Souzai Saishuka no Isekai Ryokouki - Ch. 52

[popo53414]

wow

 

[vodspod]

Technically it isn't destroying their genes, it is just slowly breeding out random genes from the population due to random genes being passed down. Since some genes suppress other genes those suppressed genes will start to show effects on the body as the genes suppressing them are not present. Since those genes were suppressed they were not commonly effected by natural selection, so they have a much higher chance of being detrimental. Having an outside population interbreeding with the isolated population can help reintroduce missing genes to the isolated population, but due to the genetic drift and changes from the difference in genes, it is possible that they are no longer able to interbreed. In such cases they would be considered separate species, but that would have required many generations to occur, and it tends to take longer than the problem caused by inbreeding to surface, but both would be effected based on the population of the isolated group.

 

[Amariithynar]

Technically it isn't destroying their genes, it is just slowly breeding out random genes from the population due to random genes being passed down. Since some genes suppress other genes those suppressed genes will start to show effects on the body as the genes suppressing them are not present. Since those genes were suppressed they were not commonly effected by natural selection, so they have a much higher chance of being detrimental. Having an outside population interbreeding with the isolated population can help reintroduce missing genes to the isolated population, but due to the genetic drift and changes from the difference in genes, it is possible that they are no longer able to interbreed. In such cases they would be considered separate species, but that would have required many generations to occur, and it tends to take longer than the problem caused by inbreeding to surface, but both would be effected based on the population of the isolated group.

This and what I posted before (pg. 2 towards the bottom) are how it ACTUALLY works, but seems author doesn't know what they're talking about and is going with the generic "inbreeding is bad no matter what!" BS angle where even exogenetic effects are being attributed to genetics, here, along with ignoring how robust DNA has to be for longer-lived races, and how telomeres and genetic replicability in longer-lived species must be especially robust. Unless they pull a second psych-out and his judgement turns out to be incorrect and it's a combination of the magical energy as exogenetic factor combined with increased homogeneity meaning that they are more sensitive to it all and can be influenced more easily, anyways.

 

[CountryMage]

Wow. Talk about making a family tree into a family shrub. It doesn't protect as much.

Even shrubs have branches, this sounds like some Dr Seuss tree, with the twists and turns, but still only one limb.

 

[vodspod]

hmm the idea that magic may have a impact on the mutation of genes was something I hadn't considered. I don't think it likely would cause destruction of genes, but I wonder if it is possible it may either speed up mutation or acts as a mutation prevention system, probably both depending on the situation, but this would allow for more variance in the aspects I mentioned before. I would however say that regardless of its effect the inbreeding would have a likely strong negative effect on the population over enough generations. I think it is fine that the MC is wrong in this situation, since it will be unlikely that his conjecture will be distinctly proven correct over the modern model, and the outward appearance can look like his conjecture enough that it doesn't matter, given the fact that there are likely much different genes in a fantasy world compared to a non-magical world.

Would be great one time to see a story explore the purging of detrimental genes in a way similar to the method of plants or bacteria that can reproduce asexually, using the massive number of offspring to offset the issues with inbreeding, and actually turn it into a positive. I don't see an easy way to include such a concept into a story. Also the downside is possible lack of diversity of genes, but there are some plants that are able to handle such issue with more frequent mutation like that of the tumble weed, which originated in Russia, but was able to adapt so quickly that it is able to survive comfortably in deserts of the USA, although it still requires large flat land to survive due to its propagation method. I didn't research if the tumble weed reproduced asexually, but it has a feature that would be beneficial to species that do so.

 

[phorx]

I keep waiting for the MC to get a love interest of his own, maybe the missing sister will finally be the one. Seriously they make the point of him saying he wanted a cute partner and also being well endowed in Ch. 1 and since then he’s been a monk.

 

[kintoki9000]

This and what I posted before (pg. 2 towards the bottom) are how it ACTUALLY works, but seems author doesn't know what they're talking about and is going with the generic "inbreeding is bad no matter what!" BS angle where even exogenetic effects are being attributed to genetics, here, along with ignoring how robust DNA has to be for longer-lived races, and how telomeres and genetic replicability in longer-lived species must be especially robust. Unless they pull a second psych-out and his judgement turns out to be incorrect and it's a combination of the magical energy as exogenetic factor combined with increased homogeneity meaning that they are more sensitive to it all and can be influenced more easily, anyways.

So, I am curious because the elf went as far as having twins inbreeding. Would the inbreeding eventually narrow down the gene to where they are essentially making clones? Also, does inbreeding effect the telomere? Considering inbreeding increase the likelihood of recessive gene, which are often gene with defective traits, so far, the immunodeficiency trait showing up with the high elves make sense. The curse child is a bit more of a stretch, somehow producing children with missing part to extra part; although, the high infant mortality make me curious if SIDS has genetic link, but the jury seem to be out on that one. I vaguely remembered heavily inbred children are often sterile or maybe they just have significantly lower chance to breed due to complications.

 

[Amariithynar]

So, I am curious because the elf went as far as having twins inbreeding. Would the inbreeding eventually narrow down the gene to where they are essentially making clones? Also, does inbreeding effect the telomere? Considering inbreeding increase the likelihood of recessive gene, which are often gene with defective traits, so far, the immunodeficiency trait showing up with the high elves make sense. The curse child is a bit more of a stretch since they don't go into whether both system are functional. Though, I vaguely remembered heavily inbred children are often sterile or maybe they just have significantly lower chance to breed due to complications.

Inbreeding has no direct effect that we know of on telomeres in humans that I can find (not surprising, since a lot of human experimentation science is considered verboten, even when non-deleterious), but conditions and mental disorders, which can be caused by paired chromosomes that cause a trait to become active, can result in shortened telomeres, according to one small study. However, in at least a couple other studies, Mice and Sand Lizards groups both have much elongated telomeres due to their inbred status. In birds, telomere length in inbred populations (which is shortened instead of lengthened) leads to a greater focus on survival of self rather than survival of offspring, according to this study; this demonstrates that there can actually be a benefit to the shortened telomeres for a given population to survive, though it would still slowly suffer if it did not migrate or have another group migrate to them and increase the pool of available genes, as with other species that suffer inbreeding depression, as noted in this study.

As for effectively making clones? The pair would need to be entirely homozygous for every single gene to get a genetic clone on childbirth (which would be biologically impossible due to the fact that the Y chromosome is so different from the X, so could only be done via artificial means). To give a better understanding of this, a homozygous gene would be a gene expressed as "AA" or "aa", while a heterozygous gene would be "Aa"; if both parents have "Aa", then even though they match, the child could have "AA", "aa", or "Aa" like their parents, across every single gene.

Inbreeding also doesn't just increase likelihood of recessive genes, but of pairs of any genes; recessives (which are NOT intrinsically negative!), dominants (not intrinsically positive!), and co-dominant genes, as well. For example, with blood groups, the A allele is as ‘strong’ as the B allele. The A and B alleles are said to be co-dominant. Someone with one copy of A and one copy of B has the blood group AB. Someone with A blood actually has AO blood, and someone with B blood has BO blood, and the Rh factor determines if it is positive or negative, which is why O blood types are the most common; A and B type are recent (~20,000 years or so) developments.

Immunodeficiency as a trait would make far more sense in a shorter-lived race; remember that these species are meant to live for hundreds if not thousands of years at a time, so their immune system must be very robust to survive that long; they may be immunodeficient in terms of elves, but compared to humans or other shorter-lived species, they should still have godly immune systems.

As for fertility, this study from 1979 and this study from 2002 both indicate why inbreeding occurs; that close relative mating actually results in a boost to fertility for the couple. Where it can go awry is with consecutive consanguinous mating pairs, if they have a recessive gene that impedes fertility, since the rate of pairs increases with consecutive consanguinous pairing; however, given enough generations, such an allele would be outbred by those that are only carriers or do not carry it.

 

[bearybrown]

I guess this stems from pride of being High Elf rather than normal Elf.

Given the Elf country is monarchy, they probably got pressured into inbreeding by other High Elfs in the government.

And what most isekai trope is abandoning technological advancement when you could magic away your trouble.

 

[um3i]

One of the High Elves ancestor must've been isekai'd from Alabama long ago in the past huh

 

[isoycrazy]

One of the High Elves ancestor must've been isekai'd from Alabama long ago in the past huh

Instruments included.

 

[kintoki9000]

Inbreeding has no direct effect that we know of on telomeres in humans that I can find (not surprising, since a lot of human experimentation science is considered verboten, even when non-deleterious), but conditions and mental disorders, which can be caused by paired chromosomes that cause a trait to become active, can result in shortened telomeres, according to one small study. However, in at least a couple other studies, Mice and Sand Lizards groups both have much elongated telomeres due to their inbred status. In birds, telomere length in inbred populations (which is shortened instead of lengthened) leads to a greater focus on survival of self rather than survival of offspring, according to this study; this demonstrates that there can actually be a benefit to the shortened telomeres for a given population to survive, though it would still slowly suffer if it did not migrate or have another group migrate to them and increase the pool of available genes, as with other species that suffer inbreeding depression, as noted in this study.

As for effectively making clones? The pair would need to be entirely homozygous for every single gene to get a genetic clone on childbirth (which would be biologically impossible due to the fact that the Y chromosome is so different from the X, so could only be done via artificial means). To give a better understanding of this, a homozygous gene would be a gene expressed as "AA" or "aa", while a heterozygous gene would be "Aa"; if both parents have "Aa", then even though they match, the child could have "AA", "aa", or "Aa" like their parents, across every single gene.

Inbreeding also doesn't just increase likelihood of recessive genes, but of pairs of any genes; recessives (which are NOT intrinsically negative!), dominants (not intrinsically positive!), and co-dominant genes, as well. For example, with blood groups, the A allele is as ‘strong’ as the B allele. The A and B alleles are said to be co-dominant. Someone with one copy of A and one copy of B has the blood group AB. Someone with A blood actually has AO blood, and someone with B blood has BO blood, and the Rh factor determines if it is positive or negative, which is why O blood types are the most common; A and B type are recent (~20,000 years or so) developments.

Immunodeficiency as a trait would make far more sense in a shorter-lived race; remember that these species are meant to live for hundreds if not thousands of years at a time, so their immune system must be very robust to survive that long; they may be immunodeficient in terms of elves, but compared to humans or other shorter-lived species, they should still have godly immune systems.

As for fertility, this study from 1979 and this study from 2002 both indicate why inbreeding occurs; that close relative mating actually results in a boost to fertility for the couple. Where it can go awry is with consecutive consanguinous mating pairs, if they have a recessive gene that impedes fertility, since the rate of pairs increases with consecutive consanguinous pairing; however, given enough generations, such an allele would be outbred by those that are only carriers or do not carry it.

Awesome read, genetic fascinate me but also intimidating because biodiversity mean a mess of pattern that seemingly contradict each other.

I don't think the author mentioned the lifespan of high elves here, but they probably went with the usual assumption. Would the homogenous environment reduced the need of a robust immune system in evolutionary term? High elves here seem to live in only one environment. So that might make them vulnerable to immunodeficiency despite being long lifespan.

I did a surface search (Wikipedia) on how the whip tail lizard was able to reproduce asexual. If I understand it correctly, they managed to developed pairs of triplets chromosomes that enable genetic diversity despite asexually reproducing. No source on how they got there, though their mating habit suggest a sexual reproduction past. Basically, Takeru just need to add more chromosome to the high elves and they can bang their twins all they want.

Regarding the fertility studies, is that assuming the next few generation stop inbreeding? Or would the allele still get loss with ongoing inbreeding? Also would the number of offspring influence this? I am assuming the bigger the circle the more chance of the allele to get lost, but smaller circle would reduce that odd.

 

[Amariithynar]

Awesome read, genetic fascinate me but also intimidating because biodiversity mean a mess of pattern that seemingly contradict each other.

I don't think the author mentioned the lifespan of high elves here, but they probably went with the usual assumption. Would the homogenous environment reduced the need of a robust immune system in evolutionary term? High elves here seem to live in only one environment. So that might make them vulnerable to immunodeficiency despite being long lifespan.

I did a surface search (Wikipedia) on how the whip tail lizard was able to reproduce asexual. If I understand it correctly, they managed to developed pairs of triplets chromosomes that enable genetic diversity despite asexually reproducing. No source on how they got there, though their mating habit suggest a sexual reproduction past. Basically, Takeru just need to add more chromosome to the high elves and they can bang their twins all they want.

Regarding the fertility studies, is that assuming the next few generation stop inbreeding? Or would the allele still get loss with ongoing inbreeding? Also would the number of offspring influence this? I am assuming the bigger the circle the more chance of the allele to get lost, but smaller circle would reduce that odd.

Re: fertility studies, inbreeding could continue indefinitely and the allele would still be lost in pairings because a recessive that affects fertility negatively would mean less children overall, so those who descend from the same parents but are only carriers (Aa) or non-carriers (AA) would be outbreeding them until it vanishes almost entirely, if not entirely (e.g. the last couple with this recessive trait becomes unable to have children due to this gene expression, and due to the required pairings the carriers eventually get paired with non-carriers and eventually the trait vanishes; only a very long term possibility, because of the negative fertility value that such a recessive trait provides). This is actually what is slowly but surely happening with red hair and blue eyes, believe it or not, though they'll likely never entirely vanish, since they're not deleterious traits.

 

[kintoki9000]

Re: fertility studies, inbreeding could continue indefinitely and the allele would still be lost in pairings because a recessive that affects fertility negatively would mean less children overall, so those who descend from the same parents but are only carriers (Aa) or non-carriers (AA) would be outbreeding them until it vanishes almost entirely, if not entirely (e.g. the last couple with this recessive trait becomes unable to have children due to this gene expression, and due to the required pairings the carriers eventually get paired with non-carriers and eventually the trait vanishes; only a very long term possibility, because of the negative fertility value that such a recessive trait provides). This is actually what is slowly but surely happening with red hair and blue eyes, believe it or not, though they'll likely never entirely vanish, since they're not deleterious traits.

Interesting, so good news for endangered species. Although, it sound like you need a sufficiently robust population growth to loose any deleterious trait otherwise you still have the risk of it sticking around long enough to post a threat to the species. Funny enough, this has the implications that both the Adam & Eve, and Noah ark story has a possible path toward populating/repopulating the species, though they need extremely high breeding rate to sustain high enough population growth.

 

[Amariithynar]

Interesting, so good news for endangered species. Although, it sound like you need a sufficiently robust population growth to loose any deleterious trait otherwise you still have the risk of it sticking around long enough to post a threat to the species. Funny enough, this has the implications that both the Adam & Eve, and Noah ark story has a possible path toward populating/repopulating the species, though they need extremely high breeding rate to sustain high enough population growth.

to be perfectly honest, you just need a population growth rate above 1 to repopulate a species from a single pair; you'll just need to rely on radiation-caused mutations to alter alleles and get genetic variance, as happened with us (Sol as a star is at just the right distance and radiation output, in combination with Earth's atmosphere, to radiate the planet sufficiently to induce genetic mutations relatively reliably, but not so much as to result in instability and widespread death from exposure; very little genetic mutation would occur if we didn't have the constant low-level radiation we are exposed to, across all the lifeforms on the planet). It wouldn't be a very healthy gene pool for a very long time, though, and deleterious traits that pop up could easily wipe out the entire species before it's robust enough via mutation.

 

[hamdeo]

futanari elf
I can get behind that

 

[kintoki9000]

to be perfectly honest, you just need a population growth rate above 1 to repopulate a species from a single pair; you'll just need to rely on radiation-caused mutations to alter alleles and get genetic variance, as happened with us (Sol as a star is at just the right distance and radiation output, in combination with Earth's atmosphere, to radiate the planet sufficiently to induce genetic mutations relatively reliably, but not so much as to result in instability and widespread death from exposure; very little genetic mutation would occur if we didn't have the constant low-level radiation we are exposed to, across all the lifeforms on the planet). It wouldn't be a very healthy gene pool for a very long time, though, and deleterious traits that pop up could easily wipe out the entire species before it's robust enough via mutation.

So we need to induce mutations in the elf gene and raise their breeding rate to ensure there is enough of a buffer in the population number to survive any deleterious trait popping up. Now, I also wonder how epigenetic interact with deleterious traits, but I am too distracted with the idea of organizing elf orgies to save the species. Introducing outside genes maybe the simpler approach, however, the chinese finger trap solution approach also work, amusingly; the number of infant death gonna be hell on the psyche, but the possibly of simply outbreed the problem is funny, in an ironic sense. That being said, the linchpin in our conversation is that the baseline we are working with is not beyond saving. Feel like the elf breed slow enough to keep a lot of deleterious traits around to the point that the rate of infant mortality is just about to wipe them out.

 

[welcome2atlantis]

Elven Snot is an alchemy ingredient. Maybe.

 

[Kaitensatsuma]

"I can't explain it in detail"

I can

STOP FUCKING YOUR RELATIVES

 

[ZelousR2]

LOL! It really was inbreeding