Speaker 1: Brought to you by Toyota. Let's go places. Welcome to
Speaker 1: Forward Thinking. Hello, and welcome to Forward Thinking, this podcast
Speaker 1: that looks at the future and says, rescue me from
Speaker 1: me and all that I believe. I'm Lauren Volgabon and
Speaker 1: I'm Joe McCormick, and our regular host Jonathan Strickland is
Speaker 1: not with us today. He is still out on vacation.
Speaker 1: He's having lovely adventures in his absence. We went on
Speaker 1: a very short Billy Corgan impersonation to kick there, but
Speaker 1: that's no, was not recording that. I kind of hope
Speaker 1: he was. It was really delightful. Both of you do
Speaker 1: a really good smashing pumpkins. Anyway. Yeah, so today we're
Speaker 1: gonna be talking about a fascinating topic in genetics. Yes,
Speaker 1: but we want to get there in a kind of
Speaker 1: roundabout way by talking about islands. Yeah. We want to
Speaker 1: get there via the Galapagos. Have you ever been to
Speaker 1: the Galapagos? I have not, have you No, I haven't,
Speaker 1: But I want to go there someday. I know. It's lovely,
Speaker 1: it's it's a I mean, there's so many things there
Speaker 1: that you literally cannot find anywhere else, and not like
Speaker 1: restaurants like like beautiful wildlife. Yeah, I know, the restaurants
Speaker 1: seen there is probably not not what people go for.
Speaker 1: I don't think it is now. Yeah, so you're probably familiar,
Speaker 1: but just in case you're not. The Galapagos or a
Speaker 1: group of islands, or more accurately, a volcanic archipelago in
Speaker 1: the Pacific Ocean about about a thousand kilometers off the
Speaker 1: west coast of Ecuador, right along the equator. I think
Speaker 1: it actually straddles the equator. Yeah, yeah, and the Galapagos
Speaker 1: appear to have been mostly uninhabited before the Spanish visited
Speaker 1: in the sixteenth century by humans that is. Yeah. The
Speaker 1: glaucost Islands are situated more or less smack in the
Speaker 1: middle of these three conjoining tectonic plates and thus three
Speaker 1: different ocean currents, meaning that over the millennia, lots of
Speaker 1: credits from all over the world have wound up there,
Speaker 1: and the ones that stayed and reproduced branched off from
Speaker 1: their ancestors due to the unique living conditions and uh
Speaker 1: and separation from the general population. Yeah, and for this
Speaker 1: reason today the Galapagos I think are mainly known for
Speaker 1: their wildlife. That that's why people mostly want to go
Speaker 1: to this place. Yeah, so you've got, for example, the
Speaker 1: endemic Galapagos penguin, the Galapagos giant tortoise, and there are
Speaker 1: a few subspecies of that, like the saddleback tortoise and
Speaker 1: the dome tortoise, and then of course those smug, insufferable
Speaker 1: marine iguanas. Did did a marine iguana from Galapacos? Like? Wrong?
Speaker 1: You in your past? You know, I would never advise
Speaker 1: anybody treat them with anything but the utmost respect for nature.
Speaker 1: But just look at their faces. They just look like jerks.
Speaker 1: They do you sitting on those rocks, so they look
Speaker 1: really proud and slappable. Yeah, there's something about them. No,
Speaker 1: do not slap an iguana. Never slap an iguana. Why
Speaker 1: would you do that? The Galapagos. So yeah, so they've
Speaker 1: got they've got all these animals that are very beautiful
Speaker 1: and unique and and iconic in many ways. For one reason,
Speaker 1: I think because the Galapagos were, uh, this archipelago is
Speaker 1: one of the places that Charles Darwin stopped on his
Speaker 1: voyage on the h MS vegal famously. Yes, yeah, and
Speaker 1: so I think for that reason, they've become sort of
Speaker 1: emblematic of animal evolution and ecology in many ways since then.
Speaker 1: And like I said, I've never been, but I've always
Speaker 1: heard that because of the lack of large natural predators
Speaker 1: on the island, many of its animals are just very
Speaker 1: friendly chill. Yeah, they're they're fine basically with humans hanging
Speaker 1: out around them. Yeah, and they'll allow you to approach
Speaker 1: them without running away. So so that can be very
Speaker 1: wonderful if you are a peaceful, conservation minded ecological tourists
Speaker 1: who wants to visit the island and see some animals.
Speaker 1: Not so great for the animals if you are, say
Speaker 1: a pirate or a whaler or something that wants to
Speaker 1: kill a tortoise and eat it for its meat which
Speaker 1: has figured into the island's history, or or save it
Speaker 1: for or harvested for its beautiful shell or et cetera. Sure, exactly.
Speaker 1: So these days the glopacos are there's sort of a
Speaker 1: popular wildlife and conservation tourist destination, but the archipela goes.
Speaker 1: Beautiful and fascinating endemic species aren't the only critters on
Speaker 1: this island group today. Yeah, because if you know anything
Speaker 1: about sea travel, especially sea travel in prior centuries, humans
Speaker 1: weren't the only things on these ships. Right. There is
Speaker 1: a rodent problem, or has been a rodent problem in
Speaker 1: the Galapagos, And so according to the Galapagos Conservancy, the
Speaker 1: brown rat Rattus norvegicus and the black rat Ratus ratus.
Speaker 1: They were introduced to the Glapacos probably in the seventeenth
Speaker 1: or eighteen centuries by seafaring visitors like whalers and privateers.
Speaker 1: And as you alluded to, this is not an unusual story.
Speaker 1: Wherever humans go, various rodents tag along with us. There's
Speaker 1: sort of like a you know when you see a
Speaker 1: shark swimming swimming and it's got those little things hanging
Speaker 1: onto the body on side of it, and they just
Speaker 1: go along with it. Yeah, yeah, Or the barnacles that
Speaker 1: live on whales that whales sometimes use as big battering
Speaker 1: rams and whale battles. Yeah. So if we're the shark,
Speaker 1: those things are rodents, they just come along with us. Yeah,
Speaker 1: they're just hanging out. Because humans create a lot of trash.
Speaker 1: I think that actually is one of the reasons. But
Speaker 1: so like many other cases where organisms are introduced by
Speaker 1: humans to new ecosystems that haven't evolved to accommodate them,
Speaker 1: they haven't always been there. The native organisms can really suffer,
Speaker 1: and this has been the case over over the centuries
Speaker 1: with introduced rats and mice in the Galapagos. Many native organisms,
Speaker 1: especially birds and reptiles, have been severely threatened by these rodents,
Speaker 1: which tend to prey on their eggs and they're young.
Speaker 1: We've talked a bunch of times before in the show
Speaker 1: about these invasive species and then the kind of damage
Speaker 1: that they can do, because yeah, they nothing involved on
Speaker 1: that island to protect itself from this sort of threat exactly.
Speaker 1: So the Galapagos giant tortoise is one example. So the
Speaker 1: giant tortoise has been severely threatened on multiple islands by
Speaker 1: introduced animals, including rats, for one thing, though historically we
Speaker 1: would be remiss if we didn't also mention, as I
Speaker 1: alluded to a minute ago, the role humans played in
Speaker 1: more directly reducing those tortoise populations themselves through for example, hunting.
Speaker 1: And I don't know whether you'd say this is a
Speaker 1: direct or indirect. I guess indirect through habitat destruction. So
Speaker 1: the tortoises eggs and their hatchlings have been preyed upon
Speaker 1: by animals like rats, especially rats, so badly that on
Speaker 1: the island of pin Zone. Scientists believe that until just
Speaker 1: a couple of years ago, there had been no new
Speaker 1: tortoise hatchlings in about a hundred and fifty years. Yeah, exactly.
Speaker 1: So conservationists did come up with plans for ways to
Speaker 1: get around that, and that some of their plans actually
Speaker 1: did succeed. For example, uh decades old conservation efforts focused
Speaker 1: on breeding tortoises in captivity and keeping them there until
Speaker 1: the young tortoises were about four or five years old,
Speaker 1: at which point they became too large for the rats
Speaker 1: to prey on them. Referred to in the literature as
Speaker 1: being quote rat proof, rat proof tortoises, thank you, scientists.
Speaker 1: You'd think the shell would make them always rat proof,
Speaker 1: but I guess rats are crafty. I guess. Yeah. Well,
Speaker 1: and and when the tiny little baby baby tortoises are
Speaker 1: are you know, too small or I don't know, as
Speaker 1: I don't want to imagine this. It's very sad, but
Speaker 1: but yeah, so that did help. But even with this
Speaker 1: measure in place, the tortoise eggs would be threatened in
Speaker 1: the wild. So the problem was bad enough that conservationists
Speaker 1: trying to save the tortoises, began a program to eradicate
Speaker 1: the invasive rats in through mass poisoning with rat bait
Speaker 1: essentially okay poison, but so far it does seem to
Speaker 1: have worked. In January there was a letter to Nature
Speaker 1: where a group of scientists and conservationists confirmed that in
Speaker 1: December of the previous year, so December twenty fifteen, ten
Speaker 1: saddleback giant tortoise hatchlings had been found on pin Zone Island,
Speaker 1: and they believed that if they saw these, there must
Speaker 1: be more than they haven't found. And this was the
Speaker 1: first time hatchlings, as we said, have been observed in
Speaker 1: the wild and more than a d and fifty years,
Speaker 1: and so it suggests that the animals are finally able
Speaker 1: able to recover their population through natural breeding, not breeding
Speaker 1: in captivity. Yeah. Oh, that's that's wonderful. I have less
Speaker 1: good news to report, Yeah, yeah, just over the past
Speaker 1: month or so. Sadly, in May to June of six,
Speaker 1: news broke of of the first confirmed extinction of a
Speaker 1: bird species on Galapagos and the bird in question, which
Speaker 1: is the sun cuistal ball vermilion flycatcher. I'm not going
Speaker 1: to try the Latin because I didn't practice it before
Speaker 1: the show. Um they no, no birds of this type
Speaker 1: had been seen in the wild since seven so they
Speaker 1: were presumed to be extinct already. But but this this
Speaker 1: news comes after a genealogical and morphological review marked the
Speaker 1: bird as being its own species instead of just a
Speaker 1: subspecies as it was previously assumed to be. And what
Speaker 1: caused this extinction rats, I mean rats mostly um eating
Speaker 1: eating the eggs and also a parasitic fly that kills
Speaker 1: chicks when they do manage to grow to hatch. So
Speaker 1: bad times for this vermilion flycatcher. And they're really pretty,
Speaker 1: is the sad thing. They're just really a little scarlet
Speaker 1: colored birds anyway, sad though even we should always remember
Speaker 1: that even the ugly creatures should have deserved a good shake. Yeah. Absolutely,
Speaker 1: And now there are lots of other vermilion flycatchers of
Speaker 1: a various species and subspecies on the island, but lots
Speaker 1: of them are also in decline. And there's really interesting
Speaker 1: work being done in studying the birds individual island based
Speaker 1: adaptations because different islands within the archipelago have have have
Speaker 1: different environments and so you can really get into the
Speaker 1: genetics of how they adapted and broke off from each
Speaker 1: other within those populations. But it's a situation where researchers
Speaker 1: are basically scrambling to study the birds before they all disappear.
Speaker 1: They're they're hoping that a few more species can be
Speaker 1: and subspecies can be distinctified and identified, but they might
Speaker 1: not if we can't start controlling this rat population. Yeah,
Speaker 1: And so this is sort of a model of an
Speaker 1: issue that goes on around the world where small island
Speaker 1: populations of endemic animals are threatened by invasive species that
Speaker 1: humans bring along with them when they travel to these islands. So,
Speaker 1: in many cases, island wildlife conservation that's have been able
Speaker 1: to make some progress saving endemic species by eradicating invasive
Speaker 1: populations through totally conventional means poisoning, traps, etcetera. But none
Speaker 1: of those methods are ideal. When you lay out, you know,
Speaker 1: thousands of pounds of rat poison, you can just guess
Speaker 1: that that's not the thing you want to do most
Speaker 1: to the actually college, Yeah, or even traps, traps that
Speaker 1: other animals could blunder on into sure. And also these
Speaker 1: methods are just difficult to use, Like they can be
Speaker 1: expensive labor intensive to carry out. Uh, And so our
Speaker 1: question today, inspired by some recent stories in the news
Speaker 1: on this subject, is could we use a different method
Speaker 1: to try to eliminate invasive species on islands, a more
Speaker 1: forward thinking method. Possibly? The method in question is what's
Speaker 1: known as a gene drive. A gene drive? Right? Is this?
Speaker 1: Does this have to do with like donating denim? I think?
Speaker 1: I think when I was talking to my wife Rachel
Speaker 1: about this last night, she made the exact joke. High
Speaker 1: fives to Reachel. Yeah, not worded the same way, but
Speaker 1: it was. It was pants themed. So, uh, so what
Speaker 1: are gene drives? Well, let's sayward thinking it was pants themed. Sorry,
Speaker 1: sometimes so water gene Right, Well, let's say you want
Speaker 1: to spread an engineered gene throughout a population of animals.
Speaker 1: One commonly discussed example is that of a mosquito with
Speaker 1: a gene that prevents it from carrying the malaria parasite. Yeah,
Speaker 1: this is a thing that basically everyone can agree would
Speaker 1: be a plus exactly. I mean, it would be a
Speaker 1: life saving innovation on a massive, worldwide scale. If mosquitoes
Speaker 1: can't carry the malaria parasite and transmitted to humans, just
Speaker 1: enormous amounts of mortality and human misery around the world
Speaker 1: could be prevented. Yeah, if you if you do not remember,
Speaker 1: mosquitoes actually are the creature that kill the most humans,
Speaker 1: perhaps other than humans, every year indirectly by being the
Speaker 1: carriers of right. Yeah, I guess it's the malaria parasite.
Speaker 1: But yeah, and screw that parasite anyway, So it's really bad.
Speaker 1: But yeah, So if you can create a mosquito in
Speaker 1: the lab with a gene that says, sorry, malaria parasite
Speaker 1: can't survive in me, I won't transmit it. Uh, that
Speaker 1: would be great, But then you face another problem. Let's
Speaker 1: say you've created this mosquito. How do you get that
Speaker 1: mosquito to become the new mosquito to take over wild
Speaker 1: mosquito populations? Because just just releasing a single certainly a
Speaker 1: single creature, but even even a large number of creatures
Speaker 1: into the wild doesn't necessarily mean that their genetics will
Speaker 1: will propagate out over an entire population. Right, So let's
Speaker 1: look at what happens, I mean, how do sexually reproducing
Speaker 1: animals get their genes. Usually what happens is that a
Speaker 1: male and female mate and their offspring each received fifty
Speaker 1: percent of each parents genes, you get a recombinant mix
Speaker 1: of the two, mostly at random. So in the case
Speaker 1: of each gene location in the chromosomes, you have a
Speaker 1: fifty percent chance of inheriting the allele from your mom
Speaker 1: and a fifty percent chance of getting the allele from
Speaker 1: your dad. So if this anti malaria mosquito manages to mate,
Speaker 1: half of its offspring will carry the anti malaria gene,
Speaker 1: and are the ones that do carry it, only half
Speaker 1: of their offspring will carry it. Uh, there's this population
Speaker 1: genetics barrier to the spread of this anti malaria technology.
Speaker 1: And this is assuming that the trait has a neutral
Speaker 1: effect on survival and reproduction, or even confers an advantage
Speaker 1: so that the carrier mosquitoes have more offspring than the
Speaker 1: non carriers. Yeah, that's not guaranteed. It could be in
Speaker 1: some way detrimental to to the continuation of the species,
Speaker 1: to to reproducibility exactly. So if it's detrimental, we can
Speaker 1: probably expect it to dwindle and eventually disappear. Even if
Speaker 1: it's beneficial, it's only going to spread very slowly. It's
Speaker 1: gonna might become widespread among mosquitoes in the long run,
Speaker 1: but it will take a really long time and it's
Speaker 1: still not guaranteed. So if you want to be sure
Speaker 1: that it does become widespread among wild mosquitoes, you'd have
Speaker 1: to release just an absolutely gargantuan number of engineer mosquito
Speaker 1: individuals into the wild with this gene And that's not
Speaker 1: a great plan either. That doesn't sound like a fun
Speaker 1: way to spend my Saturday. Yeah, Like, if somebody comes
Speaker 1: to you and says, hey, we're going to release five
Speaker 1: hundred trillion engineered mosquitoes into a lot of help into
Speaker 1: your neighborhood, I feel like thanks. Uh. So this is
Speaker 1: where the gene drive comes in. So a gene drive
Speaker 1: is a system for biasing the inheritance of genes that
Speaker 1: is pretty simple, but the goal is towards altering an
Speaker 1: entire interbreeding population in a short amount of time. So
Speaker 1: at the microscopic level, the gene drive is literally just
Speaker 1: a heritable molecular mechanism, like a tiny molecule machine that's
Speaker 1: attached to your DNA that gets passed on from parent
Speaker 1: to offspring and ensures that a selected gene will be
Speaker 1: inherited with a near one certainty during sexual reproduction. Yeah,
Speaker 1: and well we'll talk a little bit about that mechanism
Speaker 1: in a minute. It but let's just let's just give
Speaker 1: give kind of an example of how this flows out
Speaker 1: to a population. Okay, So again, let's imagine that you
Speaker 1: want to use a gene drive to spread this anti
Speaker 1: malaria gene among a wild population of mosquitoes. We can assume,
Speaker 1: for the sake of an example, that the mosquito that
Speaker 1: mates produces four offspring that are able to reproduce into
Speaker 1: the next generation. This is not based on real mosquito
Speaker 1: browd numbers. I just picked a random number and it
Speaker 1: was four. Four is a nice easy one to multiply.
Speaker 1: So with half of them inheriting the gene, on average,
Speaker 1: one hundred percent of them or close to it will
Speaker 1: inherit the anti malaria gene. So now each of those
Speaker 1: four offspring I'll reproduce, and all of their offspring carried
Speaker 1: the anti malaria gene and the gene drive insurers continued inheritance.
Speaker 1: So then you've got sixteen and the next generation. Uh.
Speaker 1: And then if each of them has four offspring, you've
Speaker 1: got sixty four, and then two d and fifty six
Speaker 1: and then one thousand twenty four, and then four thousand,
Speaker 1: ninety six, and then sixteen thousand, three eight four, and
Speaker 1: by the sixteenth generation you have over a billion individual
Speaker 1: carriers of this gene. And so, okay, how this molecular
Speaker 1: mechanism works at a at a high level because I
Speaker 1: am not a geneticist. Um, it's it's actually a genetic
Speaker 1: power that is already seen in nature. There's uh this
Speaker 1: so called selfish genetic type of element of gene element. Okay,
Speaker 1: so these these genetic elements don't follow the usual law
Speaker 1: of averages of genetic inheritance inheritance um. When an egg
Speaker 1: is fertilized and one of the parents DNA contains a
Speaker 1: selfish element, that genetic bit targets the other parents parallel
Speaker 1: allele the other genetic bit and alters it. So zip
Speaker 1: zoom in this fertilized egg, you've got just about a
Speaker 1: heritable trait. The tricky bit here is taking the genes
Speaker 1: that make a selfish element and attaching them to the
Speaker 1: trait that you want to absolutely make sure it gets
Speaker 1: passed on. This this anti malaria trait um for for
Speaker 1: for example, and okay, science has been working on that
Speaker 1: part for over a decade, but it's been really rough
Speaker 1: going until our discovery of Crisper and cast nine came
Speaker 1: along over the past couple of years, and we did
Speaker 1: a whole episode about how that whole genetic toolkit works
Speaker 1: in April. The episode is called Editing Jeans with Crisper
Speaker 1: if you would like to go check it out. But
Speaker 1: in brief, crisper is another natural genetic process. It's it's
Speaker 1: part of some bacteria's adaptive immune system. So if a
Speaker 1: bacteria fights off a bacterium pardon me, fights off a
Speaker 1: particular virus that the crisper system will neatly snip out
Speaker 1: a wee bit of that viruss DNA is a sort
Speaker 1: of fingerprint or like a wanted poster, you can think
Speaker 1: of it and um. The system then attaches that snippet
Speaker 1: of d N d NA back into the bacterium's own DNA,
Speaker 1: so it keeps kind of like a catalog that it
Speaker 1: can refer back too. So if another virus with that
Speaker 1: bit of DNA ever comes a knocking at the bacterium's
Speaker 1: outer cell wall again, it will know immediately that the
Speaker 1: virus is bad news and can defend itself by dismantling
Speaker 1: part of the virus is d NA using a protein
Speaker 1: called CAST nine to do the manual labor. The bacterium
Speaker 1: can pass on it's wanted catalog to its offspring because
Speaker 1: it's part of its genetic code. So that is a
Speaker 1: super great way for bacteria to to live longer and better.
Speaker 1: It's a it's an amazing microscopic machine. It is. It is,
Speaker 1: and it's also super useful to us because one of
Speaker 1: the things that we've struggled with most in genetics classically
Speaker 1: has been how labor intensive and expensive it was to
Speaker 1: cut and paste to DNA together. But researchers figured out
Speaker 1: a way to apply the Crisper system to target basically
Speaker 1: any DNA they want, which means it's hella easy now
Speaker 1: to physically isolate and remove bits of genetic code and
Speaker 1: also to insert them into other bits of genetic Yeah,
Speaker 1: certainly relevant or relative to what it was before. Absolutely.
Speaker 1: So you you so you take this selfish element system
Speaker 1: and you combine it with our knowledge of the Crisper
Speaker 1: cutting pace system, and hazzah, you can pretty easily design
Speaker 1: a gene that will drive itself through a population just
Speaker 1: about as fast as that population can propagate. Yeah, and
Speaker 1: depending on the reproductive schedule of the organism in question,
Speaker 1: it can work with astonishing speed, like I've seen predictions
Speaker 1: that with a method method like this, scientists could stop
Speaker 1: the spread of malaria to humans within a couple of years.
Speaker 1: Whether so, whether or not these predictions are true, the
Speaker 1: gene drive is obviously an amazingly powerful tool for altering
Speaker 1: nature with a very low initial investment. But if we
Speaker 1: want to come back to the problem that we started
Speaker 1: discussing at the beginning of the episode, like invasive species
Speaker 1: on islands, how would you use a gene drive to
Speaker 1: fight a problem like this? Because in this case, the
Speaker 1: goal is not modifying an organism so that it does
Speaker 1: something different, like it doesn't become a disease vector. But
Speaker 1: the modification that we want is just something that would
Speaker 1: eradicate the species. Sure well, and in that case, really
Speaker 1: the modification that you want is something that does not reproduce. Right.
Speaker 1: So it's turns out it's not very hard to dream
Speaker 1: up a gene that, if delivered through a gene drive,
Speaker 1: can steer a population into extinction. In fact, it seems
Speaker 1: pretty easy. So let's say you have an island with
Speaker 1: a rat problem, and the rats are driving natural endemic
Speaker 1: species to extinction. Uh, here's the most common solution that
Speaker 1: scientists have come up with. You establish a gene drive
Speaker 1: for a trait that causes all of an animal's offspring
Speaker 1: to be male or or a vastly biased portion of
Speaker 1: them to be male. So imagine how this works on
Speaker 1: an island. With each generation, males make up a more
Speaker 1: disproportionate contingent of the total population, until eventually there are
Speaker 1: virtually no females for them to breed with, and the
Speaker 1: rats stop reproducing and disappear. Your rat problem on this
Speaker 1: island is gone. So there are some pros and cons
Speaker 1: to this method. Yeah, pros to this method. You don't
Speaker 1: need poison or traps. Don't need to dump thousands of
Speaker 1: pounds of rat poison out of helicopters all over the
Speaker 1: entire island and maybe accidentally poison other organisms and or
Speaker 1: set out traps that people have to collect and that
Speaker 1: you know, you maybe accidentally end up killing some of
Speaker 1: the animals you were trying to save getting your toe
Speaker 1: stuck in. Yeah, none of that. Good time. Another possible
Speaker 1: pro is that, so I mean a lot of the
Speaker 1: people who would be doing this eradication are probably animal lovers.
Speaker 1: It's not like they want the rats to suffer. They're
Speaker 1: just trying to keep native populations from going extinct. So
Speaker 1: this could be seen as a more humane way to
Speaker 1: eradicate invasive species. Instead of poisoning them killing them painfully,
Speaker 1: you just allow them to live out their lives without
Speaker 1: being able to make more are of them. They're very
Speaker 1: sexually frustrated lives. But but yes, other than that, it's
Speaker 1: it's definitely much more humane than poison. Yeah, I probably
Speaker 1: agree that that's true. But what if a reproduction prohibiting
Speaker 1: gene drive were to get loose in a non isolated population,
Speaker 1: Because the way it works on the island is it
Speaker 1: just keeps multiplying. This gene spreads through more and more
Speaker 1: the population until there's nothing left and then the rats
Speaker 1: die off. What if rats carrying this gene got to
Speaker 1: the mainland. What if they hitchhike on the sharks that
Speaker 1: are humanity and get back over Whoops, Because then they
Speaker 1: could breed with rats on the mainland and essentially start
Speaker 1: this entire process over except for the entire world. That's
Speaker 1: not good because you could accidentally create worldwide extinction. And
Speaker 1: as much as we don't like rats. I don't think
Speaker 1: we want to drive them to worldwide extinction. There would
Speaker 1: certainly be other repercussions involved there as as again we
Speaker 1: have talked about before on the show. At any time
Speaker 1: that you that you interrupt an ecosystem, it's going to
Speaker 1: have wide ripples that you can't really predict because ecosystems
Speaker 1: are so complex and convoluted. Uh. The other con that I,
Speaker 1: you know, just wanted to mention because of me, is
Speaker 1: that this is literally one of the things that led
Speaker 1: to everyone except Jeff Goldblum and I guess a few
Speaker 1: other people dying in Jurassic Park because all the dinosaurs
Speaker 1: were female, and no one remember that the frogs that
Speaker 1: they use the genetic code from to help build the
Speaker 1: dinosaurs could switch sexes when the population lagged. And Okay, look,
Speaker 1: what I'm saying is not that introducing gene drives into
Speaker 1: a population of rats is going to lead to all
Speaker 1: of us getting eaten or hunted for sport or whatever
Speaker 1: by dinosaurs. I'm just saying, you know, I mean, do
Speaker 1: you want to do the line Joe, Life finds a
Speaker 1: way that thing right there, It certainly does. It smashes
Speaker 1: through barriers, painful maybe sometimes even dangerously, but there it is.
Speaker 1: And you know that though, I think about Jurassic Park now,
Speaker 1: and it seems that they had it backwards. So if
Speaker 1: they were trying to produce an population of animals that
Speaker 1: couldn't breed, and then they had all females, it seems
Speaker 1: like just one male could really mess up that whole system.
Speaker 1: What they should have done is have a population of
Speaker 1: all males. Then if you had just one female get
Speaker 1: in there, that wouldn't be good, but it wouldn't you know,
Speaker 1: have a runaway effect. Absolutely. Uh. I think I think
Speaker 1: the reason that they did it that way, that the
Speaker 1: explanation for this plot hole was that it was it's
Speaker 1: it's easier to turn off genetically the male chromosome than
Speaker 1: it is too because because all embryos starts females, they
Speaker 1: did the the easy thing instead of the smart thing.
Speaker 1: What do you know, created a gaping, gaping plot hole. Uh.
Speaker 1: So other general thoughts about gen drives, I mean, we
Speaker 1: should definitely end by by emphasizing I think the uh,
Speaker 1: the concerns and very serious caution that that people are
Speaker 1: saying we should exercise with this technology for very good reason.
Speaker 1: Oh yeah, because because it is so exciting, Like the
Speaker 1: concept is is so dynamic and interesting, but also yeah,
Speaker 1: like this is one that basically every researcher that I've
Speaker 1: read anything from who is working with gene drives right
Speaker 1: now is like, let's apply some great safety breaks for
Speaker 1: a while, y'all. This is one of the most powerful
Speaker 1: and one of the scariest tools we've ever invented. I think, So,
Speaker 1: what could gene drives do besides halting the spread of
Speaker 1: disease through vector modification or eradicating invasive species. I'm sure
Speaker 1: we could actually come up with tons of different ways
Speaker 1: to apply a technology like this. Here's one I thought
Speaker 1: of that might be reduced released into the wild. Uh.
Speaker 1: I don't know why I said I thought of this,
Speaker 1: This is one I read about. I wasn't trying to
Speaker 1: claim claim credit there. Uh. What it was was herbicide
Speaker 1: pesticide resistance reversal. So often organisms that hamper crop development,
Speaker 1: like weeds and insect pests, for instance, develop resistance to
Speaker 1: the safest chemical means of keeping them off our food crops.
Speaker 1: One example weeds resistant to the herbicide glyph asade. So
Speaker 1: with gene drives, you could spread a gene ensuring vulnerability
Speaker 1: to conventional herbicides among the wild population, not not eradicating them,
Speaker 1: just essentially undoing the resistance that they've evolved to the
Speaker 1: poisons we used to keep them off of our food. Yeah,
Speaker 1: and and that could help us as a side effect
Speaker 1: or not a side effect, like as a as a
Speaker 1: cascade effect, minimize the different types of herbsides and pesticides
Speaker 1: that are used, focusing on the ones with the fewest
Speaker 1: side effects, which would be real good times for other
Speaker 1: creatures that interact with those herbicides and pesticides that are
Speaker 1: not as hardy, like saybes, Yeah, you don't want to
Speaker 1: be constantly upping the potency of your arsenal to protect
Speaker 1: your crops because upping that potency probably is just doing
Speaker 1: more and more damage. Sure, and you know so or
Speaker 1: or or I don't know, like like maybe we could
Speaker 1: use a similar We could use the technology to make
Speaker 1: bees more resistant to those poisons. Although that seems like
Speaker 1: a I mean more poisons, I think is not the
Speaker 1: point of all of this. I did want to put
Speaker 1: in that that it would, though be harder to propagate
Speaker 1: a gene drive through most crop populations themselves, because most
Speaker 1: crops don't reproduce sexually, and and this is perhaps obviously,
Speaker 1: but it should be stated a technology that only works
Speaker 1: in sexually reproducing populations. A lot of crops are made
Speaker 1: by very controlled seed populations, like cloning. Essentially yeah, plants. Okay,
Speaker 1: I don't think I actually knew that fact. That's interesting. Yeah,
Speaker 1: a lot of cuttings are used, which is essentially a
Speaker 1: way of cloning. That makes sense. Uh So another question
Speaker 1: I know people are wondering about. Could humans be eradicated
Speaker 1: via gene drive? An important question, so it's relevant to
Speaker 1: me if nobody was paying attention and you had a really,
Speaker 1: really long time to do it, I guess, But in reality,
Speaker 1: probably not, because gene drives rely on fast reproductive cycles
Speaker 1: to spread through wild populations, and humans and other large
Speaker 1: mammals that have multi year reproductive cycles would take centuries
Speaker 1: before the gene drive became widespread, and by then we
Speaker 1: would probably have detected the problem and done something about it,
Speaker 1: So I wouldn't. That's not the big worry. But does
Speaker 1: that mean we should not worry? No, no, no, no no.
Speaker 1: This is something we need to be incredibly cautious and
Speaker 1: concerned about because so maybe they won't affect us, But
Speaker 1: could gene drives released into the wild cause some very
Speaker 1: bad outcomes that affect other animals and affect us indirectly. Absolutely,
Speaker 1: this is a very powerful and very potentially dangerous technology,
Speaker 1: and among any sexually reproducing species with rapid generational turnover,
Speaker 1: a gene drive accidentally released into the wild could cause
Speaker 1: worldwide alteration, inter extinction, and possibly in ways that we
Speaker 1: cannot imagine. You know, because genes do sometimes jump from
Speaker 1: one species to another, from from one phylum to another.
Speaker 1: There's there's lots of examples of that out in nature. Yeah,
Speaker 1: so what if, for example, you have uh, usually we
Speaker 1: see the dividing line between species as being you know,
Speaker 1: animals that won't naturally interbreed with one another, but sometimes
Speaker 1: animals do cross the line and it can surprise us. Yeah. Yeah,
Speaker 1: So for those reasons, some scientists are recommending that for
Speaker 1: for any gene drive designed, a either reversal drive or
Speaker 1: an an immunization drive be designed in parallel. A reversal
Speaker 1: drive would act against the original drive, cutting it out
Speaker 1: of the population if something started to go wrong, and
Speaker 1: an immunization drive would spread through the population alongside the
Speaker 1: original drive, preventing later generations from inheriting the original um,
Speaker 1: which you know wouldn't stop all of the potential damage,
Speaker 1: but it would certainly emitted. Yeah. One thing I have heard,
Speaker 1: one of the sort of glimmers of hope, is that
Speaker 1: you could potentially just design an antidote drive essentially right,
Speaker 1: exactly what I think you're talking about. Yeah, with with
Speaker 1: the reverse, with the reversal drive. Yeah, um so so,
Speaker 1: so it's not like if it got loose, there's nothing
Speaker 1: we know we could do to stop it. But that
Speaker 1: doesn't mean we should be cavalier about it either, yeah. Yeah.
Speaker 1: And researchers furthermore are working on a way to cut
Speaker 1: off gene drives after a few generations, like naturally in
Speaker 1: the wild by by designing in a sort of fail safe.
Speaker 1: A team out of M I T specifically has conceptualized
Speaker 1: a daisy chain effect is what they're calling it, and
Speaker 1: the idea is that's okay, you split the genetic information
Speaker 1: that you're testing into three packages. Part A can only
Speaker 1: paste itself into wild DNA if part B is present.
Speaker 1: Part B, meanwhile, can only paste itself into wild DNA
Speaker 1: if parts C is present and parts C here's the
Speaker 1: critical part is a normal gene will only be inherited
Speaker 1: about fifty of the time. So if you release creatures
Speaker 1: with with all three parts into a natural population, the
Speaker 1: next generation will have well, we'll all have A and B,
Speaker 1: but only about half of them will have C. So
Speaker 1: although the gene drive will persist out for a few generations,
Speaker 1: eventually parts C will largely die out, and then B
Speaker 1: and then A and and this this could allow for
Speaker 1: a safer way to introduce a localized, temporary gene drive
Speaker 1: into the wild. Interesting um hypothetically if it works as planned,
Speaker 1: if life does not find a way right, So, yeah,
Speaker 1: don't run away with any of this thinking like, oh,
Speaker 1: we're we're okay, then don't need to worry about that.
Speaker 1: Do it tomorrow. This is something you should be thinking
Speaker 1: about and everybody should be paying attention to, because it's
Speaker 1: yet another one of these things where recent advances in
Speaker 1: genetics I think, are are catching people off guard. They're
Speaker 1: coming faster than people are coming up with ways to
Speaker 1: form ethical opinions about though right, largely because of this
Speaker 1: Crisper process, which is I mean super amazing but but
Speaker 1: also right, has just pulled entirely the breaks off of
Speaker 1: the system really in terms of what we can do
Speaker 1: with genetics. Yeah, um, and so so I think we
Speaker 1: should definitely pay heed to the scientists who are urging
Speaker 1: caution and uh and very careful treading on this. I'm
Speaker 1: not necessarily opposed to gene drive research, and I think
Speaker 1: it's a good thing to be studying, but it's the
Speaker 1: kind of thing that you have to study extremely carefully.
Speaker 1: So you know, what if you're you're just working on
Speaker 1: gene drive research and you've got a lab full of
Speaker 1: insects and one of them escapes the lab, whoops. Uh.
Speaker 1: So yeah, there have been I know, people have tried
Speaker 1: different methods of controlling this, like, for example, only experimenting
Speaker 1: with gene drives in organisms in labs that are in
Speaker 1: places where those organisms don't naturally live, so if one
Speaker 1: did escape somehow, it wouldn't find anything to breed with. Sure, yes,
Speaker 1: and and all the gene drives to the polar self.
Speaker 1: And don't experiment on penguins at all. Ye are penguins
Speaker 1: in in the polars? I don't remember. I always get
Speaker 1: this mixed time. I think they're around the water anyway, Yes, caution,
Speaker 1: yeah exactly. So, I mean it's really cool it's really cool,
Speaker 1: but caution. Yeah. Anyway, there's been a bunch of a
Speaker 1: bunch of writing about this in the science press lately
Speaker 1: and UH, and it's something that's definitely worth keeping up with.
Speaker 1: I would just recommend googling gene drives and UH and
Speaker 1: news around this subject if you want to keep abreast
Speaker 1: of this developing topic. Yeah. Uh. If you have any
Speaker 1: specific questions about it, then feel free to ask us.
Speaker 1: You can get in touch with us are in multiple ways.
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