker 1: cases just trying to make it so that they can't
Speaker 1: carry disease anymore.
Speaker 4: I like the sound a straight up eradication.
Speaker 1: Well, I reached out to our extraordinaries and asked them
Speaker 1: what they think the most promising techniques for eradicating disease
Speaker 1: carrying mosquitoes are and let's go ahead and hear what
Speaker 1: they had to say, treat.
Speaker 5: The water where they breed, kill the larvae.
Speaker 6: Someone far smarter than I am must have a technique
Speaker 6: to get them to stop breeding. I like what they've
Speaker 6: done in the past with releasing genetically modified ones so
Speaker 6: that it reduces the population and potentially targets those disease
Speaker 6: carrying ones, because the generic sprays kill all sorts of
Speaker 6: insects and they are beneficial for the ecosystem.
Speaker 7: Does the Geneva convention apply to mosquitoes? That does, I'd
Speaker 7: have to say some bioengineered aerosol that wouldn't harm other
Speaker 7: living creatures.
Speaker 8: The one technique I know right now is that some
Speaker 8: larvacide is spread during mosquito season. I'm not so sure
Speaker 8: that is the most promising technique, since that's been done
Speaker 8: for a long time and we still get a lot
Speaker 8: of mosquitos.
Speaker 9: It appears the sterile insect technique is the most promising method,
Speaker 9: though I'm not sure if that will eradicate or just
Speaker 9: vastly reduce population numbers, and is nowhere near as fun
Speaker 9: as an electrified racket swater.
Speaker 10: We would genetically engineer some very attractive but sterile mosquitos,
Speaker 10: dispatch them two the affected areas. Let dat run its course,
Speaker 10: and over time the population will fade away.
Speaker 11: Do the thing they're doing with the screw worms and
Speaker 11: doing like sterilized ones. And I really do hope that
Speaker 11: you kill all mosquitos, because they love me. I am
Speaker 11: foreign food here in the UK, even though I'm havy English,
Speaker 11: So kill them all.
Speaker 1: I think a lot of people are on the same
Speaker 1: page with you, Daniel eradicating mosquitos.
Speaker 2: They are on board.
Speaker 4: It sounds like somebody else spoke to the mosquito's lawyer
Speaker 4: because they're referencing the Geneva Convention and like getting illegal
Speaker 4: about it. Oh my gosh.
Speaker 1: I know, I know these things are intense well. And
Speaker 1: you know, in the United States, if you do want
Speaker 1: to release some method for eradicating mosquitos, you do need
Speaker 1: to go through like the USDA, the EPA. We'll talk
Speaker 1: about this a little bit more later. There's some legal
Speaker 1: stuff involved.
Speaker 4: I think that probably makes sense. Somebody should think about
Speaker 4: whether these are good ideas before we just like let
Speaker 4: scientists do things. Willy nilly, I'm for that.
Speaker 1: I'm gonna let you in on a little secret. We've
Speaker 1: messed things up a few times in the past.
Speaker 2: Yeah, I know, I know.
Speaker 4: Right now, we can't be trusted to make our own decisions.
Speaker 2: Well, I think some oversight is warranted.
Speaker 4: That's a good way to put it.
Speaker 2: We get a little over enthusiastic.
Speaker 4: Yeah, we knew because the universe is amazing and we
Speaker 4: just want to learn stuff and we think we have
Speaker 4: it figured out, and so yeah, we just want to
Speaker 4: press the big red button sometimes.
Speaker 1: Well, today we're going to be learning specifically about answers
Speaker 1: to questions that we got from listeners. And we called
Speaker 1: in a little bit of backup because any biology topic
Speaker 1: is improved by having Katrina Whiteson join the podcast. So
Speaker 1: let's invite Katrina on the show.
Speaker 4: It's my great pleasure to welcome back to the podcast,
Speaker 4: our most popular, our most frequent guest, also winner of
Speaker 4: the whites In Unable to Say No To a Podcast
Speaker 4: Invitation Award, doctor and Professor Katrina Whitson.
Speaker 5: Wow, thank you for the glamorous introduction.
Speaker 1: Thank you for being willing to come back on the
Speaker 1: show again. We always love having you.
Speaker 5: Well. Thanks all around, all right.
Speaker 2: Let's dive right in.
Speaker 1: So we have a couple questions from Robert Shackelford, who
Speaker 1: is a high school teacher who wanted to know about mosquito.
Speaker 2: Let's dive in.
Speaker 12: Hello, Daniel and Kelly, this is Robert on Samun Island
Speaker 12: in Washington State. And I'm curious about mosquitoes. Well, it's
Speaker 12: probably more accurate to say they seem to be curious
Speaker 12: about me, unfortunately. And where we live there's a pond nearby,
Speaker 12: and if you're anywhere near the pond, you will get
Speaker 12: bidden right away. Further from the pond, it's not so
Speaker 12: bad unless you're stationary, and then they will find you.
Speaker 12: And when they find you, they really find you. And
Speaker 12: that has me wondering if they are coordinating their attack somehow,
Speaker 12: if they are watching each other, or if they are
Speaker 12: our little mosquito walkie talkies I don't know, or they're
Speaker 12: just acting individually on the same clues to find the victim.
Speaker 12: And then similarly, I would love to know how many
Speaker 12: mosquitoes I'm up against, right, it's important.
Speaker 4: To know your enemy.
Speaker 12: And how would you ever estimate a mosquito population? I
Speaker 12: know there's some techniques for estimating wildlife, say birds, by
Speaker 12: tagging them and then recapturing them later, But I can
Speaker 12: imagine doing that with mosquitos. Sorry, Kelly, I can't imagine
Speaker 12: even the best biologist having the ability to take little
Speaker 12: tag number forty two and glue it to a mosquito's
Speaker 12: leg and be able to capture it later. So I'm curious.
Speaker 12: Is there a way Is that number even that knowable?
Speaker 12: Is there a way to make a good estimate of
Speaker 12: mosquito population? Really curious? Thank you so much for taking
Speaker 12: on my question. Look forward to hearing from you soon.
Speaker 4: Wonderful question. I love hearing from high school teachers, and
Speaker 4: thank you to all the teachers out there working on
Speaker 4: the front lines of education to make society a better
Speaker 4: place than everybody smarter.
Speaker 2: You all are heroes.
Speaker 1: Thank you so much, And I am thrilled to get
Speaker 1: to educate folks about mosquitos, which I have to admit
Speaker 1: I hate.
Speaker 4: It's not hard to admit you hate mosquitos. It's joyful.
Speaker 1: I guess don't know how many collegist I'm supposed to
Speaker 1: like almost everything, but I have to admit dipterines, which
Speaker 1: are like mosquitos and flies, I'm not a big fan
Speaker 1: of well.
Speaker 4: You know, I used to say all the time that
Speaker 4: mosquitos are the one thing you could like erase from
Speaker 4: the planet and not have any negative effects. But then
Speaker 4: some listeners sent me an article about how mosquitos helped
Speaker 4: chocolate help cocoa beans pollinate each other, and I was like, uh, oh,
Speaker 4: I'm not sure if I had to give up mosquitos
Speaker 4: if I would also give up chocolate.
Speaker 1: It sounds a little bit tough at first, but when
Speaker 1: you consider that mosquitoes transmit malaria, which kills almost six
Speaker 1: hundred thousand people a year, I would give up chocolate
Speaker 1: for that.
Speaker 4: I mean, I hear you, But we're talking about chocolate here, Kelly.
Speaker 2: We're talking about children, Daniel.
Speaker 1: But I have to remember that you are willing to
Speaker 1: give up all of humanity to get one answer from
Speaker 1: an alien.
Speaker 2: We had that discussion the.
Speaker 4: Other that juicy answer. But yes, yes, I am, that's true,
Speaker 4: all right.
Speaker 1: I'll note that his wife was also shaking her head
Speaker 1: in disbelief.
Speaker 4: I don't like this new number of podcast hosts where
Speaker 4: I can get outvoted.
Speaker 2: We'll go back to mosquitoes.
Speaker 1: Mosquitos are often enlisted as the deadliest animals on the
Speaker 1: planet Wow. And one of the problems caused by mosquitos
Speaker 1: is that they transmit malaria. There are over five hundred
Speaker 1: Anoplies mosquito species, so this is like a genus of mosquito,
Speaker 1: and about sixty of those species are able to transmit malaria.
Speaker 1: Mosquitos also transmit Dangae west Niles zega lymphatic philoriasis, and
Speaker 1: so mosquitoes are estimated to kill indirectly up to a
Speaker 1: million people a year. But I've never felt like this
Speaker 1: is super fair to pin on mosquitos, even though I
Speaker 1: hate mosquitoes, because it's like, isn't it the individual responsibility
Speaker 1: of all of those diseases. It's not necessarily the mosquitoes.
Speaker 1: But I get I get it.
Speaker 13: They were unwilling partners. Nobody like, they didn't say, yeah,
Speaker 13: bring on that plasmodium. They were just like flying a rods.
Speaker 13: But they do drink blood. I mean, I don't know.
Speaker 4: I mean, Kelly, if I came over to your house
Speaker 4: and drank your blood and give you some weird disease,
Speaker 4: I think you'd blame me for anything you got, wouldn't you?
Speaker 2: You wouldn't be invited again. That's true.
Speaker 1: And you would be breaking a lot of social wars
Speaker 1: to do that, and laws and laws and laws. Right,
Speaker 1: But does anybody want to guess? This surprised me a little,
Speaker 1: But it shouldn't have. On the list of species that
Speaker 1: kill humans, mosquitoes are at the top. What species is second?
Speaker 1: The next most killing e species kills about half as
Speaker 1: many humans each year. But what would you guess? That
Speaker 1: species is?
Speaker 4: Raccoons? Those are ferocious? Have you heard that story about raccoons?
Speaker 4: Don't have a pet raccoon? FYI, and don't google what
Speaker 4: happens if you lead a raccoon in a room with
Speaker 4: your baby.
Speaker 5: Oh, definitely don't google that.
Speaker 13: But I would guess it's microbial. I mean, it has
Speaker 13: to be microbial. Microbes rule the world. So now I've
Speaker 13: got to like pick from microbes, and I really should
Speaker 13: know this.
Speaker 5: I mean, it could be tuberculosis.
Speaker 2: Bacteria that is still a problem which.
Speaker 5: Infects a third of humans. Or it could be real raccoons,
Speaker 5: my gosh.
Speaker 13: Some kind of parasite, some kind of eukaryotic parasite.
Speaker 5: Is that what it is?
Speaker 2: It's humans?
Speaker 5: Oh my god?
Speaker 2: Oh that's so good.
Speaker 4: I think Katrina gets points because we are eukaryotic parasites, right,
Speaker 4: So there you go.
Speaker 1: There you go point So Katrina essentially got it right.
Speaker 1: One point for Katrina, zero points for raccoons.
Speaker 13: From Daniel, I'm not gonna I can't take any points.
Speaker 13: I was going down a totally wrong road there, and
Speaker 13: I really thought it was my crogial, you know.
Speaker 1: I also felt like you could just blame bacteria across
Speaker 1: the board. But anyway, the list right now has humans.
Speaker 1: I guess we kill about half a million of each
Speaker 1: other every year, which is depressing.
Speaker 2: Wow.
Speaker 1: But all right, let's talk about the mosquito life cycle
Speaker 1: real quick, because understanding the life cycle is necessary if
Speaker 1: you're going to understand how you can try to eradicate
Speaker 1: mosquitos by breaking part of the life cycle.
Speaker 2: So first, let's note.
Speaker 1: There's lots of mosquito species, like over three thousand, five
Speaker 1: hundred mosquito species. They don't all bite humans. The ones
Speaker 1: that you bite humans are females. The males actually don't
Speaker 1: take blood meals, and the females apparently need the blood
Speaker 1: to make eggs. Okay, so if you get bit it's
Speaker 1: a female, don't blame the female. They're just doing what
Speaker 1: evolution made them. Do but anyway, so they do the
Speaker 1: blood meal. So they get a blood meal, they lay
Speaker 1: their eggs in a body of water, the eggs hatch
Speaker 1: in the water, and then they've got this aquatic stage
Speaker 1: where they look like these sort of like frilly little
Speaker 1: specks of dirt that kind of move around like crazy
Speaker 1: all over the place. Sometimes you might see them in
Speaker 1: like a bird feeder in the middle of the summer
Speaker 1: or something. And then they have another stage where they
Speaker 1: essentially like stay near the surface and they're kind of
Speaker 1: getting oxygen from the surface. And then they emerge out
Speaker 1: of the aquatic environment as adults and they go off
Speaker 1: and you know, mate with each other and go off
Speaker 1: in search of blood.
Speaker 4: And all this happens in hours or days.
Speaker 1: Or depends on the species. There's a lot of variability,
Speaker 1: but an egg can take something like seven to ten
Speaker 1: days to develop into an adult, and then when they're
Speaker 1: an adult, I think they've got like a week or
Speaker 1: a few weeks. They don't live for very long, so.
Speaker 4: When a mosquito is biting you, it's like one of
Speaker 4: a few dozen meals it's gonna have in its lifetime,
Speaker 4: or how many blood meals does a mosquito have in
Speaker 4: their whole lifetime.
Speaker 1: They must be taking more than one blood meal. But
Speaker 1: I think they only mate with a male once in
Speaker 1: their life and lay eggs once, and that has to
Speaker 1: be the case for a bunch of the techniques that
Speaker 1: we talk about later to work.
Speaker 4: Well. I know that in southern California we have two
Speaker 4: different kinds of mosquitos. So the ones that come and
Speaker 4: give you one really big juicy bite and then move on,
Speaker 4: and another tiny version that come in bye you like
Speaker 4: four times in a row.
Speaker 2: Oh they're all awful.
Speaker 4: Though, they're all awful.
Speaker 1: Yeah, thumbs down. Well, so then how do they find you?
Speaker 1: So Robert wanted to know if they're like communicating with
Speaker 1: each other so that they can swarm and get to you,
Speaker 1: and I don't think that that's what's happening. I didn't
Speaker 1: find any evidence that a mosquito is like altruistic enough
Speaker 1: to be like, hey, there's a snack over here, fellas,
Speaker 1: or I guess, ladies, Hey, ladies, there's a snack over here,
Speaker 1: because it's all females do in the feeding. I think
Speaker 1: that the only times they swarm on purpose is when
Speaker 1: they're trying to mate, and so usually they're not sharing information.
Speaker 1: But the way they find you is a multi step process. First,
Speaker 1: they detect the carbon dioxide that we breathe out, and
Speaker 1: then they follow the carbon dioxide trail until they get
Speaker 1: close to us. When they start getting close enough to us,
Speaker 1: they start detecting some odors that we give off. And
Speaker 1: these odors can be things like ketones, lactic acids, and Katrina,
Speaker 1: I read that a lot of the odors we give
Speaker 1: off are related to our microbiome exactly.
Speaker 13: I even had a whole grant once. I didn't get it,
Speaker 13: but I wrote a grant with a bunch of people.
Speaker 13: It was a military grant, and the goal was to
Speaker 13: make soldiers invisible to mosquitoes. And you're going to do
Speaker 13: it by changing their skin microbiomes. And you know, some
Speaker 13: people are just so juicy to mosquitos and they get
Speaker 13: bitten all the time and others don't. And we don't
Speaker 13: know why really, but I think it could be related
Speaker 13: to the microbiome and the volatiles that the microbes are
Speaker 13: emitting that the mosquitoes can detect, and so anyway, it
Speaker 13: might be that that's something we can change.
Speaker 5: Like, that's pretty amazing.
Speaker 4: Hold on a second, I just put two and two together.
Speaker 4: I live in a house where I'm the one getting
Speaker 4: bitten by mosquitoes all the time, and I also live
Speaker 4: in a house where somebody knows how to manipulate people's microbiomes.
Speaker 4: And I just heard that microbiomes are the number one
Speaker 4: influence and who gets bitten by mosquitoes? Hmm, Okay, I'm
Speaker 4: gonna have to think about that.
Speaker 13: Okay, This mosquito preference thing has been going on since
Speaker 13: way before I learned about microbiomes.
Speaker 4: I see, so you've been guilty for a long time,
Speaker 4: got it, got it all right?
Speaker 5: But it could be a life goal.
Speaker 4: But for the individual mosquito, Kelly, this is not, like
Speaker 4: you know, they have complicated sensors. I'm imagining they're like
Speaker 4: flying through the air and they sort of veer towards
Speaker 4: the CO two instead of away from it. It's sort
Speaker 4: of like moths being attracted to light. Is that how
Speaker 4: it works?
Speaker 2: Yeah?
Speaker 1: I mean I think it might be under selling it
Speaker 1: a little bit to say that they don't have complicated sensors.
Speaker 1: So like moths, for example, the males who have to
Speaker 1: find the females, they have super feathery antenna and nobody
Speaker 1: can see.
Speaker 2: But I have hand antennas right now.
Speaker 4: You're looking very mathia, I thank.
Speaker 2: You, thank you.
Speaker 1: And they, you know, have an incredible surface area, and
Speaker 1: they're able to detect chemicals that the females put into
Speaker 1: the environment and follow that chemical trail to find a female.
Speaker 1: And so, you know, like insects, they you know, they
Speaker 1: might not look super impressive, but they do have pretty
Speaker 1: impressive ways of detecting cues in the environment. Like I
Speaker 1: can't detect CO two and use it to find my
Speaker 1: dog when she's not coming in the middle of the
Speaker 1: night when I call her. So anyway, I'm impressed. But yeah,
Speaker 1: it's not super complicated.
Speaker 13: I mean, I think there's a lot of sensors that
Speaker 13: we actually don't know what they are. That's something that
Speaker 13: I'm so fascinated by that apparently, you know, we have
Speaker 13: these sensory receptors that we know about in our nose
Speaker 13: and our tongue, like you hear about the sense of taste,
Speaker 13: But actually we have those kind of receptors all.
Speaker 5: Over the place.
Speaker 13: They're in our skin, they're in our guts, like babies
Speaker 13: have them when they're developing, and so I think those
Speaker 13: receptors are binding molecules we don't even know what they
Speaker 13: are yet, and I would not be surprised the mosquitoes
Speaker 13: have a lot of that going on.
Speaker 4: You're saying we can taste with our hands and stuff
Speaker 4: like that, exactly. I see. So when I swat a
Speaker 4: mosquito and I feel that like moment of satisfaction, it's like,
Speaker 4: literally delicious.
Speaker 5: Let me just back up on that.
Speaker 13: I'm saying, there's receptors that are sensing those molecules and
Speaker 13: you're having a response. The response is not lighting up
Speaker 13: the taste receptors in your brain, at least.
Speaker 2: Not for me.
Speaker 13: I mean, I don't know about you, but I think
Speaker 13: it's like lighting up something that not necessarily that we're
Speaker 13: even aware of it in our brain, but it could
Speaker 13: be like affecting our physiology.
Speaker 5: You know.
Speaker 1: We had Stephen Munger on the show to talk about
Speaker 1: taste and smell, and he was talking about how we
Speaker 1: have receptors for things like even in our hearts, and
Speaker 1: it's not quite clear why we have them. So if
Speaker 1: folks want to learn more about that, they should check
Speaker 1: out the Manger episode because we talk about that for
Speaker 1: a little bit. It's totally fascinating in my opinion.
Speaker 4: All Right, so, but we were talking about how mosquitoes
Speaker 4: find hosts, and you're saying, at first they look for
Speaker 4: clouds of CO two, and then as they get closer,
Speaker 4: they're looking for skin odorans that give them cues to
Speaker 4: where you are, and then what walk us through through
Speaker 4: all the way to the bite.
Speaker 1: And then they're looking for heat and humidity. And so
Speaker 1: I don't think we know exactly how they decide, like
Speaker 1: I'm going to bite their arm as opposed to their leg.
Speaker 1: It might be whatever they encounter first, because you want
Speaker 1: to get the bite in there and get out. But yeah,
Speaker 1: those are the cues that they use. The cues change
Speaker 1: depending on how close they are to us. Some people
Speaker 1: give off more cues, as Katrina mentioned, that could be
Speaker 1: because of their microbiome. There's some evidence that women in
Speaker 1: their third trimester are also more attractive to mosquitoes. And
Speaker 1: the idea there is that we are breathing more and
Speaker 1: more heavily and we give off more CO two, so
Speaker 1: we're easier for mosquitos to find. I certainly was breathing heavily.
Speaker 1: I remember my mom being like, do you have to
Speaker 1: be so loud?
Speaker 2: And I was like I do. I'm breathing for two.
Speaker 8: Uh.
Speaker 1: But yeah, the mosquitoes apparently love that. All right, So
Speaker 1: now we know how mosquitoes find us, But now how
Speaker 1: do you figure out how many mosquitoes are in an area?
Speaker 1: So Robert had this great insight, which is that often
Speaker 1: when we are trying to faitigure out how many of
Speaker 1: a certain species is in a particular environment, we use
Speaker 1: this technique called mark recapture, and it would be really
Speaker 1: hard to mark and recapture mosquito. So mark recapture is
Speaker 1: a procedure where you essentially go out into an environment
Speaker 1: twice to collect animals. The first time you go out,
Speaker 1: you collect you know, as many animals as you can
Speaker 1: with whatever technique. So, for example, I used to go
Speaker 1: sample fish and I would use what's called fight nets.
Speaker 1: You essentially put a net that goes one side of
Speaker 1: it is in like the middle of a lake. The
Speaker 1: other side goes to the shoreline. As the fish swim
Speaker 1: along the shoreline, they hit the net that hits the
Speaker 1: shoreline and they follow it essentially into a funnel that
Speaker 1: they can't get out of. And then you sample that
Speaker 1: once a day. Does that make sense mm hm? Okay,
Speaker 1: So we trap fish, we take the fish out, we
Speaker 1: tag the fish in a way where we will know
Speaker 1: if we've seen them before or not, and then we
Speaker 1: release them back into the environment. And then a week
Speaker 1: or two later, we go out again and we use
Speaker 1: another technique to catch as many fish as we can.
Speaker 1: In this case, we're using an electro fishing boat where
Speaker 1: you stun the fish temporarily, you bring them into a
Speaker 1: live well on the boat where it's got a lot
Speaker 1: of water circulating so that they can come to and
Speaker 1: stay safe. And then you count how many fish you collected,
Speaker 1: and you look to see how many of them you're
Speaker 1: catching for the second time, so how many of them
Speaker 1: showed up in both of your samples, And so then
Speaker 1: you're making this assumption that the proportion of animals that
Speaker 1: you re caught in your second sample is similar to
Speaker 1: the proportion of animals that you caught the first time
Speaker 1: in the entire population. So, for example, if I caught
Speaker 1: fifty fish in my first sample and marked them all,
Speaker 1: and then I went out and I caught one hundred
Speaker 1: fish in my second sample, ten of which were already
Speaker 1: marked individuals, the way that I would capture this is
Speaker 1: I would say fifty times one hundred which is the
Speaker 1: number of fish I captured in both of my samples,
Speaker 1: and divide by ten, which is the number of individuals
Speaker 1: I caught twice, and that would give me an estimate
Speaker 1: that there's five hundred fish in the population, all right.
Speaker 4: So the goal here is to get a sense for
Speaker 4: how many animals there are total. Of course, you can't
Speaker 4: measure all of the animals, and so you measure twice
Speaker 4: and then you look at the overlap because like, if
Speaker 4: you have one hundred percent overlap between your two measurements,
Speaker 4: that means you have a smaller population. If you have
Speaker 4: no overlap between your two measurements, then you have a
Speaker 4: bigger population because you're getting like different subsets of the
Speaker 4: whole population. Is that the way to think.
Speaker 2: About it exactly?
Speaker 13: Yes, Yeah, Like if you mark one hundred fish and
Speaker 13: then the next day every single fish is marked, it
Speaker 13: suggests there's not really any other fish out there. But
Speaker 13: if only ten percent of them are marked, then it
Speaker 13: suggests that the population has another ninety percent out.
Speaker 4: There, right, cool, all right, So that's how mark and
Speaker 4: recapture studies work to get a sense for like how
Speaker 4: many birds are there, or how many cheetahs are there,
Speaker 4: But what do you do for mosquitoes. You can't capture
Speaker 4: and mark mosquitoes, can you.
Speaker 1: So first of all, thanks team, it was very helpful
Speaker 1: to have your input on that. Yeah, so marking and
Speaker 1: recapturing mosquitoes would be kind of nuts because they're so
Speaker 1: small and so delicate that when you go to catch
Speaker 1: them and count them, unfortunate, well maybe not unfortunately, you
Speaker 1: usually kill them in the process of counting them. And
Speaker 1: so how could you mark a mosquito and release it?
Speaker 1: And the answer is they usually don't. So when a
Speaker 1: lot of companies are trying, for example, to see how
Speaker 1: many mosquitos are out there, what they'll do essentially is
Speaker 1: grow males in the lab and they'll throw out all
Speaker 1: of the females because you don't want to put any
Speaker 1: extra mosquitos out there that will be biting anybody and
Speaker 1: taking blood meals. But since the males don't take blood meals,
Speaker 1: they hatch them out of eggs in the lab, and
Speaker 1: then when they go to emerge to go from the
Speaker 1: water to their like air phase, they put a powder
Speaker 1: on the surface of the water and it's a fluorescent powder,
Speaker 1: so as the mosquitoes emerge through it they get covered
Speaker 1: in this fluorescent dust.
Speaker 4: Wow, and you get fabulous mosquitos.
Speaker 2: And you get fabulous mosquitos.
Speaker 1: You can also genetically modify them so that they fluoresc
Speaker 1: green based on a protein that they're making themselves. But
Speaker 1: one way or another, you're making it so that the
Speaker 1: animals that you've released into the wild are detectable in
Speaker 1: some way that it didn't require you to like handle them,
Speaker 1: which could kill them. So now instead of doing mark
Speaker 1: and recapture, you mark in the lab and then when
Speaker 1: you go out you can put, for example, a giant
Speaker 1: tub with dry ice which releases CO two that attracts
Speaker 1: the mosquitoes, and so you find a way to capture them.
Speaker 1: And then you look at the proportion of mosquitos that
Speaker 1: you recapture that fluores when you look at them, and
Speaker 1: you'll say, okay, those are the ones we added to
Speaker 1: the environment from the lab. And then you compare that
Speaker 1: to the number that didn't fluoresse, which were the wild
Speaker 1: animals that you're catching for the first time. And this
Speaker 1: process does kill them while you're doing the counting. Does
Speaker 1: that make sense?
Speaker 4: Yes, So if you attract and capture a bunch of
Speaker 4: mosquitos and they're all your fluorescent ones. It suggests that
Speaker 4: your fluorescent ones are dominating the population. And if they
Speaker 4: come back and you see almost none of your fluorescent ones,
Speaker 4: it means that there are a tiny fraction of the population.
Speaker 4: So there's a bunch out there. Exactly what I wonder is, like,
Speaker 4: how many other crazy ideas did they come up with
Speaker 4: before this crazy idea that they made work. I love
Speaker 4: the experimental creativity of science this way, you know.
Speaker 3: Like this is a hilarious idea, But I would really
Speaker 3: love to see the whiteboard where they came up with
Speaker 3: all sorts of bizarre ideas, including like you know, laser
Speaker 3: pointers or who knows what.
Speaker 1: There are some more complicated methods, so for example, you
Speaker 1: can like look at how many batches of eggs appear
Speaker 1: to have been laid in like some water that you
Speaker 1: put out, and then you can try to extrapolate from
Speaker 1: the batches of eggs how many females likely came by
Speaker 1: to lay those eggs. And it's much more complicated and
Speaker 1: there's a lot more guesswork because you have to like
Speaker 1: have an estimate for the average number of eggs laid
Speaker 1: by a female, for example. But yes, I think it
Speaker 1: is a beautiful technique to release fluorescent mosquitoes who can't
Speaker 1: bite you and then see how many of them you
Speaker 1: get back.
Speaker 4: And this is important because it's like a basic element
Speaker 4: of mosquito science. It just like to know what are
Speaker 4: the populations and where are they, right, because without basic
Speaker 4: knowledge you can't do anything. But I think a lot
Speaker 4: of people underest to me, like how much work goes
Speaker 4: into just getting some basic information. Like we had our
Speaker 4: episode about weather, and like just knowing what is the
Speaker 4: temperature everywhere on the Earth would be hugely helpful, and
Speaker 4: we can't know that. We don't know that, and so
Speaker 4: just like knowing where the mosquitoes are would be massively beneficial,
Speaker 4: I imagine.
Speaker 2: Yeah.
Speaker 13: And actually, I don't know if you guys have ever
Speaker 13: talked about the citizen science projects that are the reason
Speaker 13: we have information about insect population size. But for example,
Speaker 13: many of us have noticed that our windshields are not
Speaker 13: covered in bugs when we go on a read trip
Speaker 13: these days, and that's because the insect populations have declined
Speaker 13: so much. And there are citizen science projects where people
Speaker 13: will like put nets kind of like the one you
Speaker 13: described on the top of their cars and drive around
Speaker 13: and just catch all the insects and count them. And
Speaker 13: there were people that were doing that in Germany throughout
Speaker 13: the twentieth century, and that is a big part of
Speaker 13: why we know about the insect decline. Like if they
Speaker 13: hadn't done that, we just wouldn't even know.
Speaker 2: Wow, I didn't know about that.
Speaker 4: Yeah, that's amazing. Thank you. Weird German insects capture people.
Speaker 4: There are people out there who have enthusiasm for everything.
Speaker 4: It's incredible. Yes, well, I need a break from all
Speaker 4: of these mosquitoes. I gotta go scratch some itches and
Speaker 4: when we come back, we're going to talk more about
Speaker 4: how mosquitoes do what they do and how we do
Speaker 4: what we do best, which is kill mosquitoes. Wow.
Speaker 12: Thank you for those answers, Daniel and Kelly. What are
Speaker 12: relief knowing that mosquitoes aren't able to coordinate their attacks?
Speaker 12: Let's hope they do not evolve that ability anytime soon.
Speaker 12: Also so amazed that biologists have figured out a way
Speaker 12: to estimate mosquito populations. Sorry, Kelly, I will never doubt
Speaker 12: biologists again. Let's get whoever came up with that idea
Speaker 12: working on quantum gravity soon. Love the show. Thank you,
Speaker 12: guys so much. Shout out to my Spring Street students.
Speaker 4: Okay, we're back and I'm very excited for this segment
Speaker 4: of the podcast where we get to take scientific revenge
Speaker 4: on all the mosquitoes that have caused me to suffer
Speaker 4: so much.
Speaker 1: All right, so we have this question from a listener, James,
Speaker 1: and let's go ahead and listen to James's question.
Speaker 14: Hi, Daniel and Kelly, I was wondering if you could
Speaker 14: cover gene drives. It seems like this technology has been
Speaker 14: out for a long time but hasn't been deployed. It
Speaker 14: seems like a magical technology for wiping out invasive species.
Speaker 14: When you have invasive mosquitoes wiping out the last native
Speaker 14: Hawaiian songbirds with av and malaria, you have to ask
Speaker 14: why you wouldn't test this out on such isolated islands.
Speaker 14: What terrifying scenarios are keeping them from deploying gene drives
Speaker 14: in the outside world. Are those scenarios realistic or is
Speaker 14: the pesticide industry just bumping off gene drive researchers.
Speaker 1: Thanks, all right, So we have tried lots of things
Speaker 1: to kill mosquitoes with varying success.
Speaker 2: One of the things we tried.
Speaker 1: Initially was spraying a bunch of insecticides, and that worked
Speaker 1: for a while, but eventually the mosquitoes that happened to
Speaker 1: be resistant to the insecticides had a lot more babies.
Speaker 1: And now we have populations of insecticide resistant mosquitos.
Speaker 4: How does that even possibly work? I mean, I see
Speaker 4: like trucks driving around spraying insecticide, but I'm like, you know,
Speaker 4: what fraction of the mosquitoes are they going to be
Speaker 4: hitting with that? It seems like, you know, shooting individual
Speaker 4: pigeons in the park or something.
Speaker 1: It's like hopeless, right, Yeah, And sometimes they release it airborne.
Speaker 1: Other times they'll specifically release insecticides into like waterways where
Speaker 1: mosquitoes are breeding, and that's a little bit more targeted.
Speaker 1: Either way, you're probably killing a bunch of stuff you
Speaker 1: don't intend on killing as well, because a lot of
Speaker 1: these things are not specific just for mosquitoes.
Speaker 4: And then aren't people going to end up drinking insecticide?
Speaker 2: Yeah, or breathing it in?
Speaker 1: I remember whenever the insecticide trucks would come through in California,
Speaker 1: I would run inside the house or I'd bring my
Speaker 1: baby inside of the house. And yeah, so you breathe
Speaker 1: it in presumably. I mean they try to make it
Speaker 1: so that these chemicals are specifically focusing in on things
Speaker 1: mosquitoes and other insects do and not things that happen
Speaker 1: inside the human body. I don't know how well we're
Speaker 1: often able to do that, Katrina, do you have any
Speaker 1: insights there?
Speaker 13: Yeah, oh, exactly, that's the idea, But I think that's
Speaker 13: extremely hard. I mean, when it comes to viruses and microbes,
Speaker 13: it's easier to come up with targets that are totally
Speaker 13: orthogonal to what would happen to a person, But that's
Speaker 13: so much harder for insects.
Speaker 5: Like we're a little more closely related, believe it or not.
Speaker 4: To insects than we are to microbes.
Speaker 13: Yeah, yeah, exactly, so it's harder to come up with
Speaker 13: distinct targets.
Speaker 5: But yeah, that's definitely the goal.
Speaker 13: But I think there's all kinds of off target impacts.
Speaker 13: Like I'm sure you guys remember hearing about the Peregon
Speaker 13: falcons and the compromised egg structure that came from all
Speaker 13: the insecticides being sprayed in the sixties.
Speaker 1: Yeah, right, the DDT. Yeah, I think Rachel Carson wrote
Speaker 1: about that in silent spring. Yes, So we use these insecticides,
Speaker 1: and we're trying to use them in a little bit
Speaker 1: more specific ways. So, for example, you can dip a
Speaker 1: bed net in insecticides, and then you can put the
Speaker 1: bed net over your bed and then at the time
Speaker 1: of day when mosquitos are most likely to bite, you're
Speaker 1: protected inside of the bed net, and because it has
Speaker 1: already soaked into the bed net, you're not breathing a
Speaker 1: lot in or you're not drinking it in water. But
Speaker 1: the problem is that there's very strong selection pressure for
Speaker 1: mosquitoes to find routes around this. So, for example, if
Speaker 1: you've got mosquitos that bite at night, if there's variability
Speaker 1: and some mosquitoes are biting a little bit earlier in
Speaker 1: the day, the ones that bite earlier in the day
Speaker 1: are going to catch the early birds and then they're
Speaker 1: going to have a lot more babies that go early
Speaker 1: in the day. And now the bed net isn't as helpful.
Speaker 1: And we've actually been finding that in some parts of
Speaker 1: the world mosquitos are changing there the time of day
Speaker 1: when they're most active, so that they are now going
Speaker 1: after people when they're outside of the bed nets.
Speaker 4: Wow, And this is why when I came back from
Speaker 4: a trip to Tahiti where we had to sleep with
Speaker 4: bed nets every night, and I loved waking up without
Speaker 4: any bites. I just set up the bed net on
Speaker 4: our couch and then for weeks, I just like, anytime
Speaker 4: I'm hanging on the couch, I'm under the mosquito net.
Speaker 4: No big deal. I'm like impervious. I'm like laughing at
Speaker 4: all the mosquitoes.
Speaker 2: Ha ha.
Speaker 13: It was a very interesting sight, Daniel, Like watching TV
Speaker 13: while sitting inside the bed net.
Speaker 4: It's amazing, amazing because I don't feel any social pressure
Speaker 4: to be bitten by mosquitos, so I don't look like
Speaker 4: a weird under a bench. I was happy. It was great,
Speaker 4: and now I know that ecologically I was, you know,
Speaker 4: suppressing mosquitos in a balanced way. So yeah, I was
Speaker 4: being responsible.
Speaker 2: Way to go, Daniel, Thank you, pat on the back.
Speaker 4: All right, that's what I wanted. Thank you very much.
Speaker 1: So mosquitos essentially are constantly providing a moving target where
Speaker 1: there's selection for them to route around whatever methods that
Speaker 1: we are using to try to keep them at bay.
Speaker 1: People also use things like they'll dump mosquitofish into waterways.
Speaker 1: These are tiny little fish that eat the aquatic stages
Speaker 1: of the mosquito.
Speaker 4: My new favorite fish.
Speaker 1: Yeah, But then the problem is they also out compete
Speaker 1: a bunch of native fish, and they cause problems in
Speaker 1: the ecosystems that you introduce them in because they're not
Speaker 1: native there. So it's not a perfect method, but it's
Speaker 1: a method you can use in some areas at your
Speaker 1: own house. Now that you know that there's an aquatic stage.
Speaker 1: Maybe you already knew that, but you can make sure
Speaker 1: that you dump any standing water and if you want to,
Speaker 1: like have a bird bath, just dump it out every
Speaker 1: day or two and then refill it because that won't
Speaker 1: give the mosquitos time to hatch. But trying to like
Speaker 1: up the complication level a little bit. The next thing
Speaker 1: that we started in the nineteen fifties was using sterile
Speaker 1: insect technique, and folks might remember that we talked about
Speaker 1: this a bit for the screwworm episode, and the idea here,
Speaker 1: essentially is that you blast mosquitoes with gamma rays or
Speaker 1: other chemicals that sterilize them, and then you release just
Speaker 1: the males into the environment. Female mosquitos mate once and
Speaker 1: they'll mate with one of these sterile males, and then
Speaker 1: if they're able to lay eggs, those eggs won't hatch,
Speaker 1: And so essentially you are taking females out of the
Speaker 1: population reproductively by having them mate with males where it
Speaker 1: won't result in successful offspring. But this method has a
Speaker 1: couple problems. First of all, if you are just like
Speaker 1: randomly bombarding insects with gamma rays, yes you're gonna sterilize them,
Speaker 1: but you also might beat them up in a bunch
Speaker 1: of other ways. And so sometimes these males that you
Speaker 1: release into the environment aren't as good at attracting the
Speaker 1: ladies as the wild males, because these males have all
Speaker 1: sorts of other things wrong with them.
Speaker 4: Since Kelly, I read a bunch of comic books, and
Speaker 4: if you blasphamilar with gamma rays, it usually gives it superpowers. Right, Yeah,
Speaker 4: are you telling me that particle physics isn't really connecting
Speaker 4: with the biology there? Is that what's happening?
Speaker 1: I think that's what's happening, Daniel. I'm really sorry. Or
Speaker 1: maybe it's a statistical thing. Sometimes it works out that way.
Speaker 1: But the mosquitos just they there hasn't been the Spider
Speaker 1: Man equivalent for mosquitoes yet.
Speaker 4: Yeah, I'm glad that we haven't turned any of these
Speaker 4: mosquitoes into the incredible hulk mosquito. Yeah, that would be
Speaker 4: really excite to see that.
Speaker 2: It would be mad.
Speaker 5: Yeah, I bet the fabulous mosquitos do great though.
Speaker 4: Yeah.
Speaker 13: And actually I have a colleague at the City of
Speaker 13: Hawaii who's working on the microbiome. It's actually in the
Speaker 13: context of gene drives, but they are working on making
Speaker 13: the microbiome of the mosquitos robust to help the mosquitos
Speaker 13: that they're engineering to go out there and succeed with
Speaker 13: the ladies.
Speaker 5: As it were.
Speaker 2: Nice. Is this Wallbakia, No, it's mosquitos.
Speaker 5: It's a malaria project.
Speaker 13: It's Nicole Hinson at the University of Hawaii by Walbakia.
Speaker 1: I meant the bacteria that they're adding. But anyway, we'll
Speaker 1: get back to Wallbachia.
Speaker 13: So no, I think that they are like more roundly
Speaker 13: making the microbiome of the mosquito robust, so that in
Speaker 13: general the mosquito is robust.
Speaker 4: I'm not sure, but again with this method, I wonder, like,
Speaker 4: how many males do you have to put out there
Speaker 4: to have this have any efficacy. It's not like the
Speaker 4: males are reproducing and making more of themselves, right, so
Speaker 4: like every one you put out, it's one that you
Speaker 4: essentially manufactured. Is it really possible to have an impact
Speaker 4: on the population.
Speaker 1: Yeah, great question. So there was an experiment done in Havana, Cuba.
Speaker 1: Sorry I said that wrong, but that's what we expect
Speaker 1: out of me. Where about one and a quarter million
Speaker 1: or radiated mosquitos in this case, the species was eighties
Speaker 1: jipdi were released and again all males, and they did
Speaker 1: a twenty week trial and they looked at a fifty
Speaker 1: hectare area, so a pretty big area, and they put
Speaker 1: out what they called ovtraps, essentially just like areas where
Speaker 1: mosquitoes could lay eggs, and they didn't find any eggs
Speaker 1: in that fifty hectar area, suggesting that one in a
Speaker 1: quarter million mosquitoes, which is a lot of mosquitoes, is
Speaker 1: enough to essentially knock a population down in an area.
Speaker 1: But the problem is you got to keep doing that
Speaker 1: over and over and over again every year. So it's
Speaker 1: an expensive process that needs to be maintained. But it
Speaker 1: turns out it doesn't work well for anophlies mosquitos. So
Speaker 1: we talked about eighties mosquitoes. There's another genus of mosquitos
Speaker 1: called Anophlies that also tends to have a lot of
Speaker 1: species that transmit diseases to us, and that species it
Speaker 1: looks like it's a little bit harder at the early
Speaker 1: stages of their life to figure out which ones are
Speaker 1: males and which ones are females. And if you can't
Speaker 1: be sure, then maybe you're releasing a bunch of extra
Speaker 1: females into the environment who are like go and start
Speaker 1: biting people and possibly transmit diseases. So it works okay
Speaker 1: for eighties a jipdi if you're willing to release it
Speaker 1: over and over again over a large area, But it
Speaker 1: works less well for an off lease because there's this
Speaker 1: step where you need to figure out if there are
Speaker 1: boy mosquitos or girl mosquitos, and because that's hard to
Speaker 1: do in the lab, that makes this technique a little
Speaker 1: harder to use. So next, let's talk about bacteria. So
Speaker 1: I suspect to have Katrina's attention. So Wolbakia is a
Speaker 1: gram negative bacteria that's carried by a bunch of different
Speaker 1: kinds of insects. It lives inside of insects cells and
Speaker 1: it only passes down the female line, and so it's
Speaker 1: found ways to manipulate a lot of different insects species
Speaker 1: to help it transmit from one generation to another. So
Speaker 1: if a male who has the bacteria mates with the
Speaker 1: female who doesn't, the eggs that she produces won't hatch.
Speaker 1: But if the female has Wolbachia and the male doesn't,
Speaker 1: then she will lay as that all carry Woolbachia. And
Speaker 1: so essentially the bacteria has a way of sort of
Speaker 1: manipulating things so that eggs are produced in ways where
Speaker 1: the bacteria can transmit and in instances where the bacteria
Speaker 1: wouldn't be able to transmit. It just sort of like
Speaker 1: stops reproduction dead, so that there's a line there where
Speaker 1: nothing's happening. So in this way it can permeate the
Speaker 1: entire population.
Speaker 4: That's mind boggling. The sort of like genetic engineering by
Speaker 4: the bacteria to ensure that only lines that have the
Speaker 4: bacteria continue, that's incredible.
Speaker 13: It is incredible. Yeah, I remember when I first learned
Speaker 13: about this. It's kind of like blood types or something
Speaker 13: that there's like this incompatibility. But I know it's given
Speaker 13: people a real handle for engineering the populations. So I
Speaker 13: can only imagine what you're going to say next.
Speaker 1: So what I'm going to say next is that Scott
Speaker 1: O'Neill at Monash University noted that a different lab had
Speaker 1: found that viruses and fruit flies have trouble growing when
Speaker 1: they're infected by wolbachia.
Speaker 2: So this has nothing to do with REP production.
Speaker 1: This is just if wolbachia is there, it prevents the
Speaker 1: growth of viruses that otherwise would have killed the fruit flies.
Speaker 1: So O'Neil was like, well, what if we take wolbachia
Speaker 1: out of fruit flies and put it in mosquito eggs
Speaker 1: and then see if mosquitoes carrying this wolbachia are less
Speaker 1: likely to transmit dengae, which is another yeah, mosquito transmitted
Speaker 1: disease that can be lethal. And so essentially they did
Speaker 1: the incredibly difficult job of extracting a teeny tiny bacteria
Speaker 1: from a fruit fly sticking it into a teeny tiny
Speaker 1: little mosquito egg. Apparently they had to do this like
Speaker 1: thousands of times before it worked, but they eventually were
Speaker 1: able to get a strain of mosquitoes that were infected
Speaker 1: by the wolbachia that was found in these fruit flies.
Speaker 4: So you're telling me that they found a strain of
Speaker 4: Wolbachia that kills viruses, and since dangay is a virus,
Speaker 4: they were like, maybe this strain of Wolbachia is going
Speaker 4: to also kill dngay. That's crazy.
Speaker 2: It doesn't necessarily kill the virus.
Speaker 1: But it makes it so the virus can't reproduce, and
Speaker 1: if the virus can't reproduce, it can't go from mosquito
Speaker 1: to mosquito. And so they did some lab experiments and
Speaker 1: it was working well in the lab. And in fact,
Speaker 1: one of our listeners, Joe, sent us an email that
Speaker 1: included a link to an article where Wobakia infected mosquitoes
Speaker 1: had been released in Florida. So we're trying this like
Speaker 1: out in the wild.
Speaker 4: Wow.
Speaker 1: And so the question is does it work? And I
Speaker 1: looked for a really long time to try to find
Speaker 1: studies that had quantified this working, and I was able
Speaker 1: to find one study and it was in Indonesia and
Speaker 1: they released Wolbachia infected mosquitoes and it reduced the spread
Speaker 1: of dengay by seventy seven percent.
Speaker 4: Wow.
Speaker 1: So not one hundred percent, but like, man, those are
Speaker 1: much better odds. I'd take those odds. But then I
Speaker 1: found a twenty twenty four review paper that was trying
Speaker 1: to aggregate all of the Wobakia infected mosquito results, and
Speaker 1: they reported that essentially the only paper they were able
Speaker 1: to find was this paper from Indonesia. There were two
Speaker 1: other ongoing studies collecting data, but they hadn't published results yet.
Speaker 1: And so I would say at this point that this
Speaker 1: is super promising. I'd like to see evidence that it's
Speaker 1: working in some other areas before I could say like, ah, we.
Speaker 2: This is this might be the key.
Speaker 1: But for dengay, there's some preliminary evidence that this method
Speaker 1: is promising.
Speaker 4: Well, I'm a big fan of anything that's anti mosquito,
Speaker 4: and I'm a big fan of preventing dengay or other
Speaker 4: kinds of diseases, but the idea of like intentionally infecting
Speaker 4: mosquitoes with some kind of bacteria seems dangerous, like kind
Speaker 4: of I know this thing is going to like mutate
Speaker 4: and then all of a sudden it's some new horrible
Speaker 4: face melting disease or something.
Speaker 1: So you know, this bacteria is pretty widespread in nature,
Speaker 1: so it's not like we're introducing something super weird into
Speaker 1: the environment, but it is a different strain. I don't know,
Speaker 1: bacteria expert.
Speaker 15: What do you think, Katrina, Well, I guess I was
Speaker 15: just going to say that this Wolbakia bacteria, I think
Speaker 15: it's present in like forty percent of insects, and so
Speaker 15: of course there's going to be very individual relationships that
Speaker 15: each bacteria has with its own insect.
Speaker 13: But I don't know of the things that humans do
Speaker 13: to manipulate the environment, this seems like a relatively innocuous one.
Speaker 5: I think it's really cool.
Speaker 13: It's like not so toxic to just kind of scramble
Speaker 13: things around a little and hope for a better outcome.
Speaker 4: All right, Well, if people's faces get melted, it's on you.
Speaker 1: Oh no, well I think it's on Oxytech, which is
Speaker 1: a company that is releasing some of these mosquitoes. I
Speaker 1: don't know that we can blame Katrina, she didn't release them.
Speaker 16: But thank you for looking up for me. Kelly, Yeah,
Speaker 16: you're welcome. I like when we can team up against
Speaker 16: Daniel so well.
Speaker 4: You know, then maybe I need you to chime in
Speaker 4: on a topic that's been discussed heatedly at the Whites
Speaker 4: and Institute board meetings recently, really, which is you know
Speaker 4: what is the source of all the mosquitoes at the
Speaker 4: Whites and is too compound that are biting Daniel. And
Speaker 4: for example, I'm against having sources of fresh water near
Speaker 4: the house, but Katrina is growing vegetables hydroponically in our backyard.
Speaker 4: H what do you think, Kelly, I need a ruling.
Speaker 13: There's no way for a mosquito to get into this
Speaker 13: hydroponic growth chamber or for a mosquito to get out,
Speaker 13: so I just really don't think it's possible for them
Speaker 13: to be in there. But there is sometimes like a
Speaker 13: bowl of water that collects from rain that I don't notice,
Speaker 13: and I'm sorry if that caused any mosquito growing to happen.
Speaker 4: I mean, I'm hearing all of your fancy engineering explanations
Speaker 4: for why this can't happen, but I'm taking measurements of
Speaker 4: mosquito bites and I'm telling you it's high.
Speaker 13: It feels like there's been a lot of mosquitoes lately.
Speaker 13: But I thought we could blame that shipping container of
Speaker 13: the Port of Long Beach. Isn't that why?
Speaker 4: Well, what do you think, Kelly?
Speaker 1: I think that I like every opportunity that I can
Speaker 1: have to side with Katrina, But I don't really want
Speaker 1: to get in the middle of a marital spat, so
Speaker 1: I'm going to run away and call a commercial break
Speaker 1: and pretend none of this happened.
Speaker 2: When we get back, and we're back and we are talking.
Speaker 1: About genetic engineering techniques for controlling mosquito populations. This time around,
Speaker 1: we're about to get to gene drives, which was the
Speaker 1: listener's question. This is the most roundabout way of getting there.
Speaker 1: But first let's talk about some genetic engineering where essentially
Speaker 1: you take males and you make it so that if
Speaker 1: they don't encounter tetracycline, they will die.
Speaker 4: What is tetracycline.
Speaker 1: Tetracycline is an antibiotic, and essentially you make it so
Speaker 1: that the males are making a protein that when it's
Speaker 1: made it messes up the cells activity. But in the
Speaker 1: presence of tetracycline, that protein is suppressed so it doesn't
Speaker 1: get made. So males in the lab are given tetracycline,
Speaker 1: they act normal, but when they produce suns in the wild,
Speaker 1: the suns start producing this protein like crazy. It messes
Speaker 1: up their cell activity and they die. And so the
Speaker 1: females do lay eggs but their eggs don't tend to survive.
Speaker 4: So you genetically engineer mosquitos to be dependent on this
Speaker 4: thing that you can give them. So when they go
Speaker 4: out there in the wild, their bodies are making this
Speaker 4: protein and since they don't have this magic powder, they
Speaker 4: end up killing themselves.
Speaker 2: They end up dying. Yeah.
Speaker 4: Wow.
Speaker 1: These are pretty complicated strategies, and they also are strategies
Speaker 1: that tend to make a lot of people uncomfortable. So,
Speaker 1: for example, this has been tried in the Cayman Islands, Panama, Brazil,
Speaker 1: and Florida, and in the Florida Keys, for example, the
Speaker 1: initial response was like massive backlash against the release of
Speaker 1: these GMO mosquitoes. They ended up getting released anyway, but
Speaker 1: there were people who were saying like, I'm gonna find
Speaker 1: the boxes where there's these mosquitos are supposed to hatch from,
Speaker 1: and I'm gonna dump them out or pour bleach in them.
Speaker 1: And I think in general it's really important that you
Speaker 1: have public buy in for these sorts of things, because
Speaker 1: otherwise you just get you know, you get people who
Speaker 1: are justifiably upset. They don't understand what's being released. They're
Speaker 1: worried that the genes that got put in the mosquitoes
Speaker 1: might jump into them.
Speaker 4: Is that what the concern is that the that they're
Speaker 4: going to end up depending on tetracyclin also or is
Speaker 4: it just a generic like I'm scared of GMO stuff.
Speaker 1: I think it's more of a generic. I'm scared of
Speaker 1: GMO stuff. You know, folks don't want GMO foods. I
Speaker 1: think they don't necessarily like the idea of getting bitten
Speaker 1: by GMO mosquitos.
Speaker 13: I think they also don't like the idea of putting
Speaker 13: an engineered gene out in the environment and not knowing
Speaker 13: where it's going to end. So like these island capture experiments,
Speaker 13: where of course the idea is that it's an island
Speaker 13: so it's somewhat contained, are still unsettling because the world
Speaker 13: is so connected right now, so it's hard to know
Speaker 13: what the reach of an experiment like that.
Speaker 2: Will be exactly.
Speaker 1: And so while these releases do first have to go
Speaker 1: through like a complicated series of approvals through groups like
Speaker 1: the Food and Drug Administration, the United States Department of Agriculture,
Speaker 1: the Environmental Protection Agency, it is still the first time
Speaker 1: we're doing something like this, and so ox Tech did
Speaker 1: release mosquitos that had this tetracycling thing happening, and some
Speaker 1: of the genes from the mosquitoes did end up being
Speaker 1: found in wild mosquito, so like those genes had escaped
Speaker 1: into the population. There were some headlines at the time
Speaker 1: that sort of were way overblown. They said things like,
Speaker 1: these genes are going to make the wild mosquitoes even
Speaker 1: better at biting us, and now we've just made our
Speaker 1: problem worse. There wasn't necessarily any evidence for that, but
Speaker 1: there was evidence that genes that were essentially manufactured in
Speaker 1: a lab are now part of the wild population and
Speaker 1: might be there forever. And we don't really understand if
Speaker 1: that is going to do anything at all.
Speaker 4: I understand the concern that these genes that you've put
Speaker 4: into one mosquito might end up in a wild mosquito,
Speaker 4: and you don't know exactly what's going to happen. Maybe
Speaker 4: it turns them into incredible hulk mosquitos, whatever. But how
Speaker 4: does a gene go from that mosquito to the wild mosquitos.
Speaker 4: Does it have to breed with those mosquitoes or is
Speaker 4: there some other weird horizontal thing happening.
Speaker 1: So I think what happened in this case is that
Speaker 1: one of the mosquito babies that was supposed to die
Speaker 1: did not, and so it survived, had some of the
Speaker 1: genes that it got from its genetically engineered dad, and
Speaker 1: then is passing that through the generation.
Speaker 4: Okay, so it's through breeding.
Speaker 13: Yeah, you could imagine some compensation that allowed it to
Speaker 13: survive with that toxic protein, and then the toxic protein
Speaker 13: would stick in the population. I mean, I guess in
Speaker 13: my mind, there's so much evolution and transfer of genetic
Speaker 13: material all the time that any tiny little drop that
Speaker 13: comes from a lab feels insignificant to me. But I
Speaker 13: do understand why it feels unsettling.
Speaker 1: That's my gut feeling. Also, like horizontal gene transfer happens
Speaker 1: between insects and our food, and just all sorts of
Speaker 1: different transfers are happening all the time in nature. I'm
Speaker 1: less worried about a genetic sequence that seems pretty benign
Speaker 1: getting out into the wild. But on the other hand,
Speaker 1: I'm somebody who is totally fine eating genetically modified foods.
Speaker 1: But I understand that that's not true for everybody, and
Speaker 1: so I can understand why this would be upsetting to
Speaker 1: some people.
Speaker 4: I think generally, you know, biologists don't know how everything works,
Speaker 4: and we're pushing buttons and pulling levers on a big,
Speaker 4: complicated machine, and it does feel like one little button
Speaker 4: on a huge machine. But you know, you release the
Speaker 4: right pathogen and it can definitely have a big impact
Speaker 4: on a population.
Speaker 2: Yeah, I think it's important to be humble.
Speaker 1: Yeah, So let's get to gene drives, which is probably
Speaker 1: the most like ethically controversial thing that we'll be talking
Speaker 1: about today. And you know, we bring Katrina on the
Speaker 1: show because we generally love Katrina's input, but she also
Speaker 1: understands gene drives. And I spent a day smashing my
Speaker 1: head against a paper I could not understand. And so Katrina,
Speaker 1: could you explain gene drives for us, please?
Speaker 13: So, a gene drive refers to when you use genetic
Speaker 13: engineering to force a gene through a population at a
Speaker 13: really high rate. So normally our genes are inherited approximately
Speaker 13: fifty to fifty, so the chances of inheriting a pertinent
Speaker 13: trait are not weighted in one direction or another. What
Speaker 13: a gene drive does is it ensures or drives that
Speaker 13: a particular trait will be more frequent in the population
Speaker 13: and so, and we've actually been using this technique in
Speaker 13: the context of mosquitos with a few different strategies in mind.
Speaker 13: This it could be something that affects fertility, so then
Speaker 13: you drive the population to extinction, So that would lead
Speaker 13: to you know, fewer mosquitos is the goal there. But
Speaker 13: then there's also strategies where you try to prevent the
Speaker 13: mosquitoes from spreading malaria. So there's some mosquitos that are
Speaker 13: naturally resistant to carrying the malaria parasite, and so spreading
Speaker 13: that strategy is another gene drive technique.
Speaker 4: So can we dig a bit deeper, Like I understand
Speaker 4: sort of the basics of genetics at the sort of
Speaker 4: pea pod level, you know from Gregor Mendel, and you
Speaker 4: have a fifty percent chance of getting the gene from
Speaker 4: one parent or from the other. How does the gene
Speaker 4: drive affect which genes you're going to end up with?
Speaker 13: Well, okay, the one really cool strategy that people use
Speaker 13: to make gene drives work is to borrow the phage
Speaker 13: defense system called Crisper cast nine. As you guys hopefully
Speaker 13: know all about, there are these viruses called phages that
Speaker 13: can infect bacteria and the bacteria defund themselves in all
Speaker 13: kinds of interesting ways, and one of them has been
Speaker 13: co opted for all kinds of genetic engineering. It's called
Speaker 13: Crisper cast nine, and it turns out whenever the phage
Speaker 13: infect the bacteria, the bacteria keep a little record of
Speaker 13: little snippets of the genes that the phage was trying
Speaker 13: to infect the bacteria with. And then they put a
Speaker 13: little pair of scissors, a gene that can chop DNA
Speaker 13: up next to the little memory bank of all the
Speaker 13: little phage genes that were left behind. And then when
Speaker 13: the phage tries to infect the scissors, the gene that
Speaker 13: has the DNA cutting enzyme on it will match up
Speaker 13: with the pieces of the phage gene and it'll chop
Speaker 13: up the phage as it tries to enter. The Nobel
Speaker 13: Prize last year to Jennifer Dawna and Manuel Sharpentier because
Speaker 13: they had the idea of taking this tool and using
Speaker 13: it to engineer genes in any system.
Speaker 4: So, just to back up and make sure we're understanding,
Speaker 4: the Crisper idea is some sort of like bacterial immune
Speaker 4: system where it remembers the viruses it's seen before and
Speaker 4: has a bunch of guys floating around which will recognize
Speaker 4: those viruses. Plus it comes with scissors so that when
Speaker 4: the viruses come near, it latches on and then it
Speaker 4: chops them up and then the viruses can't infect the
Speaker 4: bacteria anymore. So the basics of how the Crisper system works, yeah.
Speaker 5: That is exactly the basics.
Speaker 13: But the idea of using it as a tool is
Speaker 13: really cool because basically, now you have a system that
Speaker 13: can go and find a particular DNA sequence and then
Speaker 13: it's got scissors right next to it, so it can
Speaker 13: go cleanly chop things out exactly next to whatever sequence is.
Speaker 5: Next to it.
Speaker 13: So with the phases, the bacteria using it to chop
Speaker 13: up phages. But now imagine you wanted to go in
Speaker 13: there and slice and dice a mutation that was causing
Speaker 13: sickle cell anemia.
Speaker 5: You can do that.
Speaker 13: That actually is happening in people right now, which is amazing.
Speaker 13: So people with sickle selenemia now can have some access
Speaker 13: to Crisper CAST nine genetic engineering technology where you use
Speaker 13: the same scissors, but this time you match it to
Speaker 13: the gene causing the sickle cell disease and you have
Speaker 13: the scissors go in there and snip out the problematic
Speaker 13: gene and replace it with a healthy gene. And I mean,
Speaker 13: that's to me amazing that that is actually working in people.
Speaker 13: The idea is not that old. I mean the discovery
Speaker 13: is somewhat recent. And so that's the same strategy that's
Speaker 13: been used to build mosquito gene drives.
Speaker 4: So I understand how Crisper can let you edit your genes,
Speaker 4: which on one hand sounds like why is that are
Speaker 4: you know, you just like go in and edit the data.
Speaker 4: But like this data stored on DNA, you can't just
Speaker 4: go in there and like manipulate it with tweezers. You
Speaker 4: need some of like microscopic manipulation tools, and that's what
Speaker 4: Crisper is giving you. But how does that connect to
Speaker 4: gene drives. How does Crisper let you enhance which genes
Speaker 4: get passed down in the population.
Speaker 13: Well, you engineer mosquitos that contain a Crisper cast nine
Speaker 13: gene set in there. And so you could put the
Speaker 13: scissors right next to a gene that's important for fertility,
Speaker 13: or you could put the scissors right next to a
Speaker 13: gene that controls whether the mosquito is able to be
Speaker 13: infected by the malaria parasite, and so if you put
Speaker 13: that in there, then the crisper cast nine scissors will
Speaker 13: go around spreading that gene even after the mosquito is born,
Speaker 13: so it's throughout the mosquito's life the gene drive will
Speaker 13: be active and it will continue to spread that gene.
Speaker 13: So your opportunity for picking up your genetic traits will
Speaker 13: not end right at the moment of Mendelian inheritance.
Speaker 5: The gene drive will can continued to be active after.
Speaker 4: Oh, in the same way that you go in and
Speaker 4: edit somebody's genes when they're alive to remove the bit
Speaker 4: that's giving them some condition, you're basically giving these mosquitoes
Speaker 4: a little bit of genetic engineering during their whole lifetime,
Speaker 4: so it's not just what they inherit. You're like changing
Speaker 4: them after the fact. That's cool.
Speaker 13: Yeah, So basically, if that gene drive is in there,
Speaker 13: every time the little cassette that has the scissors on
Speaker 13: it encounters the gene that it can match to, it
Speaker 13: will swap things around, so you can. Like one of
Speaker 13: the examples that I really loved that I read about
Speaker 13: was where they had a naturally malaria or resistant mosquito,
Speaker 13: and it was just caused by one snip and a gene,
Speaker 13: a single mutation, and they made a gene drive that
Speaker 13: forced that mutation through the population. But it's it's a
Speaker 13: naturally existing gene, so they're not making a Frankenstein mosquito here,
Speaker 13: and it made it so that the malaria infectivity rate
Speaker 13: of the mosquito population could go down.
Speaker 1: I found another paper where they were tinkering with the
Speaker 1: gene that they called double sex, and essentially what happened
Speaker 1: is they made sure, you know that everybody got two
Speaker 1: versions of double sex, and if you're a female that
Speaker 1: has the double sex genes, you are sterile and you
Speaker 1: also look a little bit male like. But males who
Speaker 1: get it are normal and they can go on spreading
Speaker 1: the gene drive. So essentially every baby that's produced that's
Speaker 1: a female is not going to make any more babies,
Speaker 1: and males that are produced are going to be able
Speaker 1: to go on in mate, but they're going to pass
Speaker 1: this gene drive onto their offspring, and so they'll create
Speaker 1: female babies that die and male babies that go off
Speaker 1: and continue to pass the gene drive until it gets
Speaker 1: through essentially the entire population. I think is the goal. Wow,
Speaker 1: well yeah, and so this has not yet been released
Speaker 1: into the environment, and so, as Katrina noted, there's two
Speaker 1: different methods. You could try to either kill the mosquitoes directly,
Speaker 1: or you could do something to the mosquito so they
Speaker 1: can't transmit the dizzy anymore. There might be some other
Speaker 1: options too, but those are the two things that people
Speaker 1: are working on right now. But this, I think this
Speaker 1: technique in particular, is a little scarier ecologically because you know, like,
Speaker 1: what if that gene drive jumps to I don't know,
Speaker 1: another mosquito species. Maybe having two mosquito species eradicated doesn't
Speaker 1: sound so bad, but what if somehow that gene drive
Speaker 1: is able to jump to I don't know, a ladybug
Speaker 1: that helps control pests in agriculture or something. And now
Speaker 1: we've got this thing that could lead to extinction, and
Speaker 1: there's some concern that if you release it, you know,
Speaker 1: where is it going to end up?
Speaker 4: But how do these jumps happen? Earlier we were saying
Speaker 4: that the genetic engineering that you manufacturing your mosquitos can
Speaker 4: spread to wild mosquitoes through inheritance, But we're not having
Speaker 4: mosquitoes like having babies with ladybugs. How does that jump possible?
Speaker 1: So, as we're going to talk about in a future episode,
Speaker 1: the definition of a species isn't always entirely crisp. Sometimes
Speaker 1: you can get you know, individuals that are in the
Speaker 1: same genus, for example, mating with each I don't know
Speaker 1: if they get confused or they have very particular interests
Speaker 1: something they're looking for in a partner.
Speaker 2: No judge, but no judgment, no judgment.
Speaker 1: But if you know the mosquito species, you put the
Speaker 1: gene drive in mates with another mosquito species. Now you're
Speaker 1: wiping out that species too.
Speaker 2: And you can.
Speaker 1: Imagine yourself jumping around the tree of life and whenever
Speaker 1: you get some you know, cross species mating, you've now
Speaker 1: got that species wiped out too.
Speaker 4: So crisper can move because species aren't crisp, is what
Speaker 4: you're telling me.
Speaker 5: Ah, that's right, I mean, yeah, that's definitely.
Speaker 13: One way is through mating partners that might be a
Speaker 13: little bit less related. But I mean another big strategy
Speaker 13: is sometimes there are big leaps in genes that get
Speaker 13: transferred across the tree of life, and that often is
Speaker 13: facilitated by viruses. So, for example, eight percent of the
Speaker 13: human genome is in the form of endogenous retroviruses. So
Speaker 13: that means that one of our long ago ancestors had
Speaker 13: a virus infect one of their germline cells, one of
Speaker 13: their sex cells, and we have inherited that to the
Speaker 13: tune of literally eight percent of our genome. Most of
Speaker 13: them are pretty dormant and haven't really affected us that much,
Speaker 13: but some of them have led to the biggest innovations
Speaker 13: in biology. So like, for example, did you guys know
Speaker 13: that the gene that led to the placenta evolving came
Speaker 13: from a virus? So an endogenous retrovirus that infected one
Speaker 13: of our ancestors back before mammals existed, had a gene
Speaker 13: in it that helps with membrane fusion. So like that
Speaker 13: gene in a virus is great for helping the cell
Speaker 13: membrane fusee but in a mammal it allows for the
Speaker 13: fusion between the uterus and the placenta cool, so those
Speaker 13: kind of jumps can happen. And to me, that's a
Speaker 13: really big question about gene drives because what if this
Speaker 13: crisper gene gets transmitted farther afield. I think that's the
Speaker 13: real concern, But keep in mind, in your own gut.
Speaker 13: Right now, you have thousands of bacteria that contain all
Speaker 13: kinds of crisper systems, and I'm not worried about those
Speaker 13: transmitting into human cells.
Speaker 1: And I should note there are labs that are working
Speaker 1: on anti gene drive techniques, like a gene that you
Speaker 1: could release into the population that would sort of stop
Speaker 1: the gene drive. And so there are some folks who
Speaker 1: are forward thinking about this problem and are trying to
Speaker 1: stop it. But then we can return to Daniel's earlier point,
Speaker 1: which is that biology is complicated and biologists don't necessarily
Speaker 1: know what's going to happen. So, like, what if we
Speaker 1: knock out one mosquito species, a different mosquito species fills
Speaker 1: that niche, and that species is even better at transmitting
Speaker 1: the disease. Now we've you know, maybe we can release
Speaker 1: gene drives again to control the problem. But like, it's
Speaker 1: hard to know what's going to happen to a system
Speaker 1: when you remove an animal that has you know, a
Speaker 1: large number of individuals out in the population, and we
Speaker 1: don't really understand the ecological impacts. So Daniel mentioned that
Speaker 1: some mosquitoes pollinate chocolate, you know, may what if you
Speaker 1: have a mosquite species that ends up being an important
Speaker 1: food source, for example, for a fish species that is
Speaker 1: an important source of protein for the local community. So like,
Speaker 1: there's a lot of you know, ecological stuff that might
Speaker 1: happen that we don't understand very well. And so making
Speaker 1: the decision to knock out a species because we've decided
Speaker 1: we wanted to do that, you know, could have some
Speaker 1: other implications. But if, on the other hand, you're talking
Speaker 1: about you know, more than half a million people dying
Speaker 1: every year from malaria, my tolerance for taking risks goes
Speaker 1: up a little bit. But those risks should be well
Speaker 1: thought through, in my opinion, and I hope that.
Speaker 4: You're including my itchy ankles from mosquito bytes in your calculation.
Speaker 4: I'm not away a lot.
Speaker 2: I'm not no.
Speaker 4: And of course Kitchen is going to vote. We do
Speaker 4: so on that voted again.
Speaker 1: So where we are on this right now is that
Speaker 1: some genetically modified mosquitoes have been released and we're doing
Speaker 1: tests on those, but no gene drive mosquitoes have been
Speaker 1: released yet. There was a target malaria was working in
Speaker 1: Bikina Fassa to try to get community buy in, to
Speaker 1: get people on board with this idea of releasing gene drives,
Speaker 1: but recently their facility was essentially rated and they were
Speaker 1: told that their project is being shut down. It was
Speaker 1: a little bit unclear what happened because it seemed like
Speaker 1: the Target Malaria group was in good with the local community,
Speaker 1: in good with the government. There have been some like
Speaker 1: think tanks that think that the problem actually is Russian disinformation,
Speaker 1: where this message has been spread that we are using
Speaker 1: genetic modification to make people sterile, and you know, releasing
Speaker 1: these genetic mosquitos will sterilize the local population. So it
Speaker 1: has become a complicated ethical, geopolitical problem, and that's where
Speaker 1: we are right now. We are sort of trying to
Speaker 1: decide as a society what we're going to do when
Speaker 1: we have this technique that could be used to save
Speaker 1: a bunch of lives from malaria, but has you know,
Speaker 1: potential implications, some of which we know about and some
Speaker 1: of which we might not even understand unless we were
Speaker 1: to actually try the experiment.
Speaker 2: So it's complicated because it's biology, but.
Speaker 4: It's worthwhile because these are people's lives. It matters.
Speaker 13: Yeah, I think it's so interesting that it's more controversial
Speaker 13: when we understand what we're doing better. I mean, for example,
Speaker 13: in agriculture, we've been selecting for traits for thousands of
Speaker 13: years that have all kinds of ecological impact, and we
Speaker 13: don't find that to be controversial. But as soon as
Speaker 13: we use molecular biology tools to genetically engineer things, it's
Speaker 13: less understandable and somehow scarier, although the implications could be
Speaker 13: the same.
Speaker 5: So I think that's really interesting.
Speaker 1: All right, So we have had a fun, complicated discussion
Speaker 1: about mosquitos and genetic engineering, and Katrina, I have no
Speaker 1: doubt we'll bring you back on the show five or
Speaker 1: six more times before.
Speaker 2: The end of the year, which is only a couple
Speaker 2: weeks off. Thanks for coming back on the show.
Speaker 5: Well, thank you for having me.
Speaker 1: Thank you to our listeners for submitting their questions. Let's
Speaker 1: hear what they had to say about the episode.
Speaker 14: I really appreciate you getting to my question and in
Speaker 14: the most relevant episode. I can't say that I'm entirely
Speaker 14: convinced that the reason gene drives haven't been tested yet
Speaker 14: aren't nefarious. After all, if your goal was eradication and
Speaker 14: you released enough mosquitoes on a small island, and considering
Speaker 14: the length of the mosquito life cycle, how long would
Speaker 14: it take to eradicate the species entirely a short time
Speaker 14: period leaves very little time for the genes to jump.
Speaker 14: If the gene drive did jump species and eradicate another
Speaker 14: species of mosquito, oh why has no native mosquitos to
Speaker 14: worry about? In fact, the six to eight invasive mosquito
Speaker 14: species on the islands would make a great test case
Speaker 14: to see if the.
Speaker 4: Gene drives do jump species.
Speaker 14: Maybe some diligent pesticide use by the ports could keep
Speaker 14: any modified mosquitos from leaving the island before total eradication. Overall,
Speaker 14: it seems much less risky than Uruguay's plan to use
Speaker 14: gene drives to eradicate screw worms. Given the biodiversity of
Speaker 14: South America. Maybe the answer is in Wolbakia, which you covered.
Speaker 14: Perhaps is just less risky. It looks like they started
Speaker 14: attempting to use it to radicate coolx mosquitos on Maui
Speaker 14: to save native birds. Thanks so much.
Speaker 1: Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio.
Speaker 2: We would love to hear from you, We really would.
Speaker 4: We want to know what questions you have about this
Speaker 4: Extraordinary Universe.
Speaker 1: We want to know your thoughts on recent shows, suggestions
Speaker 1: for future shows.
Speaker 2: If you contact us, we will get back to you.
Speaker 4: We really mean it. We answer every message. Email us
Speaker 4: at Questions at Danielankelly.
Speaker 1: Dot org, or you can find us on social media.
Speaker 1: We have accounts on x, Instagram, Blue Sky and on
Speaker 1: all of those platforms.
Speaker 2: You can find us at D and K Universe.
Speaker 4: Don't be shy, write to us