Why race as a biological construct matters

By Razib Khan | May 16, 2013 6:29 am

Credit: Characterizing the admixed African ancestry of African Americans

My own inclination has been to not get bogged down in the latest race and IQ controversy because I don’t have that much time, and the core readership here is probably not going to get any new information from me, since this is not an area of hot novel research. But that doesn’t mean the rest of the world isn’t talking, and I think perhaps it might be useful for people if I stepped a bit into this discussion between Andrew Sullivan and Ta-Nehisi Coates specifically. My primary concern is that here we have two literary intellectuals arguing about a complex topic which spans the humanities and the sciences. Ta-Nehisi, as one who studies history, feels confident that he can dismiss the utility of racial population structure categorization because as he says, “no coherent, fixed definition of race actually exists.” I am actually more of a history guy than a math guy, not because I love history more than math, but because I am not very good at math. And I’ve even read books such as The Rise and Fall of the Caucasian Race and The History of White People (as well as biographies of older racial theorists, such as Madison Grant). So I am not entirely ignorant of Ta-Nehisi’s bailiwick, but, I think it would be prudent for the hoarders of old texts to become a touch more familiar with the crisp formalities of the natural sciences.


In his posts on this topic Ta-Nehisi repeatedly points to the real diversity in physical type and ancestry among African Americans, despite acknowledging implicitly the shared preponderant history. But today with genomic methods we have a rather better idea of the distribution of ancestry among African Americans. The above plot is from Characterizing the admixed African ancestry of African Americans, a 2009 paper with 94 Africans of diverse geographic origins, 136 African Americans, and 38 European Americans. They looked at 450,000 genetic variants (SNPs) per person (there are somewhat more than 10 million SNPs in the human genome). Obviously individuals and populations exhibit genetic relationships to each other contingent upon the patterns of the variation of base pairs (A, C, G, and T) across the genomes of individuals, but there’s no reasonable way to comprehend this “by eye” when you’re talking about hundreds of thousands of markers. The authors used two simple methods to infer clustering within the data set.

First, you see a PCA plot. This method is one where the independent dimensions of variation within the data set of the markers are pulled out. They are rank ordered in terms of how much variation they can explain (dimension 1 by convention explains the most, dimension 2 explains the second most, and so forth). Each dimension can be thought of has having a value proportional to its explanatory power. Each individual then has a value position on the dimension, dependent on how that individual relates to the others. When you take multiple dimensions and transpose the data geometrically you quickly see population structure fall out of the data set. Notice above that the first dimension of variation (PC1) separates the Europeans from all the African populations. The second dimension of variation (PC2) separates the hunter-gatherer populations of Africa from the agriculturalists. While the Mandenka are from Senegal, the Yoruba are from Nigeria, at opposite ends of what is traditionally termed West Africa. This was the presumed source of most of the African slaves who arrived in the United States. Once these slaves came to the United States some of then had children with white Americans.  It turns out that the average African ancestral contribution to to African Americans is ~80%, with the balance being mostly European (there is some Native American, but not much). In fact this is very close to the estimates which were produced by genealogists. The concordance of these methods is reassuring, since the underlying phenomena is the same.

Notice that on the PCA plot no African American falls in the Mandenka-Yoruba cluster. That is because almost no African American whose ancestors are not recent immigrants from Africa lack white ancestry. This is entirely reasonable when you consider that the vast majority of their ancestors were resident in the colonies before the Revolutionary War. Admixture events would have percolated throughout the genealogical tree in subsequent generations. The African Americans are distributed almost perfectly along a line between the West African populations and the European Americans. Observe that the density seems to decrease as you approach the European American cluster.

Now we can move to the second visualization technique. While the PCA does not posit any hypothesis of population structure (it just “fell out” of the genetic variation due to the shared history of some individuals via their common ancestors), the second method is “model based,” in that the authors posited seven ancestral populations to match the seven populations which African Americans may be derived from. In a way this is rigging the game; if you force the method to squeeze out particular numbers of populations it may act strangely. But in this case we have prior expectations, so this number of populations is not unreasonable. Above each bar plot represents an African American individual, with each fraction of shading an ancestral element. The results from the PCA are reproduced nearly perfectly by this differing method. The average ancestral quantum of African heritage in this sample is ~80%. And, you see more cleanly the variation in European ancestry among African Americans. Less than 10% of African Americans are like Barack Obama, at least 50% (or more) of European ancestry. The African ancestry excludes the hunter-gatherer populations which is reasonable since the slaves were from the Congo in the east (where some were Bantu) as far as Senegal in the west.

The first black head of the NAACP

Ta-Nehisi has used an imagine of Walter White, the first African American head of the NAACP, to illustrate the pliability of the black identity. It certainly shows that there are no fixed definitions of race which are particularly useful. But that is a misconception of biological science, which is rife with exceptions and boundary conditions, and characterized by an instrumental perspective. The data above suggests that self-identified African Americans are characterized by some African ancestry, but over 90% are more than 50% African in ancestry. Walter White, who had five black great great great grandparents and 27 white ones, was almost certainly less than 20% African in ancestry. There are such people even today, but they are not typical, and do not disprove the reality that African Americans are predominantly of African ancestry.

From a scientific perspective in biology there are not ultimate and fundamental taxonomic facts. There are simply useful ideas and concepts to illustrate and explore the objective phenomena of the natural world. The Species Concepts debate shows us this reality well, as even species can be tendentious. But the debate often shakes out along disciplinary lines. Many more ecological scientists seem to be taken by the ecological species concept, while evolutionary geneticists are more keen on the biological species concept. That is because they are choosing the framework most useful for their ends. There is nothing “Post Modern” in this in that it denies reality. Rather, we are disputing the ideas which we use to capture the essence of real phenomena in compact semantic relations suitable for symbolic representation (whether with math or language).

Prior to the modern systematic era of biology humans did attempt to classify themselves. Generally they looked at a few informative features. For example the Chinese referred to both South and Southeast Asians as “black,” not because they thought they were African, but because they had brown or dark brown skins. Similarly, Arab ethnographers differentiated between ruddy peoples to the north, black ones to the south, and black ones to the east (Indians). And so on. This is almost certainly an elaboration of our innate cognitive ‘folk biology.’ By this, I mean that we as humans tend to classify organisms. Why this is adaptive is trivially obvious. When humans meet new organisms which resemble those which they have familiarity with prior, they simply reformulate the novel creatures as variants of the familiar ones. For example the Tasmanian Tiger was no tiger. It was not even a placental mammal. But through convergent evolution it resembled placental carnivores. Analogously, when Europeans first met the straight haired brown skinned native peoples of the New World they termed them “Indians,” a straight haired brown skinned population of the Old World. When they met the very dark and kinky haired peoples of the western Pacific they assumed they were some relation to Africans, and these became “Melanesians” (which means “black islanders”).

A second component of human nature which Coates alludes to is our tendency to cohere into groups with narratives of internal identity set apart from the Other. In the pre-modern world these inter-group cleavages would be marked by accent, dress, and tattoos. In the early modern world they would be correlated with religion or nationality. The dynamic at issue here is that extremely genetically close populations which would be indistinguishable naked had to generate salient cultural markers. In the case of the ancient Hebrews one could argue that circumcision was exactly the sort of marker which would persist even when naked!* This does not mean that there were no detectable genetic differences between adjacent small scale societies; there are after all detectable genetic differences across European villages today. But for particular technical evolutionary reasons (far more within group variance than between group variance in regards to genetics) it is likely that for inter-group competition cultural forces reigned supreme over biology, and were determinative of identity.

Both of these parameters are from our deep history as a species characterized by life as hunter-gatherers in bands. The next force is more recent, and historically contingent. As I suggested above non-European and pre-modern peoples had a vague conception of race on the continental scale. The Classical Greeks even distinguished he various brown peoples, the Egyptians and the Indians of the north, and black peoples, the Ethiopians and the Indians of the south. The fact that the initial explorers who arrived in the New World labeled the indigenous people Indians, and not Chinese or Africans, shows an awareness of global diversity (in contrast, the British referred to the Australian Aboriginals as blacks). When the British first arrived in India as supplicants to the Great Mughal they differentiated between the diverse races of the subcontinent. The black and brown natives, and a portion of the elites who were white (West Asian Persians and Turks).

This changed over the centuries, and after 1800 the age of European supremacy and the rise of systematic science produced the sort of racial nationalism which serves as the backdrop to our understanding of race more generally. Whereas the pre-modern folk biological taxonomies were coarse, but generally accurate up to a point, the age of white supremacy produced a somewhat schizophrenic science of precision and exaggeration. By this, I mean that the attempt to be formally scientific resulted in a plethora of categorizations and grades of hierarchy. But, the reality of white supremacy generated a taxonomy of dominion, where all the races of color were aggregated into an amorphous whole. Perhaps these two countervailing tendencies explains the juxtaposition of quasi-fixed racial characters with a bizarrely elastic definition of the Other, the non-white. Few moderns agree with Lothrop Stoddard’s The Rising Tide of Color Against White World-Supremacy, but many implicitly accept the framework of whites and a coalition of “people of color.”

So there you have it. An underlying biological reality which is a reflection of deep history. It may not be real or factual, but it is consistent and coherent. Then there are innate faculties which lead us toward categorization of humans into various kinds, for deeply adaptive purposes. Finally, there are historically contingent events which warp our perception of categories so as to fit into power relations in a straightforward sense. But wait, there’s more!

Diabetes risk higher in African Americans with more African ancestry, link

The biological aspect above focused on ancestry and history. But this is not academic detail. The history of a population affects it genome, and its genome effects the nature of its traits and diseases.  Because of differences across populations statistical geneticists with medical aims routinely restrict their data set to individuals of one population. And, within groups like African Americans which are admixed there is variation in disease risk by genomic fraction. Though an individual with 60 percent African ancestry may feel and say they are no more or no less African American than someone who is 80 percent African in ancestry, there are differences in disease susceptibilities.

There is no Platonic sense where there are perfect categories with ideal uses. Rather, we muddle on, making usage of heuristics and frameworks which are serviceable for the moment. We lose our way when we ignore the multi-textured nature of the issues.

* Though many of the neighboring peoples practiced circumcision, so this is more of an apocryphal illustration than a real instance of functional traits on a cultural level in societies.

CATEGORIZED UNDER: Genetics, Genomics
MORE ABOUT: Race
  • toto

    Am I roughly correct in summarizing your post as follows:

    “Even though ‘races’ have a significant cultural and arbitrary component, they also have a real, biological underlying component, that is strong enough to permit inferences about things that do matter in the real world”

    • razibkhan

      probably.

  • chris_T_T

    The classical definition and conception of the word ‘race’ is too entrenched and changing it hardly seems a battle worth fighting (and likely futile anyway). Best to adopt a different term entirely.

  • marcel proust

    Thank you for this. I find it clear and informative and the opposite of tendentious.

    in re: Walter White, several (very) minor details that have no bearing whatsoever on the point of this post.

    (a) I assume you meant that he had 5 black great great great grandparents and 27 white ones.

    (b) To be absolutely clear about your meaning: by black I think you mean 5 who had no non-African ancestry that dated to the time since they or their ancestors arrived in the New World from Africa; and by white, 27 who had no non-European ancestry that dated to the time since they or their ancestors arrived in the New World from Europe. I’m being picky here because I don’t think that the words “black” and “white” are sufficiently precise to accurately convey the information that I think you are trying to convey.

    (c) Am I correct that you chose that particular generation (g-g-g grandparents) because it is the most recent one with such clear lines of descent.

    • razibkhan

      by black I think you mean 5 who had no non-African ancestry that dated to the time since they or their ancestors arrived in the New World from Africa

      they might have had white ancestors too i think. so that’s why i said less than 20%. these were people who would be socially identified as black is all.

  • TheBrett

    Good essay. I tend to think of it as a reminder that we need to separate “race” from “ancestry”, in the same way that we often separate “gender” from “sex”.

    • razibkhan

      officially we do on the census, but people routinely conflate this. see: “white hispanic.”

  • http://www.facebook.com/karl.zimmerman Karl Zimmerman

    I find the chart shown fascinating, as it shows the lingering social effects of the color line.

    Two of the “white” individuals clearly have some West African admixture. Several of the “black” ones are clearly more than 50% European in ancestry – with two of them apparently only around 25% West African. Was this luck of the draw, or are they “blacks” who had one white parent?

    But there is no one in the intermediate range – people with say around 10%-20% West African ancestry, even though such people are very common in other parts of the world, like Latin America and portions of the Middle East.

    The reason for so few is because of how the color line opened up two options. Many could pass for white (indeed, if someone can “pass” for white, they are, genetically speaking), and thus their African ancestry became diluted within the white genepool. After 1-2 generations, it would be like the two outlier “whites,” and essentially undetectable past this point. If they made the choice not to pass, they would almost certainly need to partner with someone with more black ancestry than themselves, else severely limit their mating pool. If I would hazard a guess, I’d say more men choose to pass (passing generally requires cutting off contact with family, and moving to a new city, after all), and most women married back (as lighter skin for women is considered attractive in the African-American community). This could possibly eventually be studied if “micro-lineages” of mitochondria and YDNA are discovered.

    • razibkhan

      hadn’t thought of that. interesting observation.

    • Jacob M

      Interesting post. I am a white male from the United States. Both my parents are white, and that’s how I’ve always been raised. I recently got my genome analyzed by 23andme and found that my DNA is ~3.5% african. DIY Dodecad gives some estimates up to 5% african. This is mostly from my mother’s side, but also a small part from my father’s side. I am assuming this because my X chromosome has a significant run of African heritage.

      She had always maintained that her family was part Native American, but this did not show up in the analysis. I’m assuming someone in her family was mixed between black/white and made up the story that their appearance was due to Native American mixture, not African mixture.

  • razibkhan

    Funny how the people who tell you that the term ‘race’ has no biological reality are the same who are in favor of affirmative action programs based on…. race.

    they’d say that it’s a social construct with real consequences. it seems a straightforward explanation. i oppose affirmative action in general, but your argument is rather weak if you don’t agree with your normative proposition.

  • razibkhan

    genetic profiles encoded into an elaborate forehead tattoo

    i put my genotype into the public domain, so i probably wouldn’t oppose that if it was not coercive/mandatory.

  • https://delicious.com/robertford Robert Ford

    I was thinking how funny it is those same people are so incredibly interested in what breed a person’s dog is when they see it walking by.

  • Riordan

    Thank you thank you for this piece. The whole Richwine debate needed a good introductory primer for the none numerate, and this one more than serves that purpose.

  • “Progress” Sucks

    No,no,no. People who make the argument that,based on hundreds of years of science proving that race is real and biological,research that wasn’t even disputed or controversial ten years ago until the racial version of Intelligent Designers (that’s you ;)) showed up,race is both real and biological make no prescriptive recommendation at all. And certainly not the kind of authoritarian,tyrannical, top-down force-based prescriptions your delusional kind demand.

    The Catholic Church wasn’t too happy about the scientific research refuting their model of the solar system,either, but how many people have the correct version tattooed on their foreheads today?

    I mean,if you weren’t such a stooge for authoritarianism and a drama queen, you’d be able to conceive of people who just want to know the truth about race and want it to be common knowledge,just like Galileo and others only wanted mankind to know the truth about his place in the universe.

    Knowledge is your friend. Why are you so scared of your friend?

  • http://www.facebook.com/people/Peter-Rosa/1593565364 Peter Rosa

    Reading about Walter White reminded me that the current NAACP leader, Benjamin Jealous, has even less African ancestry. If physical appearance is any guide, Jealous is certainly less than 10% black, quite possibly under 5%.

    • http://www.facebook.com/karl.zimmerman Karl Zimmerman

      I disagree. Walter White, from all the pictures I’ve seen of him, had essentially no visible African ancestry. Ben Jealous visibly has some (e.g., his hair texture and color), although if you didn’t know you might assume he was middle eastern or Latino, so he could “pass” with equal ease.

      His father is white. His mother is a fairly light-skinned but would not “pass” within the U.S. context…probably slightly less than half SSA. If I would guess, Ben Jealous is around 15% or so SSA.

      G.K. Butterfield on the other hand….

  • ESRogs

    Wow, total non sequitur from what was actually said.

  • CraiginKC

    This was a very nuanced and interesting essay, but the one area that I think remains problematic is the slippage between the term “race” as it has been used in cultures for some time, and the term “race” as you’re applying it to genetic data (which we could only access in recent history). I have yet to meet a social constructionist on the question of race that denies that, within particular social groupings there will be a higher rate of shared genetic material. The point behind the Walter White photo is to illustrate that, had White chosen to self identify differently, he would have been taken by the broader culture as “white.” And since the reason these cultural categories evolved as they did in the first place (and the reason why they have evolved differently in other cultures fitting other circumstances) was to differentiate lines of power and privilege, then the fact that Walter White might have a higher genetic predisposition to, say, sickel cell anemia than, say, Teddy Roosevelt, does nothing to illuminate questions of access to power and priviledge (the sorts of things which concern social scientists and humanists). You’ve identified the parallel but distinct discursive systems brilliantly, but after making clear that “race” can mean different things in each discursive system, you seem to revert back to a “one-size-fits-all” usage of “race” when you say: “Though an individual with 60 percent African ancestry may feel and say they are no more or no less African American than someone who is 80 percent African in ancestry, there are differences in disease susceptibilities.” Disease susceptibility was never a primary consideration in the construction of the “African American,” or “Black,” or “Negro.” Those terms grew out of efforts to limit access to power and privilege in our society, and efforts to break down barriers to power and privilege in our society. One’s “African American-ness” (if you’ll pardon the term), is contingent upon their relationship to these questions of power and their identification with others on the same side of the power equation. By equating greater disease susciptibility with greater “African-American-ness,” you seem to be imposing a genetic imagining of “race” onto a cultural category that evolved without the slightest reference to disease susceptibility, thereby being guilty of anachronistic thinking.
    While a day may come when our DNA becomes the primary marker for what divides our world, it’s not the case today. Other markers prevail–markers that certainly reflect visibly inherited physical characteristics, but are not limited exclusively to those visibile traits (as Walter White’s picture would suggest). But thanks for an otherwise well developed argument.

    • razibkhan

      I have yet to meet a social constructionist on the question of race that denies that, within particular social groupings there will be a higher rate of shared genetic material.

      i have. plenty. do you talk to people about population genetics a lot?

      was to differentiate lines of power and privilege

      i disagree radically with your narrative on this, and don’t want to argue about this. the history to me is pretty clear that racial categories pre-edate their co-option into developing power structures. if i disagree with your premise and live in an alternative historical universe then you can see the root of some of the divergences from your understanding. the categories black and white date back to antiquity based on common phenotypic assessments. their character in the sense you allude to is a function of new world slave societies.

      you seem to revert back to a “one-size-fits-all” usage of “race” when you say:

      just to be clear: social constructionists try to impose their own view of race on medical geneticists, and this causes problems. to give a concrete example, the census term “asian” has been used for medical studies, and the south asian samples are obviously totally confounding. a common sense genetic understanding would clear that up, but my understanding is that the forms use census terms for race. in regards to genetics and race there is a lot of talk about how terms like ‘african american’ are not informative for genetics and medicine. this means that one has to outline how racial ancestry can be informative and useful in medical genetics.

      if you’ve read my blog for a while you would have known that this is a long running problem/discussion. if not, you wouldn’t. but that’s the context.

      • CraiginKC

        So let’s go with your premise that the word “black” (or more precisely, some equivalent in a language of antiquity) has been applied to a racial category since antiquity. Surely you concede that the categorization was never static, and never applicable in the same expansive degree that, say, the American “one-drop-rule” iteration of the term utilized it? Who get’s called “black” in America is not the same as who gets called “black” in Brazil, and was probably not the same as who got called “black” by an ancient Greek historian.
        The fact is that you’re utilizing the word race in the year 2013. You’re utilizing categories like “African American” in the year 2013. So any narrative you wish to present about race happens in this context in this time. And when you draw an equivalency between a category based on genetic disease proclivities and link it to a socially constructed category like “African American” as if the touchstone of African American-ness is grounded in these disease procivities so that one is “more” or “less” “African American” based on genetic roots in colonial era Africa, you’re unnecessarily (and problematically) conflating very different constructs: And that was actually the point of your otherwise excellent essay…that these different constructs of “race” are at play. All I’m pointing out is that in the sentence I identified, you engaged in an act of rhetorical slippage.

        I’m certainly not saying that categorization is a brand new phenomenon (okay, maybe you know some clown who is saying that, but nobody I know in academic circles in the humanities and social scientists). But those categories aren’t static in history. You know that.

        Though if we’re going to try and assert the scientific, biological “reality” of race, I’m not sure why we don’t identify races according to genes that determine prostate cancer risk, or alzheimer’s risk, but we jump onto genes that link people to Taysachs or Sickle Cell. Couldn’t we, as easily, apply our racial cookie cutter to an enormous slew of genetic clusters that distinguish this or that population? Would you have felt as comfortable saying that someone who doesn’t have “celiac” disease (prevalent among Northern Europeans) may feel just as “white” as someone who does, but…?

        • razibkhan

          1) the stupid definitions we use are partly NIH dependent. just how it works. i complain about them, but science is dependent on gov. $ and you need to use gov. definitions (i would, for example, get rid of the utilization of ‘hispanic’ altogether for obvious reasons).

          2) there is a correlation between black across time which isn’t trivial. social constructionism has boundary conditions. that’s often ignored.

          3) I’m not sure why we don’t identify races according to genes that determine prostate cancer risk, or alzheimer’s risk, but we jump onto genes that link people to Taysachs or Sickle Cell.

          the standard intuition is that racial clusters reflect population history in genetics. so you take a random number of genes and use those to inform your understanding, not some specific gene which may not be representative. genes subject to selection or rare loss of function variants which seem to rise repeatedly across populations due to bottlenecks are not good candidates.

          if race is about identifying tay sachs, you can use tay sachs races. if race is identifying the average sum totality of genealogies of human beings you need to expand the scope of your marker sense. as it happens a few thousand random SNPs is usually sufficient out of 10 million for intercontinental differences (depending on whether you’re doing PCA or model based).

          • CraiginKC

            Of course, “race” as it has been used commonly in the United States for the past couple hundred years has been neither about identifying tay sachs nor about identifying the average sub totality of genalogies of human beings. It’s been about power and privilege (whether that reality is appealing or not), and as such, the scientific discourse surrounding it has not been immune to those interests, as much as one might like to separate the two. I work under the premise that no knowledge is disinterested knowledge. And once we get beyond the question of what a doctor might test a patient for in terms of illness proclivities, I’m not sure what else can be derived from the genetic questions that would have any utility in how we negotiate our lives in this world. Thanks for the discussion.

        • Anthony_A

          “as if the touchstone of African American-ness is grounded in these disease procivities”

          Given that the main reason that African slaves were imported into the Americas was that both Europeans and Native Americans were far more susceptible to malaria than were Africans, “African-American-ness” *is* grounded in disease proclivities.

          • CraiginKC

            Anthony, I’d appreciate a single citation of a single historian who would has argued that “the main reason” African slaves were imported to the Americas was their lower susceptibility to malaria. African slaves were used very early on in the process of colonization, and their use spiked considerably as the indigenous populations of the Americas were being wiped out by exposure to brutal working conditions, disease, and violence. But I’d sure be interested in an actual historical argument that contends that malarial immunity was “the main reason” for African slave importation.

          • Anthony_A

            1493, by Charles Mann. Don’t have the book handy to look up which chapter(s) this was discussed in, but it’s more than just a page or two.

          • Jacob M

            The idea in Charles Mann’s book isn’t that Europeans decided to import African slaves because of their resistance to malaria.

            Rather that African slaves’ resistance to malaria made the institution of African slavery “work”.

            He points out that the cost of buying and maintaining an African slave may have actually been higher than the cost of having a European indentured servant come over. Further, wouldn’t you prefer having a European servant come over because they’re closer to your culture and could even be directly from England and speak English?

            This system was tried, and did exist, but the fact that Europeans were so susceptible to malaria meant that these individuals never lasted long, whereas African slaves did.

            Further, if you look throughout the Americas, you see a much larger proportion of Afro-descendants in hot humid areas. Look at the Carribean. Look at the coastal areas of Colombia, Ecuador and Peru. Up in the Andes, Afro-descendants are much fewer. In many coastal areas that are prone to malaria, they predominate.

      • http://www.facebook.com/karl.zimmerman Karl Zimmerman

        I actually tend to agree with CraiginKC here.

        I almost posted something about the utility of “black” as a biological race being worthless. I mean, it’s more accurate than it used to be, since non-African dark-skinned groups, like Indians, Melanesians, Negritos, and Aborigines are generally not included.

        But most Sub-Saharan Africans still are. Khoisan peoples are generally not termed “Black Africans” these days. However, Pygmies seem to be classified as such rather more often (perhaps due to their darker skin). East Africans and West Africans are invariably lumped together under the “black African” umbrella as if they are one race, even though they are clearly genetically divergent enough to be two races. All the Sub-Saharan African races are paraphyletic in relation to non-Eurasians, so it we were using modern cladistics (which admittedly doesn’t work within species), it would be an invalid taxon as well.

        It will be hard to train ourselves, but we should speak of a “West African” or “East African” race when talking about biology, not a “black” or even “Sub-Saharan African” one.

        • razibkhan

          East Africans and West Africans are invariably lumped together under the “black African” umbrella as if they are one race, even though they are clearly genetically divergent enough to be two races.

          well, the reality is that the bantu expansion effected such a change that i think it IS valid to lump east + west africans together. despite africans being genetic very diverse, most of that is WITHIN the groups. the genetic distance between nigerians and kenyans don’t have to be rescaled too much. the big gap is between the hunter-gatherer groups and the agriculturalists, and your critique totally is spot on in that situation.

        • Anthony_A

          While the Pygmy and San peoples may be rather genetically distinct from West Africans, they are also a negligible portion of the ancestry of African-Americans. So for discussion about the U.S., it *is* a useful category, as long as one keeps in mind the charts Razib posted.

    • razibkhan

      to be clear, people routinely infer from the fact that most genetic variation is *within* groups rather than *between* groups on a single locus to the consequence that two individuals of the same race are not likely to be more related genetically than either to an individual of the racial outgroup. they don’t necessarily elucidate lewontin’s fallacy correctly, and routinely forget the terms and numerical values, but the inference is consistent and robust.

  • Egyptsteve

    So if the race/IQ debate is to proceed scientifically, then the only IQ studies that can be taken into account are those in which subjects’ race is identified genetically, not by the impression of the IQ tester or the self-report of the testee. Secondly, the proportion of racial affinity has to be taken into account, and again measured scientifically, not guessed at impressionistically. I’d hazard a guess that no such study has yet been done. And therefore, racial IQ claims are pseudoscience.

    • razibkhan

      far too strong an assertion. the imprecision will weak the association, but again, people who self identify african american on average tend to be 80% african in ancestry. and instead of racial IQ claims being ‘pseudoscience,’ one might perhaps say that the claims lack power because they’re using instrumental variables (i.e., u use racial self identification as a proxy for genetic ancestry which you hypothesize predicts a given trait).

      • http://www.facebook.com/karl.zimmerman Karl Zimmerman

        There was an interesting aside in one of the recent Cape Verde genetic papers that socio-economic status in Cape Verde was closely associated with skin color, but not actual European ancestry.

        Hence, I guess you could say we have a good data point that race as social construct matters more than race as biological reality…

        …in Cape Verde anyway. ;)

        • razibkhan

          this result is found in other instances. needs more follow up. but this is a controversial topic, so….

        • JL

          The % of African ancestry is negatively correlated with socioeconomic status in African Americans: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0032840 (see Table S2).

          • Emil Kirkegaard

            A decent proxy for what I recommended to be done, thanks.

        • Emil Kirkegaard

          Source? :)

      • Emil Kirkegaard

        Such a lack of power would tend to dilute the correlation, not make it stronger, right? So if we can find strong patterns even with somewhat clouded data (self-identification of race), that’s a very strong reason to believe there is a real phenomenon.

        In any case, it is very possible to do a pretty decisive test of the hereditarian position: Gather a large sample of African Americans, give them a battery of tests, extract the g factor, get a genome sequencing on all of them, see if the g factors correlates with amount of African ancestry.

        It would be a good test, I think. Seem possible to do, even if a bit expensive. One could even use the sample above, or just put some decent IQ tests on 23andme, and pull some data from their databases when there is enough.

        We will know for certain very soon, in my opinion. I don’t think I will be surprised by the findings.

    • http://www.facebook.com/frank.youell.7 Frank Youell

      Egyptsteve,

      You would have a good point except that… Self-identified race and genetically measured race match with astonishing precision. See “Racial groupings match genetic profiles, Stanford study finds”

      “STANFORD, Calif. – Checking a box next to a racial/ethnic category gives several pieces of information about people – the continent where their ancestors were born, the possible color of their skin and perhaps something about their risk of different diseases. But a new study by researchers at the Stanford University School of Medicine finds that the checked box also says something about a person’s genetic background.

      This work comes on the heels of several contradictory studies about the genetic basis of race. Some found that race is a social construct with no genetic basis while others suggested that clear genetic differences exist between people of different races.

      What makes the current study, published in the February issue of the American Journal of Human Genetics, more conclusive is its size. The study is by far the largest, consisting of 3,636 people who all identified themselves as either white, African-American, East Asian or Hispanic. Of these, only five individuals had DNA that matched an ethnic group different than the box they checked at the beginning of the study. That’s an error rate of 0.14 percent.”

      Interestingly enough their were more mismatches (between the computer and self-identification) over sex than race.

    • hypnosifl

      “I’d hazard a guess that no such study has yet been done. And therefore, racial IQ claims are pseudoscience.”

      I would say the primary problem with racial IQ claims is that it is very hard to separate out the effects of culture from those of biology–you can try to control for some specific culture differences like socioeconomic status, but that’s not really enough. While there is obviously no uniform “white culture” or “black culture” or “asian culture” in the U.S., there are all sorts of cultural variables which would at least vary statistically between broad “racial groups”, and which might have important effects on IQ (attitudes towards reading as a pastime would be an obvious one, along with what types of books tend to be favored as reading material). Even studies of children adopted by parents of another racial group can’t necessarily do a good job of controlling for cultural influences, both because of the role of outside expectations and stereotypes, and also the natural human tendency to form an identity based in part on how others see us, and emulate role models that tie into that sense of identity. Until we can find collections of genes that are strongly correlated to IQ scores and which vary by race, and show that they remain strongly correlated with IQ even when we are looking at variation within an ethnically and culturally homogeneous population, I think any strong claims for or against the idea of racial differences in IQ having a biological component are highly suspect.

  • josh316

    That is no contradiction. If group A has been collectively wronged (regardless of said group’s existence in biology) , then one could argue that they need be collectively restituted .

  • JohnCabel

    A lot of goofy fudging by many people in these posts reminds me of Christian and Mormon apologists playing word games. We can clearly identify “races” by forensic evidence: bones, dental records. Are there no “dog breeds” just “dogs”?

  • http://twitter.com/reiver Charles

    Regarding:

    “Now we can move to the second visualization technique. While the PCA
    does not posit any hypothesis of population structure (it just “fell
    out” of the genetic variation due to the shared history of some
    individuals via their common ancestors), the second method is “model
    based,” in that the authors posited seven ancestral populations to match
    the seven populations which African Americans may be derived from.”

    I know you did not explicitly say this (so I’m not trying to put words into your mouth). This is just a kind of side note (and something you probably already know)….

    Using a PCA is not a model-less approach. It assumes a linear (or near linear) model.

    Perhaps the data really is linear or near-linear is reality, but you could run non-linear analyses on the data.

  • mischling3rd

    What really was the difference between Walter White and this Confederate General with a taint of “black” ancestry? Both were culturally white. Their differences were political.

    http://cwmemory.com/2011/03/17/a-black-confederate-general-that-we-can-all-embrace/

  • mischling3rd

    Walter White looks like a fool. Here’s a real black guy that the government classifies as white. Why? Because he is from Egypt and all people from North Africa and the Middle East have the “honor” of being classified as “white.”

    http://newsfeed.time.com/2012/09/07/egyptian-immigrant-wants-to-be-reclassified-as-black/

  • Emil Kirkegaard

    No. Studies show that self-identified groups match genetically almost perfectly.

  • Kevin Bonham

    I think John’s point is that if race were *merely* a social construct, it would be impossible to determine any differences in bones. The fact that it is possible to discern differences at all implies that there are some biological differences between the two populations.

    • Philosophico

      Yeah, that may have been his point, but if so, it’s not a very good one. Social constructionists don’t deny that there are biological differences between groups of humans, they just deny that there’s anything particularly important or interesting about the particular biological features we use to separate people into races.

      Consider: if there was a society that considered people with Morton’s Toe to be a separate race, their forensic scientists would probably be quite good at identifying members of that “race” based on their remains. The constructionist’s point is that just as this practice seems bizarre and arbitrary to us (though it would surely seem perfectly natural and obvious to the members of that society), so would our practices of racial categorization seem bizarre and arbitrary to an alien observer.

      I’m not actually claiming here that races *are* socially constructed, BTW, and there may be a way to salvage the idea that forensics vindicates the notion of race. But John seemed to think that the *mere fact* that forensic scientists can match people to racial categories entails that races are biologically real, and I’m simply pointing out that one would need to say a good deal more than this to establish the point.

      • razibkhan

        they just deny that there’s anything particularly important or interesting about the particular biological features we use to separate people into races.

        this is a genetics blog. so i don’t focus on characters, though that can be useful. rather, i focus random sets of SNPs.

        • Philosophico

          That’s fine. Again, I was just responding to the claim that the ability of forensic scientists to match people to racial categories is sufficient to establish that races are not socially constructed.

      • Kevin Bonham

        But John seemed to think that the *mere fact* that forensic scientists can match people to racial categories entails that races are biologically real

        I think that it *does* establish this. Getting to your analogy, regardless of how arbitrary outside observers would find it, if Morton’s Toe was an identifying feature people used to delineate a separate race, then it would indeed have a biological basis. If Morton’s Race could then be correlated with other factors, then it could be a useful category.

        One of Razib’s main points here (at least as I read it) is that *all* categories are in some sense arbitrary, but those categories are useful if they provide a framework for addressing interesting questions. An advanced alien might find the distinction between chimps and humans to be arbitrary as well – a cyborg race might see the distinction between animal and plant arbitrary, since they’re both biological.

        they just deny that there’s anything particularly important or interesting about the particular biological features we use to separate people into races

        If we can identify differences in bone structure, then that’s at least one thing that’s interesting about the biological features we use to separate people into races, namely bone structure.

        • Philosophico

          Apologies in advance for the long comment, but things are getting very muddled here and I’m doing my best to sort things out. My hope is that anyone stumbling across this conversation will come away with a better sense of the dialectic vis-a-vis race and forensic science.

          *all* categories are in some sense arbitrary

          Granted, but “in some sense arbitrary” doesn’t mean “anything goes.” Perhaps all racial categories are arbitrary (in some sense), but that doesn’t mean all arbitrary categories (even those with a “biological basis”–a very low bar) are races.

          if Morton’s Toe was an identifying feature people used to delineate a
          separate race, then it would indeed have a biological basis.

          But the question of whether race is a biological (as opposed to social) category isn’t just whether there are differentiating features that “have a biological basis.” If that were all that were required for something to be a race, then we could count “male” and “female” as races, along with “people shorter than 5’6″ ” and “people 5’6″ and taller.”

          The point here is that “race” has to mean more than “group identified by some or other feature that has a biological basis,” since relying on that definition alone would permit an endless proliferation of racial types, some of which (“male/female”) bear no resemblance whatsoever to ordinary or scientific use of the word.

          You’re of course free to use the word “race” however you want, but as your usage moves further and further from ordinary understandings of the word, your claims about race become less and less interesting. To the extent that, according to your definition, “Asians,” “Mortons,” and “Womens” are all equally good candidates for being a race–because hey, bone structure–no one is going to find the generic claim “there are races identifiable by biological features” (JohnCabel’s original claim) to be a very interesting one.

          Now, of course you can go on to say that the features of bone structure that go with being Asian correlate with stuff we care about in a way that having Morton’s Toe doesn’t, and that’s why “Asian” makes for a good racial category. You’re welcome to it, and the proof’s in the pudding. But note that this requires a whole raft of further assumptions beyond the mere fact that forensic scientists can sort people into racial categories that are recognized by the broader society. The probative value of that latter fact alone is zilch.

          • razibkhan

            i’m pretty sure kevin’s assuming a temporal component. relying on one character is technically kosher in some variants of cladistics from what i know. with computers and such these methods are not somewhat outdated, but they’re not wrongheaded necessarily.

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Gene Expression

This blog is about evolution, genetics, genomics and their interstices. Please beware that comments are aggressively moderated. Uncivil or churlish comments will likely get you banned immediately, so make any contribution count!

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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