i've told you guys this, the outbreeding issues are not genetic (though they can be sociological). people have looked for several decades (from the late henry harpending to pontus skoglund) at evidence of purification of outgroup alleles like you see with neanderthals in modern human backgrounds by comparing african hunter-gatherers to outgroups (eg san bushmen who have eurasian DNA from nilotic and afrikaner). there is no evidence of this.
also, i figured the last decade of ancient DNA would clue you guys in on this; outbreeding is how most modern lineages emerged. the pairwise Fst btwn WHG and EFF is 0.10, same value as btwn han chinese and n europeans.
a word of constructive criticism: aporia should focus on open controversies and take my judgement on things that i know about. i've been in this game longer than most of you :)
The negative effects of outbreeding should disappear through purifying selection after several generations. Consequently, remote Neandertal admixture isn't an issue. Nor is Eurasian DNA in Khoisan populations. Nor is East Asian admixture in Central Asia. That's why we need to examine first-generation effects, particularly effects on fertility. There may be other "canaries in the coal mine" but I'm not aware of any.
Yes, a lot of people have mused on this issue, like Ernst Mayr. But there have been very few controlled studies. In fact, there have been only two: the Icelandic one and the Danish one. I strongly suspect that the rise of male infertility is due to the increase in outbreeding, but that possible cause has to be disentangled from the possible cause of environmental estrogens. In my humble opinion, the outbreeding explanation is a better match for the epidemiology, but I could be wrong. This is an ongoing debate, and, incidentally, I'm not the academic who began it.
I realize this is a sensitive issue, and in some cases a deeply personal one. Of course. But it's not my role to tell people what they want to hear. Charles Darwin married his first cousin, yet that didn't stop him from investigating the deleterious effects of inbreeding.
i've been looking into this for a long time. there is no persuasive genetic evidence. ppl can be edgy all they want (mostly anonymously from what i can see in these comments), but if the evidence does not fit, you must acquit. just move on. you can oppose mass immigration for cultural reasons. adding explanations that do not hold water just make ppl think you are cranks
(this is the second time this issue has come up on aporia, and this will be the last time i address it, i have better things to do)
I have a feeling that the people who are incline to do IVF + embryo selection to get high IQ children are not people looking only to marry and have kids with their 3rd or 4th cousins. Starting with myself.
If the criteria is to get the highest IQ and lowest disease risk, then the polygenic scores will tell us exactly that, regardless of who the person is. I wouldn't start this process by looking at my 3rd cousins. It will be from people I went to university or at work where I can evaluate their health and IQ easily. And verify that later with actual polygenic scores.
The Flynn effect occurred because people got better at test-taking. During the 20th century, students were prepped to take the SAT and ACT tests, so this made them more prepared to take the IQ test and were less nervous during the test. This led to an increase in registered IQ during the 20th century because the subjects were more comfortable taking tests, concealing an actual cognitive decline.
I think that the main difference lands on Outbreeding + Weak Selection (With modernity, vacines, etecetera) are able to create and accumulate genetic problems including fertility problems.
Is highly probable that with a Strong selection + Outbreeding generates some differential genetic combinations that can manifest in small groups and be more dominant as time goes without any effect on health or fertility of the population.
I wonder if in part, somewhat, if you are breeding with people dissimilar it tells the female body that there has been a war and you are breeding with the arrivals. Ie, like you are being raped by a foreign tribe and maybe your genes are programmed to die out more readily in that scenario. As your genes caused the loss of the males in the environment. Interesting brain trip I went down with this. Excellent article. Thoroughly enjoyed.
Fascinating- thank you. Do you think hybridization in humans - coupled with severe evolutionary pressures - could accelerate fitness for those that are positioned at the geographical crossroads of different human populations?
If you compare a global map of exogamous countries with a global map of the average IQ of nations, a pattern will emerge. The more exogamous societies have a higher average/median IQ.
i've told you guys this, the outbreeding issues are not genetic (though they can be sociological). people have looked for several decades (from the late henry harpending to pontus skoglund) at evidence of purification of outgroup alleles like you see with neanderthals in modern human backgrounds by comparing african hunter-gatherers to outgroups (eg san bushmen who have eurasian DNA from nilotic and afrikaner). there is no evidence of this.
also, i figured the last decade of ancient DNA would clue you guys in on this; outbreeding is how most modern lineages emerged. the pairwise Fst btwn WHG and EFF is 0.10, same value as btwn han chinese and n europeans.
a word of constructive criticism: aporia should focus on open controversies and take my judgement on things that i know about. i've been in this game longer than most of you :)
Razib,
The negative effects of outbreeding should disappear through purifying selection after several generations. Consequently, remote Neandertal admixture isn't an issue. Nor is Eurasian DNA in Khoisan populations. Nor is East Asian admixture in Central Asia. That's why we need to examine first-generation effects, particularly effects on fertility. There may be other "canaries in the coal mine" but I'm not aware of any.
Yes, a lot of people have mused on this issue, like Ernst Mayr. But there have been very few controlled studies. In fact, there have been only two: the Icelandic one and the Danish one. I strongly suspect that the rise of male infertility is due to the increase in outbreeding, but that possible cause has to be disentangled from the possible cause of environmental estrogens. In my humble opinion, the outbreeding explanation is a better match for the epidemiology, but I could be wrong. This is an ongoing debate, and, incidentally, I'm not the academic who began it.
I realize this is a sensitive issue, and in some cases a deeply personal one. Of course. But it's not my role to tell people what they want to hear. Charles Darwin married his first cousin, yet that didn't stop him from investigating the deleterious effects of inbreeding.
many ppl here fancy themselves politically incorrect and fearsome, but i've been in this game a long time. look at question #5 in 2005 https://www.gnxp.com/blog/2005/12/10-questions-for-armand-m-leroi.php
i've been looking into this for a long time. there is no persuasive genetic evidence. ppl can be edgy all they want (mostly anonymously from what i can see in these comments), but if the evidence does not fit, you must acquit. just move on. you can oppose mass immigration for cultural reasons. adding explanations that do not hold water just make ppl think you are cranks
(this is the second time this issue has come up on aporia, and this will be the last time i address it, i have better things to do)
I have a feeling that the people who are incline to do IVF + embryo selection to get high IQ children are not people looking only to marry and have kids with their 3rd or 4th cousins. Starting with myself.
If the criteria is to get the highest IQ and lowest disease risk, then the polygenic scores will tell us exactly that, regardless of who the person is. I wouldn't start this process by looking at my 3rd cousins. It will be from people I went to university or at work where I can evaluate their health and IQ easily. And verify that later with actual polygenic scores.
The Flynn effect occurred because people got better at test-taking. During the 20th century, students were prepped to take the SAT and ACT tests, so this made them more prepared to take the IQ test and were less nervous during the test. This led to an increase in registered IQ during the 20th century because the subjects were more comfortable taking tests, concealing an actual cognitive decline.
I've wondered how Morman inbreeding could produce such attractive and intelligent peoples (minus the temple garments).
I think that the main difference lands on Outbreeding + Weak Selection (With modernity, vacines, etecetera) are able to create and accumulate genetic problems including fertility problems.
Is highly probable that with a Strong selection + Outbreeding generates some differential genetic combinations that can manifest in small groups and be more dominant as time goes without any effect on health or fertility of the population.
I wonder if in part, somewhat, if you are breeding with people dissimilar it tells the female body that there has been a war and you are breeding with the arrivals. Ie, like you are being raped by a foreign tribe and maybe your genes are programmed to die out more readily in that scenario. As your genes caused the loss of the males in the environment. Interesting brain trip I went down with this. Excellent article. Thoroughly enjoyed.
Fascinating- thank you. Do you think hybridization in humans - coupled with severe evolutionary pressures - could accelerate fitness for those that are positioned at the geographical crossroads of different human populations?
Thank you - armchair geneticist here
If you compare a global map of exogamous countries with a global map of the average IQ of nations, a pattern will emerge. The more exogamous societies have a higher average/median IQ.
I want to see Peter's reply but can't see it.
The study results were exciting but not what I expected.