4 ms·

The males that produce only male offspring that survive are identical to males that don't. Both types of matings produce eggs that hatch larva. The females di

The males that produce only male offspring that survive are identical to males that don't. Both types of matings produce eggs that hatch larva. The females die before the eggs hatch, so they never see the offspring, thus it's difficult for them to "learn" anything. The modified males produce only viable male offspring, so no female offspring survive to allow the evolutionary mechanism to work - all the females that live to adulthood are born from female and male parents that were unmodified, so there's no chance of the "modified" genes affecting female numbers.

beerandt 7y ago
I think the main concern isn't the modified genes being passed on, but the genetic results of selective pressure against a population with those modified genes. Pulling this out of thin air, but what if a female had a mutation that allows mating with multiple males. Or multiple batches of eggs before they die. This trait would have a big advantage in a population of mostly sterile males, but also: You'd inadvertantly create a super breeder lineage. Stealing from the obvious: in Jurassic Park, it's the equivalent of selecting for dinos that can change sex to reproduce. The scientists didn't insert that particular trait, but ended up accidently selecting for it, by pressure in the form of a single sex population. (I'm not suggesting spontaneous sex change in mosquitos, just inadvertent selection that might benefit their reproductive ability.) Maybe I'm way off. It just seems like there's more than one way this could go wrong.
- Accujack 7y ago
  >Pulling this out of thin air, but what if a female had a mutation that allows mating with multiple males. Or multiple batches of eggs before they die. True, but your example essentially says "What if a mutation happened that completely negated the limiting effect of the genetic modifications that have been done." If something this unlikely happens to the moth, of course it's going to change everything. If it happened to a non genetically engineered population of moths, it would change everything for them, too. If I recall the plot of that book, the scientists in question made the mistake of wholesale copying strings of frog DNA to fill in "gaps" in the Dino DNA they were reconstructing. Apart from being ludicrous from a scientific point of view, the idea is that they copied genes that allowed for a sex change by the organism possessing those genes. It wasn't anything to do with evolution. Evolution doesn't work on individuals at all, it works on populations over many generations. Until the "dinosaurs" in the story actually reproduced, evolution had no effect on them - it simply could not, because individuals don't change to respond to selection pressure... they either reproduce successfully or don't. Dinos that had been engineered to not reproduce couldn't evolve at all, hence the "oops we copied the frog's sex change ability to the dinos" plot point.
  - beerandt 7y ago
    Yeah, this is why I hesitated to use that example. I get that the filing gaps in DNA and parthenogenesis aspects cloud the analogy. >"What if a mutation happened that completely negated the limiting effect of the genetic modifications that have been done." I wasn't suggesting mutation or evolution or inserted genes. I'm suggesting unintentional selection for a trait already present in the wild gene pool. Combined with the bottleneck intentionally created by the experiment, it could lead to the artificial magnification of a trait (amongst the surviving population) that's the opposite of what the experiment is trying to accomplish. It also makes it likely, not unlikely. The question will be what traits end up being selected for, and how drastically they will affect the genetic fitness of the gene pool. Similar to how antibiotic resistance emerges without ever inserting any specific genetics. Obviously without the benefit of horizontal exchange, but perhaps with other methods of genetic exchange... As the mosquito experiments seem to prove so far, with "infertile" males leaving remnants of their DNA in the surviving population. Which, being bred and distributed, is a different type of horizontal exchange, I suppose. Sidenote: While I wasn't initially including parthenogenic reproduction in my thoughts above, maybe I should have. Recent studies support the parthenogenic reproduction in a surprising number of zw species, including Komodo dragons, mourning geckos, whiptail lizards, some birds, snakes, and... moths. It's pretty fascinating, and more proof that Crichton knew what he was talking about, even if he didn't always fully grasp it. https://en.m.wikipedia.org/wiki/Lepidodactylus_lugubris https://en.m.wikipedia.org/wiki/Lepidodactylus_lugubris https://en.m.wikipedia.org/wiki/Parthenogenesis https://en.m.wikipedia.org/wiki/Parthenogenesis https://en.m.wikipedia.org/wiki/Parthenogenesis_in_squamata https://en.m.wikipedia.org/wiki/Parthenogenesis_in_squamata https://en.m.wikipedia.org/wiki/ZW_sex-determination_system https://en.m.wikipedia.org/wiki/ZW_sex-determination_system

beerandt 7y ago

I think the main concern isn't the modified genes being passed on, but the genetic results of selective pressure against a population with those modified genes. Pulling this out of thin air, but what if a female had a mutation that allows mating with multiple males. Or multiple batches of eggs before they die. This trait would have a big advantage in a population of mostly sterile males, but also: You'd inadvertantly create a super breeder lineage. Stealing from the obvious: in Jurassic Park, it's the equivalent of selecting for dinos that can change sex to reproduce. The scientists didn't insert that particular trait, but ended up accidently selecting for it, by pressure in the form of a single sex population. (I'm not suggesting spontaneous sex change in mosquitos, just inadvertent selection that might benefit their reproductive ability.) Maybe I'm way off. It just seems like there's more than one way this could go wrong.

Accujack 7y ago
>Pulling this out of thin air, but what if a female had a mutation that allows mating with multiple males. Or multiple batches of eggs before they die. True, but your example essentially says "What if a mutation happened that completely negated the limiting effect of the genetic modifications that have been done." If something this unlikely happens to the moth, of course it's going to change everything. If it happened to a non genetically engineered population of moths, it would change everything for them, too. If I recall the plot of that book, the scientists in question made the mistake of wholesale copying strings of frog DNA to fill in "gaps" in the Dino DNA they were reconstructing. Apart from being ludicrous from a scientific point of view, the idea is that they copied genes that allowed for a sex change by the organism possessing those genes. It wasn't anything to do with evolution. Evolution doesn't work on individuals at all, it works on populations over many generations. Until the "dinosaurs" in the story actually reproduced, evolution had no effect on them - it simply could not, because individuals don't change to respond to selection pressure... they either reproduce successfully or don't. Dinos that had been engineered to not reproduce couldn't evolve at all, hence the "oops we copied the frog's sex change ability to the dinos" plot point.
- beerandt 7y ago
  Yeah, this is why I hesitated to use that example. I get that the filing gaps in DNA and parthenogenesis aspects cloud the analogy. >"What if a mutation happened that completely negated the limiting effect of the genetic modifications that have been done." I wasn't suggesting mutation or evolution or inserted genes. I'm suggesting unintentional selection for a trait already present in the wild gene pool. Combined with the bottleneck intentionally created by the experiment, it could lead to the artificial magnification of a trait (amongst the surviving population) that's the opposite of what the experiment is trying to accomplish. It also makes it likely, not unlikely. The question will be what traits end up being selected for, and how drastically they will affect the genetic fitness of the gene pool. Similar to how antibiotic resistance emerges without ever inserting any specific genetics. Obviously without the benefit of horizontal exchange, but perhaps with other methods of genetic exchange... As the mosquito experiments seem to prove so far, with "infertile" males leaving remnants of their DNA in the surviving population. Which, being bred and distributed, is a different type of horizontal exchange, I suppose. Sidenote: While I wasn't initially including parthenogenic reproduction in my thoughts above, maybe I should have. Recent studies support the parthenogenic reproduction in a surprising number of zw species, including Komodo dragons, mourning geckos, whiptail lizards, some birds, snakes, and... moths. It's pretty fascinating, and more proof that Crichton knew what he was talking about, even if he didn't always fully grasp it. https://en.m.wikipedia.org/wiki/Lepidodactylus_lugubris https://en.m.wikipedia.org/wiki/Lepidodactylus_lugubris https://en.m.wikipedia.org/wiki/Parthenogenesis https://en.m.wikipedia.org/wiki/Parthenogenesis https://en.m.wikipedia.org/wiki/Parthenogenesis_in_squamata https://en.m.wikipedia.org/wiki/Parthenogenesis_in_squamata https://en.m.wikipedia.org/wiki/ZW_sex-determination_system https://en.m.wikipedia.org/wiki/ZW_sex-determination_system