Well, well, well…look what just got published in Nature


Nature‘s Journal of Human Genetics, that is. It’s a little piece titled “The collective effects of genetic variants and complex traits” by Mingrui Wang & Shi Huang, and the abstract is a bit odd.

Traditional approaches in studying the genetics of complex traits have focused on identifying specific genetic variants. However, the collective effects of variants have remained largely unexplored. Here, we evaluated whether traits could be influenced by the collective effects of variants across the entire protein coding-region of the genome or the entire genome. We studied the UK Biobank exome sequencing data of 167,246 individuals as well as the genome-wide SNP array data of 408,868 individuals. We calculated for each individual four different measures of genetic variation such as heterozygosity and number of variants and two different measures of the overall deleteriousness of all variants, and performed correlations with 17 representative traits that have been studied previously. Linear regression analysis was performed with adjustment for age, sex, and genetic principal components. The results showed a high correlation among the six different measures and an inverse association of two well-correlated traits (educational attainment and height) with the total number of all variants as well as the overall deleteriousness of all variants. We have also categorized the genes based on whether they are expressed in the brain and found that the association with educational attainment only held for the brain-expressed genes. No other traits examined showed a significant correlation with the brain-expressed genes. The study demonstrates that common traits could be studied by analyzing the overall genetic variation and suggests that educational attainment is inversely related to genetic variation.

Basically, the authors did some correlations on genomic data in a database, and they think they’ve found an inverse association — high genetic diversity in a population is coupled with low educational attainment. That is, coming from a region with high genetic diversity, like say, Africa, is correlated with, for instance, lower education. To which I would suggest that maybe that’s not surprising, that a continent that has been exploited and colonized for centuries, might have historical reasons for its people not having the advantages of the colonizer countries. But this paper wants to imply that that educational handicap is genetic.

Who reviewed this thing, anyway?

The authors use cautious wording in the abstract. The corresponding author, Shi Huang, is letting his racist freak flag fly on Twitter, though. He’s explaining how we’re supposed to interpret it.

Our latest paper. We show that genetic diversity is a new genetic factor in cognition, challenging the Out of Africa model. GD in human is under selection and has little to do with long evolutionary time or being human ancestors.

Excuse me? We’ve already gone from “educational attainment” to “cognition,” which is enough of a leap, but he’s somehow using these correlations to claim that modern humans did not evolve from African ancestors? Data not shown. Then, remarkably, he claims that genetic diversity is somehow selected for, that it has nothing to do with history or ancestry. Fucking data not fucking shown. This makes no sense. How does he get to this conclusion?

The San have the highest GD and the lowest cognition/civilization in humans and are believed to be the ancestors, i.e., Out of Africa. The only alternative is the maximum GD theory that GD has an upper limit, which is inversely proportional to brain function or complexity.

That this African group have high genetic diversity compared to other populations has been noted before, but “lowest cognition”? That’s absurd. This smacks of the discredited pseudo-scientific racism of Shockley and Lynn. “Lowest civilization”…again, how do you measure that? It’s more Western bias.

Then he completely demolishes his credibility. No one believes the San are the ancestors of other groups of people; they can’t be. They’re a modern human culture. They’re as derived as any other population on the planet, equally divergent from our shared distant ancestors. This guy is a professor of genetics? And there he goes again, blithely transforming “educational attainment” into “brain function or complexity.” That’s not valid.

The thread just goes haring after all kinds of absurdities.

This inverse relationship holds well among species (the higher the complexity, the lower the GD), which means that the highest GD of the San may be the reason for their cognition level being the lowest. The origin of humans may actually not be in Africa but in E Asia.

Wait wait wait. So he’s arguing that highly inbred species with high degrees of homozygosity, like many lab animals, are going to have a higher “cognition level” than wild and genetically diverse animals? How did he measure “complexity”? He’s claiming a correlation throughout the animal kingdom, did he really measure the genetic diversity of a large number of species and show that small-brained species are a causal consequence of having greater genetic diversity? Alternative hypothesis: the larger your brain, the more specialized in that category you have to be, and the smaller your population size can be, thereby limiting the number of variants that can exist in the population. You aren’t large-brained because your population has limited diversity, and also, because all Shi Huang has done here is a correlational analysis, he can’t claim causality.

He really has a bug up his butt about the out-of-Africa model. I suspect it’s more about not wanting to have African ancestors, and is fundamentally a racist bias.

For completeness’ sake, here are the rest of his claims. I don’t care anymore. He’s a fool.

Our study analyzed genotype/phenotype from more >400,000 people in the UK, calculated multiple measures of GD for each individual, and examined which traits these measures were associated with using linear regression analysis that has controlled for confounding factors.
Among 17 traits examined, only education attainment, a proxy of IQ, has the best association (inverse) with GD. Only brain-expressed genes, but not brain-non-expressed, showed an association. The association of non-syn variants is higher than that of syn or intronic variants.
Low cognition is subject to natural selection, and so the underlying GD must be also rather than being time-related and not subject to natural selection as assumed by the molecular clock and neutral theory. The finding challenges the assumption of the OOA model.

I tried to dig deeper into who this guy is, but was repelled because he seems to be beloved by the scientific racists. For instance, I got a little of his background from the Free Times (FriaTider), a radical right wing newspaper in Sweden.

Shi Huang received his doctorate from the Univ. of California… and then worked… for a couple of decades, including as an associate professor at The Sanford-Burnham Institute. In 2009 he moved back to China and has since been a professor at Central South University in Hunan. Today he has a professorship in genetics, epigenetics and evolution…

Unfortunately, I got there from a horrible racist blog called “subspecieist”, which, I’m sorry to say, I won’t link to because it is so deeply despicable, but I will mention a previous “discovery” by Shi Huang that got them extremely excited.

Geneticist Dr. Shi Huang: Shocking evidence, Africans closer genetically to Chimpanzees than Eurasians

Jesus. What an ignorant crock of shit. No. That makes no sense at all. Both modern Africans and modern Eurasians are equally distantly removed from our chimpanzee ancestors. Shi Huang really desperately wants to argue that he didn’t have any black ancestors, I guess, and he’ll make all kinds of illogical leaps to demonstrate that.

And this crank still gets published by Nature.

Comments

  1. says

    “Africans closer genetically to Chimpanzees than Eurasians” Yes, it is a troubling statement. But, as I read it, it is also ambiguous. Are africans closer to Chimps than eurasians are close to chimps? OR are they saying that africans are closer to chimps than they are to eurasians? Come on people, Language is a tool that must be used precisely!

  2. says

    Also, to twist the ignorant racist rtwingnut comment around: If we evolved from chimps, why are there still chimps as evidenced by the behavior of MT head Greene and Bobobert?

  3. says

    “The San have the highest GD and the lowest cognition/civilization in humans”
    Really? I’d like to see him dropped into the environment the San live in and see how well his GD and cognition enable him to survive. I don’t think his high education would positively correlate with his survival unless of course he went to San kindergarten and they taught him how to survive.

  4. says

    I must admit this article points out something I was (naively?!) unaware of until a couple of years ago: that there are ignorant, insecure, racist scientists! I was brought up to believe that studying science broadened the mind and precluded such stupid, hateful mindsets.

  5. nomadiq says

    At some risk, I will mention that white euro people are not the only ‘race’ of people on earth who see themselves as mono-cultural, generically pure and homogeneous, and see this as something to be proud of. I wonder if belief in the purity of one’s genetic heritage leads one to think that self-evidently makes you smarter, you just need to go find the data.

  6. raven says

    The US is a highly genetically diverse place.
    We have all races and people from all over the world.
    It is 61% White and 39% everything else.

    So how is our educational attainment?
    I’m sure it is high, higher than Africa and probably higher than China.

    I’d say that educational attainment is more correlated with income and opportunity than genetic diversity, just based on cause and effect factors.

  7. raven says

    Overall, mixed breed dogs are smarter than purebred dogs. Mixed dogs scored 463 and purebred dogs scored 417. In our experiment, we wanted to determine if purebred dogs or mixed breed dogs are smarter. We tested twenty-six dogs of all different breeds: thirteen purebreds and thirteen mixed breeds.

    Intelligence of Purebred vs. Mixed Breed Canines https://csef.usc.edu › History › Projects

    It is commonly believed that mixed breed dogs are smarter and healthier than purebreed dogs.

    According to this study, that is indeed the case.

    This is thought to be due to hybrid vigor also known as heterosis, where more genetic diversity has been shown to lead to higher levels of fitness for many or most traits.

    “Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of any biological quality in a hybrid offspring.”

    Heterosis wikipedia
    .
    Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of any biological quality in a hybrid offspring. An offspring is heterotic if its traits are enhanced as a result of mixing the genetic contributions of its parents. These effects can be due to Mendelian or non-Mendelian inheritance.

    Heterosis has been shown to correlate with intelligence in human populations.

    The progeny of first cousin marriages show an IQ drop.

    Cousin marriage can reduce I.Q. a lot | Discover Magazine https://www.discovermagazine.com › mind › cousin-ma…

    Jul 20, 2012 — – The range in depression for first cousin marriages seems to be on the order of 2.5 to 10 IQ points. In other words ~0.15 to ~0.65 standard …

    The available biological data shows that genetic diversity is correlated with higher IQ, when all other variables are controlled for.

  8. Bruce says

    Surely, any Nature-level reviewer would have asked:
    Where is the part of the paper that correlates GD or height versus say nutrition? To what extent is GD or height explained by nutrition? If one determines and removes/corrects for nutrition variation, how much weaker is ant correlation between corrected height and corrected GD? Is any such correlation stronger than random?
    If the paper (obviously) lacks such data or analysis, then I’d say this undergraduate research quarterly project needs to be redone in order to get passing credit for this semester. I expect better from the undergrads of wherever this is.
    And I’m not even a biologist.

  9. silvrhalide says

    Wow. That is one self-hating POC.
    Is there something in the air or water supply? First Fuentes, now this knob.
    Ten bucks says he considers himself white though, same as Fuentes.

  10. wajim says

    Wait, didn’t he just prove Chinese people are intelligent apes with an ignorant bias against, um, other intelligent apes who don’t look like them? Sounds good . . . And I am NOT a geneticist, and yet I get the gist

  11. says

    silvrhalide @11

    “Wow. That is one self-hating POC.”

    Oh, not at all. Anti-black racism is very much a thing in Asia. It doesn’t surprise me to hear this coming from someone who appears to be Han Chinese.

  12. gijoel says

    Gotta love the hidden implication of scientific racism that treating people less intelligent than you like shit is a-ok

  13. raven says

    That this paper is trash and the authors are outright racists is obvious.
    That isn’t a question.
    The question is what in the hell is wrong with Nature’s Journal of Human Genetics.
    This is just shocking non scholarship.
    Racism is a corrosive negative for any society and gets people killed all the time, sometimes by the millions dead.

    They need to show that educational attainment does in fact have a genetic basis.
    You can’t do that by looking at educational attainment in areas with entirely different socio-economic bases.
    As PZ noted, you then have to show that educational attainment levels are due to differences in “cognition”, and define what “cognition” is and how do they measure it.
    They probably mean IQ and we already know much of IQ is environmentally determined so they couldn’t do this even if they tried.

    If you compared modern day First World humans with their recent ancestors a few centuries ago, our recent ancestors would be morons. Educational attainment in the era of serfdom and slavery for the general population was pretty low.
    Spoiler alert. No they weren’t dumber than us, just from a different age and economy.

    Another issue is controlling for variables. There is a vast number of variables between San living in Southern Africa and any First World population.
    In an experiment or experimental data set, the rule is to have only one variable at a time.

    Explanation: If more than one variable is changed in an experiment, scientist cannot attribute the changes or differences in the results to one cause. By looking at and changing one variable at a time, the results can be directly attributed to the independent variable.Oct 16, 2016

    Why do scientists change only one variable in a controlled …https://socratic.org › Biology › Miller–Urey Experiment

  14. microraptor says

    Tabby Lavalamp @13: I was going to bring that up myself. I don’t know why racism against black people is so prevalent in China but it’s very well documented.

  15. silvrhalide says

    @13 Oh, it’s not just anti-black racism that runs rampant in Asia. Plenty of Asians hate other Asians with breathtaking abandon. Look at the way the Japanese view the Ainu, the Vietnamese, the Koreans or the way the Han Chinese view the Nepalese, the Mongols, Uigurs or Tibetans. Hell, the Koreans don’t like anyone who isn’t Korean and not just any Korean either–South Koreans are extremely racist towards North Koreans. The Vietnamese and Laotians both hate the boat people (who are Vietnamese, Laotian and Cambodian people), the Hoa and the Hmong.

    But I will bet you dollars to doughnuts that Shi considers himself white in the same way Fuentes does.

  16. killyosaur says

    Why would you think he would consider himself white? The way different races in East Asia treat each other is really no different than white nativists hating Italians or the Irish, or Polish, or name your European culture that isn’t considered properly “white”. Racism is just rank bullshit that can easily be applied to any group that is considered different enough from the in group to be hated.

    And yes, it’s a common thing in some Latin American countries to consider “high class” individuals “white” regardless of actual skin color, but that doesn’t mean that particular cultural norm is translated to other areas of the world or that it means the same thing as Caucasian in those countries…

  17. silvrhalide says

    @18 Because Shi Huang was very careful to conflate Europe and Asia in opposition to Africa. In Asia, paler skin and more Caucasian features are more socially desirable than darker skin and traditional Asian features. It’s one of the reasons epicanthic fold plastic surgery is so popular in Asia, particularly with media stars, performers, models, etc and one of the reasons that skin lightening creams are very popular (and profitable) as well. I was reading an interview with Steven Yeun, in which he talks about making choices about his career path and one of his options was to to back to South Korea and be a kind of media star, specifically because his thinner, more Caucasian (relatively speaking) features and relatively lighter skin would make him popular in Asian media in general and Korean media in particular.

    Also, Shi Huang’s “AFRICANS CLOSER GENETICALLY TO CHIMPANZEES THAN EURASIANS” kind of says it all.

    And South America isn’t the only continent or culture that conflates whiteness with social status. Plenty of African countries, particularly the ones along the western coast, consider all wealthy people to be white, even people who are clearly not white. And we are not talking about Alicia Keys shades of caramel skin tones; if Lupita Nyong’o went to Ghana, she would be considered white.

  18. says

    I stopped reading early on, so I may have missed something. If you yourself have good “cognition genes,” and other people in your community have them too, then how the fark would the genetic diversity of your country/region/population/whatever change those genetically-determined cognitive abilities of yours? To the extent that “cognition” is determined by genes at all, it’s YOUR genes that determine YOUR cognition, MY genes that determine MINE, and the diversity between your genes and mine simply isn’t a factor for either of us. This whole idea seems like a bad joke to me…

  19. says

    …using linear regression analysis that has controlled for confounding factors.

    Have they really controlled for “confounding factors?” Have they even admitted what those “confounding factors” may be? HOW did they control for them, exactly? Is there any evidence that they’ve “controlled for” any such thing, or do they just assert that they have in order to sound sciencey?

  20. kome says

    Of course it got published in Nature. Entirely too much of the mainstream scientific community has, for over a century now, been looking for any and every excuse to have the scientific authority to declare that black people, by their very essence, are intellectually inferior to non-black people. This stuff skates by with little to no scrutiny because a LOT of scientists are a little too personally invested in ideas of reductionism and essentialism.

  21. John Morales says

    https://www.nature.com/articles/d41586-022-02071-6

    Retractions are increasing, but not enough

    First paragraph:

    When my colleague Adam Marcus, editorial director at Medscape, and I launched the blog Retraction Watch in 2010, we didn’t realize we were riding a wave. At the time, we thought journals were issuing about three retractions per month. But that hadn’t been true for a decade. In 2010, they were averaging about 45 a month. Last year saw nearly 300 a month. Our database of retractions, launched in 2018, is up to nearly 35,000 entries.

    Perhaps, by the nature of Nature, this article will be added to that database. With a little help from PZ.

  22. says

    I wonder if any Chinese propaganda organs are in any way contributing to this divisive fake-science. It would certainly be in China’s interest, as well as Russia’s, to plant this sort of bullshit to keep Americans divided against ourselves.

  23. tacitus says

    @Raging Bee

    I wonder if any Chinese propaganda organs are in any way contributing to this divisive fake-science.

    From scanning his twitter feed, if there is any Chinese government propagandist involvement, it would more likely be in support of his “Out of East Asia” theory which he claims supplants “Out of Africa” as the best explanatory model for human evolution. If it gained enough traction, I’m sure the Chinese government would be more than happy to amplify the theory than China was the true cradle of humanity.

  24. says

    Yeah, I’d heard Chinese propaganda is big on the idea they’re the true classic civilization, drumming up bad scholarship to push their own civilization back before that in Egypt and elsewhere.

  25. redwood says

    @9Raven. Around 45 years ago I was a grad student teaching ESL in San Francisco. One of my students was a really sweet older Japanese man who I struck up a conversation with after a class. He said he was the president of the Japan Dog Breeders Association (or some group like that) and had come to the US to brush up his English. While talking, he mentioned how much trouble pure-bred dogs had with their health. I made an offhand comment that at least they were smart and he shook his head and said they were lower in health and intelligence than mixed-breed dogs. This was fascinating to me and I’ve been interested in comparisons of pure-bred and mixed-bred animals ever since, knowing, of course, that humans are animals as well.

  26. euclide says

    I’m wondering how to explain the genetic diversity in Africa if not for the Out of Africa Model.
    It seems logical that the place were humans were once endemic is the place were we still find the most diverse gene pool, since all other places were colonized by a relative small initial sample of that ancestral gene pool.

  27. Jazzlet says

    The “out of Asia” ie China idea, definitely has a lot of support in China. There are homonid remains found in China that some Chinese professor insists are “the missing link” proving that China is where the rest of us came from. He won’t let anyone else do a detailed study of them so it’s impossible to conclusively refute his claim, although what he has published has raised considerable doubt especially given all the other evidence we have. I don’t have any links, sorry, I’m pretty sure it was a science news story from one of the collators of such.

  28. Louis says

    Whenever I encounter “scientific racists/racism” I have found it faster and more satisfying to just jump to the end. “Okay, so imagine what you’re saying is 100% true, what then?”.

    A lot of them don’t like answering that question because it exposes them a little too much.

    Unfortunately, we also all know examples of people alllllll too happy to answer that question.

    Louis

  29. cedrus says

    From the abstract, they are describing a well-known result – mutations in brain-expressed genes are bad news. Often, there’s not a spectacular Mendelian phenotype, just a slight nudge away from optimal. This is why older parents are more likely to have a child with developmental delays, autism, schizophrenia, etc. Higher “genetic diversity” in older gametes.

    Granted, it’s not my specialty, so I’m not fully qualified to side-eye the novelty. Maybe explicitly showing the impact of mutational burden on educational outcomes in a good-sized data set is interesting enough to get into Nature. But I’m pretty sure I remember smaller-scale versions of this study from a medical genetics course…that I took a decade ago.

    The rest of it, however, reads like an AI trained on science-truther glurge. Fluent nonsense.

    Also, for what it’s worth, UK Biobank is very, very white – around 5% non-European ancestry.

  30. unclefrogy says

    @25
    I could not read past the part where he tried to claim crap about if you have a true hart about “the others” then it is not racism
    the worst racists always think to themselves that they are not racist because the “other races” are inferior it is just a fact.
    sounds like a very easy paper to write just make shit up to fit with your beliefs Way easier then to really try to tease out some “truths” from so many variables and incomplete data and and ill defined ideas
    bigots goin’a bigot
    of course his type of Chinese are the smarter ones it is a well known fact
    I suspect that there are so many crap papers out there has something to do with money and career advancement more then scholarship for it’s own sake (finding out things that are true)

  31. chrislawson says

    raven@9 — “The progeny of first cousin marriages show an IQ drop.”

    Be very, very careful interpreting that study. First cousin marriages are also highly correlated with poverty (with the exception of royals, but I doubt there were many of those in a cohort of Muslim children from Uttar Pradesh).

    Here’s the original abstract: https://pubmed.ncbi.nlm.nih.gov/8240214/

    There we find that (1) the sample size was small (50 in each arm), (2) there was a strong correlation with economic status but the authors did not test this with a multiregression analysis, (3) “the lower variance recorded in the inbred group did not conform to genetic theory”, (4) “data do not always demonstrate a clear trend of linear increase in phenotypic variance with inbreeding in human populations.” In other words, it’s not a very convincing paper and the authors themselves described several critical limitations. And yet Discover magazine reports this almost completely uncritically mentioning only one of caveats in the abstract and that in parentheses.

  32. chrislawson says

    Jazzlet@30–

    When a researcher makes a bold claim based on evidence he refuses to let others examine, that is sufficient refutation for me.

  33. KG says

    We calculated for each individual four different measures of genetic variation such as heterozygosity and number of variants

    What is meant by “number of variants” as a property of an individual?

    Basically, the authors did some correlations on genomic data in a database, and they think they’ve found an inverse association — high genetic diversity in a population is coupled with low educational attainment.

    I’m not seeing, in the abstract (I haven’t yet looked for the paper) where there’s anything at all genetic diversity in populations

  34. littlejohn says

    Wait. A guy with an Asian name does research indicating Asians, not Africans, are the progenitors of modern humans? What are the odds?

  35. imback says

    @25, @33:
    Here is his redefinition of racism (over two tweets, far down that twitter thread, now I need a shower):

    Racism is the phenomenon that some groups of people maliciously and deliberately intend to harm a group of people (and individuals within the group) through policies or implicit means, which are often accompanied by obtaining illegal benefits and harming the interests of victims. The group of victims can be divided based on objective reasons or any unwarranted reasons.

    Of course that is conveniently worded to be deniable in every case as he’ll claim only he knows his intent.

  36. Reginald Selkirk says

    Low cognition is subject to natural selection

    I’ve been around the world. I’ve found that only stupid people are breeding.
    – Harvey Danger

  37. says

    In some regions of China, 40% of the population have mongol descent. Don’t ask a Chinese racist about that because their heads will explode. Oh, and China’s great civilization was curb-stomped by the mongols. To be fair, most were. But what if the real issue he is measuring is mongol supremacy?

  38. Reginald Selkirk says

    UK Biobank
    UK Biobank is a large-scale biomedical database and research resource, containing in-depth genetic and health information from half a million UK participants.

    So it’s only data on UK residents? So factors like education levels could be linked to status in UK society, not strictly genetic potential?

  39. raven says

    @ 34 chrislawson.

    It’s not just one Discovery article.
    There have been many studies on first cousin marriages that show the same thing. Below is another one with 3,203 children.

    First cousin marriage is common.
    Wikipedia: Worldwide, more than 10% of marriages are between first or second cousins.[2]

    What is happening in first cousin marriages is simple genetics, increasing homozygosity of all genes. Which causes, (Wikipedia) Children of first-cousin marriages have an increased risk of autosomal recessive genetic disorders, and this risk is higher in populations that are already highly ethnically similar.[11.

    My point was that genetic diversity is generally considered a positive goal in populations.
    Populations with low genetic diversity are considered populations on the way to extinction e.g. the Cheetah.

    Heterosis BTW, is how we feed 8 billion humans on our planet.
    Most of the corn and rice planted each year is hybrid corn and rice, designed to be heterozygous for many traits.

    Published: 01 March 1977
    Effects of in-breeding on cognitive performance
    JOSEPH BASHI
    Nature volume 266, pages440–442 (1977)Cite this article

    Abstract
    THE few studies1,2 in which the effects of inbreeding on cognitive performance have been examined revealed that offspring of first-cousin marriages had lower IQ scores than offspring of unrelated parents. These studies were, however, performed in societies where the population engaging in such marriages is a small (1%, 6%)2,3 and unrepresentative proportion of the total population. Possible confounding of the effects of inbreeding with the effects of other intelligence-related variables such as socioeconomic status may lead the effects of inbreeding to be overestimated2. Unfortunately statistical control may either over- or under-correct for the correlates of the independent variables, leaving one in doubt about the true effect of inbreeding. I have now examined the effects of inbreeding on cognitive performance in an Arab population with a high rate of consanguinous marriage which minimised the distortions due to non-genetic variables. I show here that offspring of unrelated parents performed better than offspring of first-cousin marriages in intelligence and achievement tests administered at grades 4 and 6. The lowest level of performance and a higher variance were found for offspring of double-cousin marriages. The inbreeding depression found in this study is consistent and cannot be explained by the effects of socioeconomic status. I drew a nationally representative sample of 3,203 children in grades four and six (approximate ages 10 and 12 yr) of the Arab educational system in Israel. This sample constitutes about 10% of the total population in these grades and includes only normal (not retarded) children. Column 1 in Table 1 shows the division of the subjects according to grade level and consanguinity of the parents. A first-cousin marriage is between children of siblings. Children of first cousins have, on average, 1/16 pairs of genes by common descent. Double first cousins are children of siblings married to unrelated siblings. When they marry, their children have, on the average, 2/16 pairs of genes by common descent.

  40. raven says

    @ 34 chrislawson.

    It’s not just one Discovery article.
    There have been many studies on first cousin marriages that show the same thing. Below is another one with 3,203 children.

    First cousin marriage is common.
    Wikipedia: Worldwide, more than 10% of marriages are between first or second cousins.[2]

    What is happening in first cousin marriages is simple genetics, increasing homozygosity of all genes. Which causes, (Wikipedia) Children of first-cousin marriages have an increased risk of autosomal recessive genetic disorders, and this risk is higher in populations that are already highly ethnically similar.[11.

    My point was that genetic diversity is generally considered a positive goal in populations.
    Populations with low genetic diversity are considered populations on the way to extinction e.g. the Cheetah.

    Heterosis BTW, is how we feed 8 billion humans on our planet.
    Most of the corn and rice planted each year is hybrid corn and rice, designed to be heterozygous for many traits.

    Published: 01 March 1977
    Effects of in-breeding on cognitive performance
    JOSEPH BASHI
    Nature volume 266, pages440–442 (1977)Cite this article

    (I can’t post the entire abstract because something is tripping the filter. )

    Abstract
    THE few studies1,2 in which the effects of in-breeding on cognitive performance have been examined revealed that offspring of first-cousin marriages had low-er IQ scores than offspring of unrelated parents

    I drew a nationally representative sample of 3,203 children in grades four and six (approximate ages 10 and 12 yr) of the Arab educational system in Israel.

  41. says

    This reminds me of a Japanese scientist I read about years ago who claimed the Japanese descended from orangutans, unlike the rest of humanity. This of course made the Japanese extra special. I doubt the orangutans would be amused with him.

  42. cedrus says

    @ 36 re: What is meant by “number of variants” as a property of an individual?

    That’s as compared to the reference sequence. For any variant, there will be a common version and a less-common version. You can go through and count the number of times an individual has the less-common variant. You can also go through and count only the variants where the individual has exactly one of the less-common sequence – that’s heterozygosity.

    Presumably, the argument is that populations with lots of available variation tend to generate offspring with high heterozygosity, and this is somehow bad. (This is why enlightened European civilizations chose to breed their royal families together for many generations, to create a race of super-kings guaranteed to be wise, sane, and healthy…that worked out great, no problems at all.) Alas, their own abstract – I haven’t read the rest of the cursed thing either – says that this is generally false. At best, they show an association between rare variants in brain-related genes and negative brain-related outcomes. Yes, rare mutations are usually rare for a reason. They’re selected against. We have known this since I was in science diapers.

    FWIW it’s possible to directly address the question of selection pressure on brain-related rare variants. This paper doesn’t look like it did anything of the kind, but it can be done. UK Biobank is very white, but there are other sources coming online that should have enough power to address this in other populations. Not sure I’d feel like touching that one with the proverbial ten-foot pole, but somebody’s going to, and I’d bet good money that this schmuck won’t like the answer. With respect to his ancestors and mine, they didn’t have to track their turnips for days while traversing an inhospitable desert full of man-eating predators. Peasants in an agricultural society can afford to be a little bit stupid; it’s not that hard to outwit a rice plant. In the Kalahari, you’re smart or you’re dead.

  43. Walter Solomon says

    It’s one of the reasons epicanthic fold plastic surgery is so popular in Asia.

    Perhaps that’s why he expressed ire against the San in particular since they’re the only native group in Africa who have this feature which is common in East Asia. It hits too close to home for him. It’s not hard to imagine the first humans looking like the San either.

  44. KG says

    cedrus@45,
    Thanks – I thought it might be that, but it seemed too obviously absurd. The reference sequence is presumably compiled from some population, taking the commonest alleles from that population, but I doubt whether it’s compiled from a statistically valid sample of the world population. So I would think (I’m not claiming any expertise here) part of what would be measured is the genetic distance of individuals from the population the reference sequence was taken from, while the rest would be mutations in an individual or their recent ancestors, a proportion of which would indeed be deleterious.

  45. cedrus says

    KG@46: You’re correct, that is exactly what is happening. They’re computing the genetic distance to the average Boomer-aged resident of the UK. To give them a bit of credit, if they did stratify by “genetic principal components” (that’s fancy talk for letting the computer figure out what race you are), then that would subtract out the portion of the genetic distance that’s purely due to ancestry, leaving the portion that’s due to recent mutations. But to take that credit right back, I kind of suspect they had to in order to get the result they wanted; otherwise the Jews and the educated immigrants would mess things up. What they really want is a science-based artifact that they can sneak a few sentences of quote-mine gold into, to the effect that “genetic diversity” is bad, secure in the knowledge that racists won’t read the rest and certainly won’t care to notice the sleight of hand.

  46. snarkrates says

    Raven: “The progeny of first cousin marriages show an IQ drop.”

    And Charles II of Spain has entered the chat…er…sort of.

  47. says

    Here’s a possible alternative explanation of the correlation between increased genetic diversity and decreased IQ: lots of genetic diversity in a given population (as in, a country) implies several different ethnic groups; and maybe those groups aren’t all treated equally or fairly by the rulers and the law; so there are likely to be one or more oppressed groups, who don’t get the same educational opportunities as others; so IQ in those groups goes down, and that drags down the overall/average IQ of the whole population. Did these Han-Chinese race-scientists consider that possible causation?

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