Of beasts and men

By Razib Khan | September 5, 2011 9:23 pm

“There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare [children] to them, the same [became] mighty men which [were] of old, men of renown.”

- Genesis 6:4

The Pith: Pygmies and Khoisan have admixture from a distinct population at the level of ~2%. This population diverged from the other ~98% of their ancestry ~700,000 years before the present, and the hybridization occurred ~30-40,000 years before the present. Most other African groups have only traces of this element, with some West Africans lacking it.

I have read the paper in PNAS which I referred to below. There isn’t that much I can add at this point. A lot of the guts were pushed into the supplements, which aren’t on the web yet. I was correct that the Mbuti Pygmies of the eastern Congo likely have a special place in this possible admixture event. In particular, they seem to possess the diverged variants found in the western Pygmies, the Biaka, and the Khoisan populations of southern Africa. As assumed the pattern of admixture seems to be such that the two Pygmy groups and the Khoisan exhibit elevated signatures of archaic contributions, while other African groups manifest admixture in direct proportion to their known admixture to the aforementioned populations. For example, the Bantu group with the highest proportion of admixture are the Xhosa, who also have the most Khoisan ancestry of non-Khoisan populations. The West African Mandenka seem to have trivial admixture from this archaic group. What does this mean?


First, let’s stipulate that this is a model which infers the past from the variation we have on hand. In this way it is qualitatively a different method than that used to ascertain the Neandertal or Denisovan admixture events, which derived from comparisons of moderns with the concrete genome of these ancient lineages. The authors in the PNAS paper observe that the likelihood of ever replicating the non-African results within Africa is low because of the nature of fossil preservation. The likely region of admixture, central Africa, is simply not conducive to the preservation of fossils, let alone genetic material. Now, I have stated before that I am cautious of results from computational models because they regularly reported no admixture as well, further confirming “Out of Africa” with 100% replacement. The change here is that our expectations have been shifted by the possibility of admixture outside of Africa. By testing the power of their models on the Eurasian findings they firmed up their credibility in the absence of ancient DNA. These authors used 61 non-coding genomic regions to reach their conclusions. One presumes that these findings should become more compelling once researchers start performing full genome analyses. If not, then they may be spurious.

With that out of the way, let’s review the results and what they mean on the assumption that they’re valid. The PNAS paper supports a model where a subset of descendants of anatomically modern humans (AMH), and an unnamed archaic group, population X, hybridized relatively recently. Within the last ~40,000 years or so. It seems that this post-dates the “Out of Africa” migration. This should not be shocking, and hopefully will dispel the strange notion that Africa remained static after the emergence of AMH (which leads to some reconstructions of early Eurasians as looking like modern Africans!). It also hints at the possibility that contemporary Pygmies and Bushmen are not the ur-humans, the oldest of old, but rather novel morphs which derive from a recent hybridization event (just like non-Africans).

This brings us to why Pygmies and especially Bushmen were assumed to be ur-humans, the best exemplars of early AMH: they’re basal to other human populations,  AMH fossils are found in eastern and southern Africa at a very early date, and they are the most genetically diverse. If this admixture event holds up my intuition tells me that both of these findings are in part derived from this component of the ancestry of these populations. The separation between population X and AMH occured ~700,000 years ago. If I recall my human evolution chronology correctly this is about two hundred thousand years greater than the divergence between AMH and the Neanderthal-Denisovan clade! Depending on the population genetics of the X group, they may significantly reshape a phylogenetic tree which does not incorporate the correct model of divergence and admixture (reticulation).

I assumed that the Mbuti would be special even before seeing the paper because physical anthropologists have long observed that there’s a greater phenotypic difference between them and their Bantu neighbors than the Biaka and their Bantu neighbors. Playing around with public data sets (HGDP) it’s also clear that the Mbuti are more distinctive than the Biaka from other Africans. Additionally, to my great surprise there is a “hunter-gatherer clade,” where the Pygmies and the Khoisan seem to form a cluster against other African populations. It seems implausible to me that these patterns are due purely to admixture from population X. But I think it must play a role. It may also explain the finding from some full genome analyses that West Africans are closer to non-Africans than they are to Pygmies or Khoisan. This may be a function of their lack of population X (and/or, possible back-migration from Eurasia).

At this point I feel a little strange referring to “population X.” It was nice that “X-woman” eventually become the Denisovans. What should we call these potential additions to the human family album? Greg Cochran suggested to me the term ‘Mangani’, by analogy with the use of ‘Hobbit’ for H. floresiensis. Don’t remember who the Mangani were? Here’s Wikipedia on the Mangani:

As described by Burroughs, Mangani are organized in tribal bands ruled by dominant males, or “kings,” which subsist by foraging for fruit, grubs, insects, and sometimes meat, in localized territories. Tribes are generally identified by the names of their kings. Burroughs portrays the Mangani (and indeed most jungle animals) as susceptible to occasional bouts of madness in which they will lash out violently and unpredictably at other living creatures in their vicinity. Tarzan is raised in the tribe of Kerchak, based in the coastal jungle of equatorial Africa, as shown in Tarzan of the Apes and Jungle Tales of Tarzan. As an adult he comes to lead this tribe; later, he becomes accepted in other tribes of Mangani, such as the tribe of Molak in The Beasts of Tarzan. Tarzan continued to associate occasionally with his original tribe until cast out in Tarzan and the Golden Lion, as the result of a Tarzan impersonator having murdered one of its members.

From what I recall in the films and television shows the Mangani are portrayed as rather more bestial, and ape-like, than the description above. It also made the story of Tarzan extremely implausible, more in the vein of Romulus and Remus or Mowgli. But Edgar Rice Burroughs original conception was clearly less fantastic, as the Mangani were intelligent, if profoundly different. If modern humans are the ‘third chimpanzee,’ the Mangani may have been another chimp tribe (H. floresiensis, Neandertals, and Denisovans would also be distinct tribes in this model).

At this point some of you might be alarmed. When evidence for Neandertal admixture surfaced in 2010 message boards had discussion threads with titles such as ‘White People Aren’t Human’. Whether you find this sort of joke amusing or not, it’s at least marginally acceptable to make light of scientific findings to poke fun at what is the dominant ethnic group in the developed world (e.g., see also ‘white people are mutants’). Substitute in black people, and the valence is entirely different. But these findings don’t actually imply this. Many African populations may have the highest quantum of AMH ancestry of all human groups. Rather, this new archaic element is found in Pygmies and Khoisan in particular. The ethnography is rather rich in documenting the dehumanization of these two populations at the hands of their Bantu neighbors. If you have tracked the conflict in the Democratic Republic of Congo you are also probably aware that the Pygmies in particular are targeted in the most grotesque fashion because they are perceived to be less than human. But don’t these results suggest that Pygmies are less than human?

I think on a deep level we may have to start putting this question into the “not even answerable” category. Recently I had an exchange with John Farrell in regards to how Christians, and in particular Catholics, are handling modifications to the “Out of Africa” model. I’m not expert on this obviously, but from what I can gather it seems that some Christian thinkers have taken succor in the romantic narrative of “mitochondrial Eve” and “Y chromosomal Adam” as scientific vindication of at least the general outlines of Genesis. For Roman Catholics, who otherwise can accept evolution without much qualification, the existence of these two individuals is necessary for ensoulment and the fall. Apparently some Catholics are discomfited by the opening toward polygenism implicit in the new model of admixture with archaics.

Since I don’t give much though to the religious implications of science, not being religious, I view the whole discussion with curiosity more than concern. But I think the Christian arguments about the implications of science still have something to teach secular people, because I believe we need to reconceptualize what it means to be human. The “Out of Africa” model, which is classical monogenesis on steroids, does not perturb our intuitions about ideal types and kinds. Rather, it reinforces a Platonic model of what it means to be human, as humans are all kith and kin, descendants in totality and universally from a small group of Africans who flourished ~100,000 years ago. This idea is so pervasive that it even pops up in the series finales of science fiction shows. I now believe that those of us without religious presuppositions should abandon more vigorously this model of humanity.* In a deep sense we already do, in that many of us accept without much controversy that we’re simply the product of material processes. There is nothing which makes us ineffably human. This is why many of us do not consider abortion the murder of a person. At some point the fetus becomes human in all the ways we understand to be human. The zygote’s putative descent from two individuals created in the image of God is not sufficient for us to grant it status as a person. We don’t accept the reality of this descent in the first place.

I don’t think we should be too terrified of this leap. Many of us have already abandoned a deep belief in the idea of ‘free will,’ religious and secular, and yet life goes on. For all practical purposes of decency all human populations present today are basically equivalent as humans. Whatever results we may uncover via science aren’t going to change that, because our intuitions about right or wrong don’t derive from our understanding of the latest science.


Tansey Coetzee

But let’s end on a fun note, because science is fun. To the left is an image of Miss South Africa 2007, Tansey Coetzee. Ms. Coetzee has an Indian mother, and a father who is Cape Coloured. So let’s assess her ancestry. Her mother is Indian, so she is half-Indian. But what about her father? The genetics seems to indicate that the Afrikaans speaking Coloured population has ancestry from Western Europe, India, the Khoisan, the Bantu, and from Southeast Asia. From the Khoisan there will be a dollop of archaic admixture from this new population X. From the Eurasian ancestors there will be Neandertal. The Southeast Asian ancestry of the Cape Colony generally derives from what is today Indonesia (then a Dutch colony). Therefore it is not impossible that Ms. Coetzee has some Melanesian ancestry, and therefore some Denisovan! Yes, the last is a stretch, but work with me. It seems then that Ms. Coetzee may have fractions of ancestry not only from diverse modern populations, but slivers from all the known “other humans!” Above I appealed to your intuition in simply discarding the model whereby humanity is contingent on pure descent from AMH. Individuals such as Ms. Coetzee, and Desmond Tutu, Nelson Mandela, and most of the readers of this weblog, are a refutation of the Platonic model of a human essence made concrete. I know I’m human despite my Neandertal blood. You know in your heart I’m right, so let us accept the finding of science with as much equanimity as we can muster. Our understanding of the details of the human past does not alter our humanity. Just because God is dead does not mean that everything is permissible.

* I generally hold to the position that artificial general intelligence, if it ever arises, should be given the same due consideration, rights, and respect, as organic intelligence. For all practical purposes, they should be treated as we would treat humans. So this isn’t a big leap for me personally.

Image credit: Jose Rosengurtt

  • http://3lbmonkeybrain.blogspot.com/ Mike Keesey

    Tarzan’s apes are clearly meant to be much less humanlike than “population X” would be. But they do recognize themselves as closer to humans than to gorillas (“bolgani”), because they use the same word for humans as for themselves! (For example, white people are “tarmangani” and black people are “gomangani”.)

    Because of this, I have suggested that we use “mangani” for the human-chimpanzee clade, which otherwise lacks a convenient vernacular term. Further discussion here: http://3lbmonkeybrain.blogspot.com/2009/12/mangani-clade.html

  • http://entitledtoanopinion.wordpress.com TGGP

    John Hawks is inviting folks to participate on an open science initiative involving the possibly preserved skin of an australopithecine. It’s from Johannesburg rather than central Africa, does the environment for preservation there compare to Europe or the Middle East?

  • Miley Cyrax

    “This brings us to why Pygmies and especially Bushmen were assumed to be ur-humans, the best exemplars of early AMH: they’re basal to other human populations, AMH fossils are found in eastern and southern Africa at a very early date, and they are the most genetically diverse. ”

    I’ve never understood why anyone would assume extant basal lineages are any more genetically and/or phenotypically similar to the common ancestor of the greater clade than any of the extant non-basal lineages. This doesn’t just go for humans; in fact, I see it more with non-human taxa.

  • Sandgroper

    As long as the artificial intelligence is housed in a hot looking robot, I’m cool with that.

    There has been some discussion that these past admixture events must have yielded selective advantages for the evidence of them to have survived. (It seems reasonable to presume there were other admixture events of which there remains no evidence now because they did not yield particular selective advantages.) Consequently I don’t see any grounds for anyone to presume that any surviving people are any less modern human than any others.

    In fact, the more evidence that emerges of archaic admixture in different populations, the less grounds I see for anyone taking this kind of view.

  • gcochran

    To be blunt about it, if you judge by evidence, human races differ significantly in their capabilities. Archaic admixture may play a role in explaining that, but whether it does or not, the fact of the differences remains.

    In my mind, that is no reason to mistreat anyone: but then my basic assumptions are very different from yours.
    Christ died for all men.

  • http://www.catholiclab.net Ian

    You say “At some point the fetus becomes human in all the ways we understand to be human.”

    So, what do “we understand to be human”? Is this a corporate “we”, or an individual “we”? Am I part of the “we”? Are you?

    Surely science tells us that a human embryo, human fetus, human infant, human child, human adult is still human regardless of it stage of development.

  • Justin Giancola

    It’s interesting how we can have two people (5&zib) go about the same position with starkly different tacts to arrive at the same conclusion. There’s something, say “Platonic” ;) , about the idea that hatred begets hatred.

  • Bob Dole

    @Ian
    I think we should debate abortion on the internet. I don’t think that’s been done before.

  • John Emerson

    I think that the African attitude toward pyhmies isn’t so much that they’re less than human, but that they’re strange, fundamentally different people with occult powers that can be used for good or evil. People have had similar ideas about gypsies, Lapps, and all sorts of other marginal pariah groups elsewhere. Often the same people who are lynched and burned at the staka are, at other times are called on for their magic.

    American PC looks a lot better once you have had a little contact with some traditional culture where almost everyone without exception believes that some other population is evil by nature and can’t be changed. In East Asia, for example, it’s not hard to find Japanese or Chinese who believe that the other group is evil, and usually they won’t like Koreans either.

    America has been and still is more receptive to foreign immigrants than almost any other nation, even though there’s always been friction and trouble at first.

    Of course, America’s receptiveness to (for example) Arabs and Filipinos and Jews is partly simply the result of the fact that we have our own hierarchy of Others: black, Native American, and Hispanic. (Prejudice against Native Americans has faded away in the general culture, but still is alive in places where they are concentrated, e.g. near Indian reservations.

    Part of the

  • Mark

    What Ian said.

    One thing I don’t get about middle of the road pro-choicers, who are or are close to a plurality in this country, is that they will state that at some point, usually after the first trimester, the fetus becomes a person–but they don’t blanch at the fact that since Roe v. Wade, there have been about 3-4 million late-term abortions (murders, by their definition) in this country, relatively few of which were done for health/medical purposes.

    @Bob Dole – bring it up with Razib, who broached the issue.

  • John Emerson

    The NRLC (anti-abortion group) estimates 18,000 late-term abortions a year, defining “late term” broadly as 19 weeks after conception (others say 24 weeks). That comes to ~700,000 since Roe v. Wade. I don’t know where the 3-4 million number comes from.

    http://www.nrlc.org/news_and_views/Dec10/nv120210part3.html

    It’s OK with me if Razib deletes this post along with the other abortion posts.

  • http://theviewfromhell.blogspot.com Sister Y

    The religious objection to abortion is not about personhood, but about submission to God. If it were about the destruction of persons, religious people would be much more concerned than they are about preventing spontaneous miscarriages, which kill more fetuses than abortion.

  • http://3lbmonkeybrain.blogspot.com/ Mike Keesey

    Had an interesting thought: click consonants are only found in the Khoisan, Hadza, and Sandawe languages, and languages that have borrowed click consonants from those (e.g., Xhosa, a Bantu language, borrowed clicks from Khoisan languages). (Pygmies have lost their original languages, which were replaced by Bantu languages, so it’s unknown whether they had clicks or not.) It’s been hypothesized that click consonants are basal for the human clade, and lost in a major subclade that includes most Africans and all non-Africans. But what if click consonants were inherited from “population X”?

    Just a thought — we’d have to show that Hadza and Sandawe also inherited DNA from “population X”. (Does the study look at them?) Even then it would be far from an open-and-shut case. One troubling difficulty is that, if Pygmies used to have click sounds, why did they lose them upon contact with Bantu peoples, while Khoisan not only kept them but in fact spread them into Bantu languages?

  • pconroy

    @13,

    Xhosa probably has clicks as Bantu farmers married Khoisan women to form the hybrid Xhosa population, and so offspring naturally picked up clicks – so I don’t see that as spreading from Khoisan, rather some Khoisan (women) being assimilated by Bantu farmers.

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    i’m going to close the thread if there is more talk about abortion. and #6, you aren’t part of the we. sorry, but the vast majority here are secular and support abortion rights. that might not be optimal for you, but just how it is. i was talking to them.

  • http://3lbmonkeybrain.blogspot.com/ Mike Keesey

    @14,

    I don’t see the distinction. You just described HOW Khoisan consonants spread into some Bantu languages.

  • ackbark

    Genetics is like music, not one note but a lot of them

    As all these populations do descend from a common ancestor, does that not make the question of humanity moot? It seems more like increasing humanness over time toward, rather than from, a Platonic template.

    Also I think we should drop the term ‘archaic’. When they were around were they any more ‘archaic’ than anyone else?

    But my question is, when did the pygmies become pygmies, before or after the admixture event?

  • Fabio

    So present-day Mankind is a big hybrid swarm resulting from several Homo species having sex with each other. A more interesting Origin than drab Adam and Eve tales. Just muse on how taxonomists should treat us.

  • Ian

    Just to be clear – that Ian (#6) isn’t me. (And, @Razib – why not just delete them? This is far too interesting a topic to close).

    With respect to the loss of click sounds by Pygmy peoples, the fact that they lost their language is probably sufficient to explain the loss of clicks – assuming that they had any to begin with. You can’t transmit linguistic elements that you have lost. Why this happened is another question – but it’s worth noting that Pygmy groups are paired with adjacent villages of farmers in a way that Khoisan groups do not. A model for language loss by Pygmies but not by Khoisan groups based on these specific arrangements does not strike me as far-fetched.

  • pconroy

    @18,

    Right, there might have been many Pygmy languages, and Bantu served as a lingua franca – for trade or exchange purposes – which eventually became their primary language.

  • http://3lbmonkeybrain.blogspot.com/ Mike Keesey

    @14, on further thought, I can see your point. You’re taking a demographic and/or geographic viewpoint (there is a group of people living in a certain area which has continuously used click consonants, even if there has been admixture from invaders), while I suppose I was taking more of a linguistic viewpoint (there is a language family that originally had no click consonants, but now one of its subfamilies does via lateral transfer).

    @18, clicks could still be transmitted even if there were language loss. For example, if all Khoisan languages die out in the next century, the clicks will likely persist in Xhosa and other Bantu languages. But your other point, about the difference between the Bantu-Pygmy and the Bantu-Khoisan relationships, makes sense to me (and maybe helps to explain why Pygmies lost their languages while Khoisan didn’t).

  • Checkmate1

    Forgive the ignorance ( my field is Astronomy, and of no use here), but I wonder if it is possible in a language using clicks to yell, shout, or warn other people at a distance? Is it only a viable language over small distances?
    I wonder if the loss of click sounds is promoted by a change in climate and environment as much as cultural transfer?
    I can imagine one person in a rainforest saying to another, “Let’s go to the other side of the valley, the food is better.” However, “Look out for the lion!” on an open plain, into the wind, to another person 200 yards away seems more difficult. Can it in fact be done?

  • chris y

    Can’t remember who it was but somebody recently proposed “Mangani” for the clade including Homo and Pan but excluding Gorilla. You’ll have to fight it out.

  • http://3lbmonkeybrain.blogspot.com/ Mike Keesey

    @22, click languages still have vowels, so it should be possible. (The clicks are just another type of consonant.) I have wondered if there’s some acoustic property that makes them more useful to hunter-gatherers in an open environment (e.g., San, Hadza, Sandawe), but I have no idea. (But I would think that clicks would usually be *louder* than other consonants.)

    @23, see first comment. (Unless someone else had the same idea.)

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    some of these comments are very not-retarded. nice :-)

  • ackbark

    I’ve wondered if the clicks in click languages were evolved by hunter-gatherers to signal one another while hunting because they better mimic background noises in the forest.

  • pconroy

    @24,

    I’d imagine that Clicks travel over larger distances?

    The native Canarians used a whistling language called Silbo, with which they could “talk” from one mountain to another.

    It’s interesting that one of the San genomes had a non-standard FOXP2 SNP. Which prompted me a year ago to speculate that the standard human FOXP2 introgressed from Neanderthals. But maybe it’s the case that some SAN have an archaic introgressed FOXP2. Or is this mutation confer some advantage in producing clicks?

  • http://3lbmonkeybrain.blogspot.com/ Mike Keesey

    @26, the same thought occurred to me.

    Dunno if it’s relevant, but plenty of people (self included) use click sounds when calling domesticated animals. Perhaps because (as @27 says) they travel further.

    @27, interesting speculation. One thing to do would be to show that native South Africans do indeed have an easier time producing these sounds, controlling for whether an individual’s first language has clicks or not. (Tough experiment to perform, probably.)

  • Justin Giancola

    Is this title a play on Of Mice and Men? I saw the movie as young kid and was really enjoying it, and then it turned and cried my eyes out when they killed the handicapped guy. It blew my mind back then.

  • DK

    Just muse on how taxonomists should treat us.

    Down with human exceptionalism! :-) Chances are that if any wide-ranging species were to be studied as exhaustively as H.sapiens, all kinds of weird things would be found in its evolutionary history. This is life. Life is always complicated. And any taxonomy is always imperfect.

  • M-K

    “But she [Tarzan’s ape foster mother] was still an ape, a huge, fierce, terrible beast of a species closely allied to the gorilla, yet more intelligent; which, with the strength of their cousin, made her kind the most fearsome of those awe-inspiring progenitors of man.”
    –Tarzan of the Apes, Chapter IV

    For what it’s worth, Paul du Chaillu describes at least one “species” of chimp still not recognized by biologists in his 1861 Explorations and Adventures in Equatorial Africa (an interesting read). Burroughs relied on this and other accounts by early explorers for the backgrounds of his first Tarzan novels.

  • DK

    It’s interesting that one of the San genomes had a non-standard FOXP2 SNP.

    I am wondering if this can be a sequencing error? Because if it’s not, it’s huge. For it is not just some non-standard SNP but a full blown missense mutation, a potentially drastic one, too – L558P. That position is in the forkhead DNA binding domain, close to protein-DNA interface, likely to be critical for maintaining local structure. It seems to be absolutely conserved in mammals (I checked: monkeys, elephants, hamsters). All that in a protein that has only three amino acid residue differences between mouse and human and it’s either a sequence error or a mutation that ought to have huge functional consequences.

  • Sandgroper

    In the first episode of the BBC series Razib posted a while back, the presenter notes that a click language is very suitable for hunters to communicate quietly while stalking prey animals. Basically, all sound seems to disappear except the clicks, which are very quiet, and could be indistinguishable from insect sounds. As modern humans evolved as group hunters, this would have high utility.

    For using at distance, shouting warnings, etc, I’d guess the vowels come into play much more.

  • Eurologist

    “I wonder if it is possible in a language using clicks to yell, shout, or warn other people at a distance? Is it only a viable language over small distances?”

    Miriam’s voice disagrees(/d):

    http://www.youtube.com/watch?v=HfZA4TkjbtE

    At any rate, I think vowels are fine, we all raise our vocal range when shouting (especially over noise; while acoustically, lower tones are more appropriate over extreme distances). And I agree that click sounds are a bit more clandestine and have been used in the context of animals (but not as a full-fledged language) elsewhere for millennia. As such, I also highly doubt there are any specific genetic links for sound production: so far, research seems to show that any known language can easily be learned by newborns regardless of genetic background.

  • Mark

    Razib,

    I respect your blog and have no desire to show disrespect by bringing back up a subject whose discussion you’ve proscribed, but I also don’t want people to think I just make up inflammatory numbers. So, as my last comment on this issue and thread if you’ll permit it:

    @Emerson – I got my figure from the Supreme Court’s holding in Gonzales v. Carhart (2007), which relied on figures from Planned Parenthood.

    Again, my last comment here.

  • John Emerson

    No link, Mark. Why did a right to life group use much smaller numbers? I smell a rat.

  • Mark

    John,

    I went back and looked over the comments, and I think the discrepancy arose because we are using “late-term” differently. My comment uses “late-term” to refer to abortions done in the second and third trimester. Yours defines “late-term” to mean abortions done 19 weeks after conception, which is toward the end of the second trimester. If your definition is the commonly accepted one then I apologize for using the term carelessly.

    Gonzales v. Carhart is here: http://www.law.cornell.edu/supct/html/05-380.ZO.html The exact quote is: “Between 85 and 90 percent of the approximately 1.3 million abortions performed each year in the United States take place in the first three months of pregnancy, which is to say in the first trimester.”

  • Bob Dole
  • http://washparkprophet.blogspot.com ohwilleke

    Most people in the world will never meet a Bushman or a Pygmy or a Melanesian. Yet, they have an outsized share of human genetic diversity. The undertold story that is the necessary corollary of that is that the largest subpopulations of Africa and Asia are more closely related than intuition on the overall levels of diversity in those populations would suggest. West Africa, for example, is far more genetically homogeneous than the high level of political and linguistic fragmentation there would suggest, and the European-Asian gap is small indeed. The odds of a Greek man and a man from Northern Ethiopia having significantly overlapping genomes is much higher than most people would expect.

    The psychological importance of the fact that a huge number of populations of the world have archaic admixture is probably greater than the fact that more populations have been discovered to have ancient admixture from different sources. The destructive ideologies of racism are caught up in the notion of purity, and deprived of that have a hard time reaching a boiling point.

  • John Emerson

    Few think that second-trimester abortions are late-stage murder. Your original statement was off in that respect.

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About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com

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