Thursday, March 01, 2012

Do Human Races Exist?

This is a question that's come up many times in the blogosphere. My own answer is "yes," humans races/populations/demes/subspecies do exist.

Human Races Populations
Is Race a Biological Concept?
Genetically Speaking All Races Are Equal
Changing Your Mind: Maybe Human Races Do Exist After All
Matt Nisbet Asks an Embarrassing Question
Genetics and Race
Greg Laden on "Race" (Again)
Anne Wojcicki's Politically Correct View of Race
The Problem of Race .... Again
Human Races

The latest dust-up began with a book review by Jan Sapp in American Scientist [Race Finished].
Science has exposed the myth of race, but as the diverse array of essays in Race and the Genetic Revolution shows, folk conceptions of racial typology are kept alive in various sociopolitical forms, and proponents of various DNA-based technologies continue to use erroneous biological conceptions of race as the rationale for using these technologies. Race is not just a sociocultural construct; it is a technological and commercial artifact that persists today.
Jan is a professor at York University here in Toronto and we have met on several occasions. Usually I agree with his positions on evolution but not this time. He is dead wrong when he says that "science has exposed the myth of race." In fact, science has demonstrated that races exist in humans and in most other species.

Jerry Coyne makes this point in Are there human races?.
I haven’t talked much about Sapp’s review, as I find it tendentious; nor have I read the books he’s reviewing. Perhaps I’ll change my mind about race after reading them, but based on what I know about human population differentiation, for now I think that “races” are biologically real (though we can’t delimit them precisely), and are certainly not “sociocultural constructs.” The "sociological constructs" thing is simply political correctness imposed on biological reality. In view of the morphological and genetic differences among human populations, how can such differences be “constructs”?
Nick Matzke gives the typical, politically correct, response that has evolved over the past decade or so. Originally, the race deniers tried to claim that there were no significant genetic differences between various human populations (skin color being superficial and irrelevant). Once that myth was shattered, they fell back on the position that there are differences if you pick the right groups (e.g. comparing the average native citizen of Lanzhou and Uppsala) but this is unfair. If you look at the edges of these population you will see a smooth, continuous gradation of genetic markers [Continuous geographic structure is real, "discrete races" aren’t]. This is sort of like arguing that there aren't two species of gulls because they form a ring species. You could quibble about whether the Lesser Black-backed Gull and the Herring Gull are different species but if they aren't, then they certainly are races even though the various races can interbreed at the margins.

Nobody says that human races can't interbreed to form hybrids of various types with a mixture of genetic markers. The concept of "discrete races" or "pure races" is a political construct, not a biological one.

Razib Khan supports Coyne's argument that human races exist and they are a reflection of evolutionary history [Jerry Coyne on race: a reflection of evolution]. Coyne has a second post on More on genes and geography: diagnosing your ancestry from your DNA, showing how easy it is to distinguish various human populations based on the frequency of alleles they contain.

Here's a quotation from Theodosius Dobzhansky. It was originally brought to my attention by John Hawks [Dobzhansky on continuing human evolution].
The chief reasons why so many people are loath to admit the genetic variability of socially and culturally significant traits are two. First, human equality is stubbornly confused with identity, and diversity with inequality, as though to be entitled to an equality of opportunity, people would have to be identical twins. Human diversity is not incompatible with equality. Secondly, it is futile to look for one-to-one correspondence between cultural forms and genetic traits. Cultural forms are not determined by genes, but their emergence and maintenance are made possible by the genetically conditioned human diversity
Here's a repeat of the rules I imposed in some previous postings.
Let me sound a note of caution to those who wish to comment. The fact that humans races might be genetically different says absolutely nothing at all about equality and racism. For this thread only, I will delete any comments where the author is confused about this distinction. This is a discussion about science and whether some scientific investigations should be censored because they might be misinterpreted.
My position on this topic is very close to that of Bruce T. Lahn and Lanny Ebenstein as expressed in an opinion piece in Nature (Lahn and Ebenstein, 2009).
The current moral position is a sort of 'biological egalitarianism'. This dominant position emerged in recent decades largely to correct grave historical injustices, including genocide, that were committed with the support of pseudoscientific understandings of group diversity. The racial-hygiene theory promoted by German geneticists Fritz Lenz, Eugene Fischer and others during the Nazi era is one notorious example of such pseudoscience. Biological egalitarianism is the view that no or almost no meaningful genetically based biological differences exist among human groups, with the exception of a few superficial traits such as skin colour3. Proponents of this view seem to hope that, by promoting biological sameness, discrimination against groups or individuals will become groundless.

We believe that this position, although well-intentioned, is illogical and even dangerous, as it implies that if significant group diversity were established, discrimination might thereby be justified. We reject this position. Equality of opportunity and respect for human dignity should be humankind's common aspirations, notwithstanding human differences no matter how big or small. We also think that biological egalitarianism may not remain viable in light of the growing body of empirical data (see box).


[Image Credit: The image is obviously the cover of Scientific American from December 2003. This is one of the most blatant examples of political correctness ever published in a prestigious journal and it's one more example of the decline of Scientific American. It doesn't take much to recognize that the faces on the cover are identical except for skin color. As if that's all there is to human populations.]

Lahn, B.T. and Ebenstein, L. (2009) Let's celebrate human genetic diversity. Nature 461:726-728 [Nature]

44 comments:

  1. Yeah, I read Matzke's post this morning, well I sort of skimmed it. It seems to me that if you are going to use that line of reasoning for why Races don't exist you need to apply that same set of criteria to things like species concepts, especially let's say species concepts of microbial organisms. If you'll say human races don't exist, bacterial species may not exist, and ring species/species gradients of any sort aren't really separate species, separate races, or anything more than some vague geological genetic clustering I'll give you props for being consistent in your definitions. Otherwise you are simply cherry-picking human races as somehow being totally different from all of those other examples of cases where human categorization into discrete bins is only an approximate model of biological reality.

    Because that is what is going on here. Races are real in the sense that they are an approximation to the underlying biological reality. That definitely does not make them a "socio-cultural construct" as Sapp is saying. That is a non-starter and incorrect position from the get go. They are a scientific modelling of continuous data into discrete bins/clusters.

    The fact that you can get non-trivial clusters at all from genetic data shows that the underlying biology is real.

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  2. That there is even a debate on such a transparently trivial question speaks volumes of poor intellectual atmosphere in humanities.

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    1. or it speaks volumes that the message is unclear.

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  3. That gene frequencies vary geopgaphically is one thing. That human beings can be separated into discrete "races" is quite another. If we were to bin human beings based purely on their genome, the pattern of bins we would end up with would depend entirely on the procedure we adopted for weighting different parts of the genome, and the level of fine-grainness we chose. And we certainly would not end up with a set of bins that looked anything like the current assignment of people to races. Hence, race is a social, not a biological concept.

    Also, "political correctness?" The 1980s called, they want their lame whines back.

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  4. temperatures may be plummeting in Hell: I agree with Larry Moran...

    That human beings can be separated into discrete "races" is quite another.

    Look, nobody--NOBODY--is arguing for an old-school typological or "discrete" race concept, OK? Everybody readily acknowledges the fuzzy edges, the lack of one or a few wholly robust phenotypic markers, etc. We're not talking about that.
    Also nobody does, or should, deny that there is a valid sociological concept of culturally-constructed race, and we're not talking about that either.
    The fact is that multivariate clustering of human genetic variation does, at some levels of graininess, correspond damn closely to the geographic continents (as anybody who knows anything about genetics ought to predict)--see Coyne's post for the data.
    You don't have to call it PC if you don't want, but most discourse on human races these days is clearly dominated by ideology rather than biology.

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    1. It just got very cold down here ....

      What happened?

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  5. @JW Mason: Welcome to the problem of categorization/binning/clustering in all of biology. We even have problems with this at the species level, let alone sub-species/races. Sure some groups of organisms (Metazoans) work far better than other. But there really aren't any generalities and when we start talking about defining species at the genomic level we run into similar problems. Which features do we weight more heavily, etc.

    That's the problem you always run into with clustering of biological data. We are taking something continuous/quasi-continuous and trying to place it into discrete bins.

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    1. Except for the metazoans seems like a pretty big exception.

      Anyway, for species, you have the criteria of an interbreeding, reproductively isolated population. For higher taxa you have cladistics. neither of those work for human "races".

      if biology supports a myriad of different ways of grouping human beings, with no basis for the the binning we call "race" , then in what sense is it true that "race is real"?

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    2. nobody--NOBODY--is arguing for an old-school typological or "discrete" race concept, OK?

      No, not OK.

      In common discourse, that is exactly what the word "race" means. If you are talking to e.g. the readership of Scientific American (the audience specified here) and you say "race exists," what you mean is that "race [in the sense that lay Americans use it, i.e. of discrete distinct races] exists." If you want to talk about other distinctions between populations of human beings, quite different from the general meaning of the word race, you should adopt a different word for them.

      I don't mean to get all PC on you (oh no!) but many of the worst atrocities in human history have been justified on the basis of belief in old-school race, which is very, very far from extinct. (Again, it's the way most people still use the concept.) So it really behooves biologists to be careful with there language on this subject.

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  6. Hi Doctor Moran

    So "race" is a synonym of the word "population" as used in genetic, right?

    I have no problem with this definition. But as you probably already know "race" means something significantly different in our societies. For instance the idea of a "black race" is a social reality and also a social construct or if you prefer a historical construct despite the fact that this construct is based on some real biological variations. I’m sure you understand why…

    And so completely I agree with JW Mason.

    So Doctor Moran don’t tell us how many races you identify within Homo sapiens because I'm sure I can define much more.

    Best regards

    PS: Sorry for my poor English.

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  7. Everyone agrees on the science, but not on the meaning of the question. Clearly, a claim that "science has exposed the myth of race" refers to the idea that races can be cleanly delineated, not to the existence of diversity or the possibility of "fuzzy" clustering.

    The claim that races can be cleanly delineated is not politically irrelevant: it was fundamental to several laws in South Africa as recently as twenty years ago (e.g. laws stating that only members of certain races may vote - such laws simply make no sense if one does not accept this claim). Today South Africa still has laws (aimed at redressing past injustice) requiring clean delineation between races, although the delineation is now done via self-identification - i.e. using a social rather than a biological notion of race.

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  8. Larry et al., thanks for the comments/critiques.

    Yeah, I read Matzke's post this morning, well I sort of skimmed it. It seems to me that if you are going to use that line of reasoning for why Races don't exist you need to apply that same set of criteria to things like species concepts, especially let's say species concepts of microbial organisms. If you'll say human races don't exist, bacterial species may not exist, and ring species/species gradients of any sort aren't really separate species, separate races, or anything more than some vague geological genetic clustering I'll give you props for being consistent in your definitions. Otherwise you are simply cherry-picking human races as somehow being totally different from all of those other examples of cases where human categorization into discrete bins is only an approximate model of biological reality.

    Lucky for me, I would agree that bacterial species may not exist, and that most standard species concepts break down with cases like ring "species". ;-) In fact, I would basically agree with Brent Mishler's view (see google scholar) that species are not uniquely real. If they are real, they are clades, and if we want to call the smallest identifiable clades "species" that's fine, but there is nothing particularly special about that "level" of clades. On this definition, many geographically/genetically isolated subspecies would be clades and thus "species", which is also fine, as long as everyone is clear on what definition is being used.

    The problems with endorsing the race concept in humans, though, is that (a) there aren't such clades to identify in humans, at least no one has yet, and (b) no one has come up with another objective definition of race, as evidenced by the fact that neither Jerry Coyne or Larry Moran nor anyone else has been able to come up with an objective definition of "race" that lets us identify who is in which races, and how many races there are, even approximately.

    Other reactions:

    "The fact is that multivariate clustering of human genetic variation does, at some levels of graininess, correspond damn closely to the geographic continents (as anybody who knows anything about genetics ought to predict)--see Coyne's post for the data."

    As I noted in my post, you could literally just throw a bunch of points on a globe in a grid pattern, exclude those that fall in water, measure the geographic distances between the points, and get this sort of "clustering". If genetic distance between humans is mostly smooth and continuous (in pre-1500s populations) and correlated with geographic distance, a clustering of genetic distances would produce the same pattern as the geographic distances clustering -- *even though there are no clusters in the genetics, just the spatial relationship of the points*. And the inference that clusters are real is even worse if your sampling is not gridded but instead the sampling is clustered sampling, for reasons of convenience or funding or political permission or whatever. It is theoretically possible there is some true discrete clustering signal in human genetics, but the mere results of standard clustering algorithms are not evidence of it. I would like to see an explicit test.

    "That's the problem you always run into with clustering of biological data. We are taking something continuous/quasi-continuous and trying to place it into discrete bins."

    My point exactly.

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    1. NickM said;
      The problems with endorsing the race concept in humans, though, is that (a) there aren't such clades to identify in humans, at least no one has yet,...

      If that statement was true, how do you explain Figure 4 from this paper*?
      http://www.plosgenetics.org/article/slideshow.action?uri=info:doi/10.1371/journal.pgen.0030104&imageURI=info:doi/10.1371/journal.pgen.0030104.g004

      -TheOtherJim

      * From Behar et al. (2007) The Genographic Project Public Participation Mitochondrial DNA Database. PLoS Genet 3(6): e104. doi:10.1371/journal.pgen.0030104

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    2. I replied to these comments, which are close to identical to comments posted at PT (including the broken tinyurl link).

      My replies start at:
      http://pandasthumb.org/archives/2012/02/continuous-geog.html#comment-279877

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  9. ***As I noted in my post, you could literally just throw a bunch of points on a globe in a grid pattern, exclude those that fall in water, measure the geographic distances between the points, and get this sort of "clustering". If genetic distance between humans is mostly smooth and continuous (in pre-1500s populations)***

    See Rosenberg on "Clines, Clusters, and the Effect of Study Design on the Inference of Human Population Structure" 2005:

    "For population pairs from the same cluster, as geographic distance increases, genetic distance increases in a linear manner, consistent with a clinal population structure. However, for pairs from different clusters, genetic distance is generally larger than that between intracluster pairs that have the same geographic distance. For example, genetic distances for population pairs with one population in Eurasia and the other in East Asia are greater than those for pairs at equivalent geographic distance within Eurasia or within East Asia. Loosely speaking, it is these small discontinuous jumps in genetic distance—across oceans, the Himalayas, and the Sahara—that provide the basis for the ability of STRUCTURE to identify clusters that correspond to geographic regions."

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  10. My point exactly.

    I guess then that you manage to live your life without ever using such discrete bins as "color green", "small planet", "high mountain" and thousands of others. Damn, do you even pause to think about it before spouting nonsense?

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  11. Matzke cites Templeton saying the level of differentiation amongst humans is below that usually used for sub species. Templeton was wrong. He based this comment on a misreading of a paper Smith et al 1997 "Subspecies and Classification”.

    Templeton (1998) states:

    ***A standard criterion for a subspecies or race in the nonhuman literature under the traditional definition of a subspecies as a geographically circumscribed, sharply differentiated population is to have F* values of at least 0.25 to 0.30 (Smith et al. 1997). Hence, as judged by the criterion in die nonhuman literature, the human Fn value is too small to have taxonomic significance under the traditional subspecies definition…Although human “races” do not satisfy the standard quantitative criterion for being traditional subspecies (Smith etal. 1997)…***

    (Templeton, 1998. Human races: a genetic and evolutionary perspective

    Here’s what Smith et al actually said:

    “The non-discrete nature of subspecies is evident from their definition as geographic segments of any given gonochoristic (bisexually reproducing) species differing from each other to a reasonably practical degree (e.g., at least 70-75%), but to less than totality. All subspecies are allopatric (either dichopatric [with non-contiguous ranges] or parapatric [with contiguous ranges], except for cases of circular overlap with sympatry); sympatry is conclusive evidence (except for cases of circular overlap) of allospecificity (separate specific status). Parapatric subspecies interbreed and exhibit intergradation in contact zones, but such taxa maintain the required level of distinction in one or more characters outside of those zones. Dichopatric populations are regarded as subspecies if they fail to exhibit full differentiation (i.e., exhibit overlap in variation of their differentiae up to 25-30%), even in the absence of contact (overlap exceeding 25-30% does not qualify for taxonomic recognition of either dichopatric populations or of parapatric populations ….

    …..The use of multivariate statistical procedures can provide approaches that are reasonably objective and not dependent on preconceptions about taxonomic membership. Nonetheless, the discriminatory power of such methods depends critically on the quality of the characters being analyzed and, in addition, the adopted standard for level of differentiation required for taxonomic recognition. Multivariate analyses (Thorpe 1987) are useful techniques for substantiation of subspecific validity, with revival of the now generally neglected 75% (or similar) rule (idem:7)***

    (Smith et al., 1997. Subspecies and Classification)

    Not only do they not discuss Fst, but based on their criteria, human populations clearly qualify as subspecies. The 70-75% they refer to is the percent of correct assignments of individuals to a population (see: Amadon, 1949) . With humans, using multivariate analyses, individuals can be assigned to populations with well over 90% accuracy.


    Also if you look at the figures for the level of genetic diversity within humans it appears similar to other mammals that have various races or sub species.

    (eg Woodley 2009) http://tinyurl.com/7wsb43d



    "Humans show only modest levels of differentiation among populations when compared to other large-bodied mammals, and this level of differentiation is well below the usual threshold used to identify subspecies (races) in nonhuman species."

    However, if you read Templetons'
    Templeton’s comment that the level of differentiation is below the usual threshold is based on his own misreading of the Smith et al 1997 Subspecies and Classification” paper.

    Also if you look at the figures for the level of genetic diversity within humans it is actually quite similar to other mammals that have various races or sub species.

    (eg Woodley 2009) http://tinyurl.com/7wsb43d

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    1. This (and everything else) has been pointed to the "race is not real" crowd a few zillion times already. All to no avail. As entirely expected from a debate that is not rational in its nature. If 2x2=4 could be used to support the concept of geographic races, the PC brigade would be denying it and saying that 2x2 *can* be 5 because, after all, math is probably not objective.

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  12. Races are biologically real, but the biologically identifiable races are not "black/Negroid", "white/Caucasoid", "Asian/Mongoloid" of the Noachian tale. Those are socioculturally constructed races. Also, because "race" or "subspecies", which are pretty much synonyms, do not have an objective operational definition such as the biological species concept, there is a vast hierarchy of groupings that could all be considered races.

    This is similar to all other taxonomic levels, other than sexually reproductive species defined by a strict application of the BSC, and also similar to asexual species.

    Cladistics can identify a monophyletic group (=clade), but cladistic analysis can't tell you if the clade so identified is a phylum, class, order, family or genus. Such analysis can tell you its hierarchical position relative to other groups (e.g. what clades include clade X as a subset and what clades are subsets of clade X), but there is no objective definition for what group constitutes a "class". A particular class might be defined by the presence of a synapomorphy, but class in general is not defined.

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  13. I could go on forever about the outrageous cover art, and I haven't even read the article. My first reaction was that these women all look the same, reminding me of the way that Asian models and actresses popular in the west often have the most caucasian features. All 6 faces have the same bone structure, hairline, ear placement, nose length, inter-ocular distance, etc.

    My next reaction was "duh, of course they look the same, because this is photoshopped". Or (less plausibly) it's the same model, with a really good make-up artist plus a little bit of photo-shopping?

    And then I started to ponder the real questions, namely (1) why does Scientific American fake its cover art to represent racial differences? and (2) why are the faked racial characterizations so subtle? I think the two questions are related. You won't find any domed brows or big noses or fat lips here. The art is an attempt to suggest race without invoking any racial stereotypes and without offending anyone.

    After all, the classic fallacy of typology in biology (and life) is to represent a species with a single specimen or archetype. They can't possibly succeed with this 6-faces layout-- unless they could take 6 sets of 100 women (clustered by some arbitrary genomic markers) and use graphics to make a composite image of each set of 100 faces.

    Anyway, I don't really see 6 races here. That counts as a failure, unless of course, the message of the article (which I haven't read) is that there really aren't races.

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  14. I disagree that "nobody is arguing for an old-school typological or "discrete" race concept". I think that Mason nailed it by pointing out that "race" has a specific meaning for the public that we are usually addressing.

    As a specific example of discrete races being recognized, see hydrazine indicated by the FDA for use in African Americans oh-so-long-ago in 2005. The group being recognized is very exactly the socially recognized "race".

    I fail to see how it can be constructive to write that we find geographically structured genetic variation in humans, thus races. Rather, we should write that we find geographically structured genetic variation in humans, period. Then let's move ahead with genomic tests which are predictive of drug response, at the individual level.

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    1. You might want to get Dr. Moran to fix the name of the drug. It's hydralazine, not hydrazine. :)

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    2. Oups, thanks for the correction.

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  15. @ M

    You proposed this reference.

    Sorry but there’s to many errors in this paper to cite it as a serious reference.

    For instance this table is seriously dubious. Why? Because this table compares measurements performed on the mtDNA with measurements performed on the genome. And when we compare the diversity within Pan troglodytes compared to the diversity within Homo sapiens it appears that chimps are much more diverse than humans even based on the Nuclear DNA.

    Oh and there were more divergence between Homo sapiens and Neanderthal than between the various modern human populations. I quote John Hawks:

    The present study shows that Neandertals were at a minimum partially isolated from their contemporaries in Africa, and that the genetic divergence between those populations was larger than the genetic differences between European, Asian, and African populations today. John Hawks

    But in fact this table (and thus your reference) is dubious because the table in question originates in a highly racist book called "Erectus walks Amongst Us", written by one Richard D. Fuerle (Yes this book is cited as a reference for the table!). This book is racist and not scientific. In this book you can read this particular kind of talk:

    Today, white men in the military fight all over the world, but they do not fight for the one thing that is most important to the survival of their kind – who impregnates their women. They not only condone the impregnation of white women by other races, they not only facilitate it, they actually celebrate it! Richard D. Fuerle

    And so in the future better check your sources

    Thank you!

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    1. Speaking of that table, where the hell did they get a genetic distance for humans vs. Homo erectus?

      It says: "Human vs. Homo erectus (inferred)". Looking up the reference:

      Curnoe, D. and A. Thorne (2003). "Number of ancestral human species: a molecular perspective." HOMO - Journal of Comparative Human Biology 53(3), 201-224.

      Basically they take the time for H. sapiens vs. H. erectus from the fossil record, and molecular rates from other clades, and extrapolate what the distance "would be". This is actually mildly interesting, e.g. if we ever got lucky and got DNA from an erectus, but it's not data at the moment. And there are huge problems with even defining erectus, as the taxon is virtually certain to be paraphyletic.

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    2. The table I understand actually was put together by John Goodrum on Race FAQ.

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  16. Larry, it was probably unfortunate that you invoked the Herring Gull ring species to illustrate your point. First, it isn't actually a ring species. Second, ring species would seem to make Nick's point, not yours and Jerry's. Yes, they do indeed create problems for species concepts.

    Anyway, check this:

    Lievers, D., P. de Knijff, and A. J. Helbig. 2004. The herring gull complex is not a ring species. Proceedings of the Royal Society of London, Series B 271:893-901.

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    1. The Wikipedia article refers to studies that question the "ring species" concept but that wasn't the point.

      Nick's point was more like saying that the gull data indicates that species, subspecies, and races don't exist because the edges are fuzzy. Do you agree with that point?

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    2. Hehe. Apparently we've switched sides on demarcation arguments!

      I'll agree that species can be objectively distinguished in many instances, despite occasional blurriness and intermediates and lack of a One True Perfect Definition of species, if you'll agree that science and pseudoscience can be objectively distinguished in many instances, despite occasional blurriness and intermediates and lack of a One True Perfect Definition of science.

      That said, humans haven't reached anything like the level of even a ring species, there being no infertility pattern whatsoever. The relevant "level" to argue about is subspecies, but (a) everyone agrees that their definition is much squidgier than "species", and (b) if you look at the various definitions usually used for subspecies, humans don't seem to quality.

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  17. I completely disagree with your interpretation of Nick's point. Go ahead and read the gull paper, for one thing. It doesn't say what you seem to imagine it says. And it isn't that -- in the human case specifically -- the edges are fuzzy. That would be so if there were, for example, some kind of narrow hybrid zones. But with the human species it's all edges, all fuzziness. Isolation by distance and nothing much else. This wouldn't count as having subspecies for any other species either. Many subspecies in songbirds, for example, were erected just to cover clinal variation and have been abandoned because the subspecies only work if you consider only end members and ignore the clines.

    There are some good ring species, the best being the West Coast Ensatina complex. And a good ring species will cause trouble for any species concept. Just goes to show you that "species" is a good enough abstraction of true biological variation much of the time, but not all of the time. Same with subspecies: works great for long-term geographically isolated populations, not so well otherwise.

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  18. ***But with the human species it's all edges, all fuzziness. Isolation by distance and nothing much else. This wouldn't count as having subspecies for any other species either***

    Can you elaborate on this? This seems contrary to what Rosenberg et al found with their paper on Clusters & Clines (see excerpt above).

    Also, it seems that:

    a) There are (some) genetic clusters/clades.
    b) Members share (or did share ) a unique geographical range or habitat
    c) Members share a unique natural history relative to other subdivisions of the species.
    d) Members share patterns of heritable phenotypic differences (frequency).

    This seems consistent with O’Brien and Mayr’s (1991) criteria. Also, see Mayr's comments here:

    …No matter what the cause of the racial difference might be, the fact that species of organisms may have geographic races has been demonstrated so frequently that it can no longer be denied. And the geographic races of the human races – established before the voyages of European discovery and subsequent rise of a global economy – agree in most characteristics with the geographic races of animals. Recognizing races is only recognizing a biological fact. (Mayr, 2002. The biology of race and the concept of equality).

    http://tinyurl.com/88489wt

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  19. Geographic structure is not the same as subspecific differentiation. You can come up with unique geographic clusters provided you don't sample adequately across the intervening distance. Barriers, unless there is complete geographic isolation, merely increase the effective distance. But what Rosenberg et al. show is simply explained as isolation by distance. Yes, people in Morocco are different from people in France. And more different than the straight line distance would suggest. But if you take a transect across Africa to Egypt, across the Middle East, through Turkey, and west through Europe, where is the dividing line?

    And Ernst Mayr, brilliant scientist that he is, presents no argument about this in the chapter you cite. Most valid subspecies are allopatric and would qualify as phylogenetic species. There's none of that in H. sapiens.

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  20. **But if you take a transect across Africa to Egypt, across the Middle East, through Turkey, and west through Europe, where is the dividing line?***

    Subspecies aren't pure categories in whatever species they are found. Almost every subspecies (not necessarily every individual member of the respective subspecies though) has some admixture from other subspecies. In contact zones of different subspecies, admixture from other subspecies rises to high levels and we classify such individuals and groups as hybrids of different subspecies.

    Neil Risch also notes:

    "The continental definitions of race and ancestry need some modification, because it is clear that migrations have blurred the strict continental boundaries. For example, individuals currently living in South Africa, although currently Africans, have very different ancestry, race and ethnicity depending on the ancestry of their forbears (for example from Europe or Asia) and the degree to which they have remained endogamous. For our purposes here, on the basis of numerous population genetic surveys, we categorize Africans as those with primary ancestry in sub-Saharan Africa; this group includes African Americans and Afro-Caribbeans. Caucasians include those with ancestry in Europe and West Asia, including the Indian subcontinent and Middle East; North Africans typically also are included in this group as their ancestry derives largely from the Middle East rather than sub-Saharan Africa. 'Asians' are those from eastern Asia including China, Indochina, Japan, the Philippines and Siberia. By contrast, Pacific Islanders are those with indigenous ancestry from Australia, Papua New Guinea, Melanesia and Micronesia, as well as other Pacific Island groups further east. Native Americans are those that have indigenous ancestry in North and South America. Populations that exist at the boundaries of these continental divisions are sometimes the most difficult to categorize simply. For example, east African groups, such as Ethiopians and Somalis, have great genetic resemblance to Caucasians and are clearly intermediate between sub-Saharan Africans and Caucasians [5]. The existence of such intermediate groups should not, however, overshadow the fact that the greatest genetic structure that exists in the human population occurs at the racial level."

    http://genomebiology.com/2002/3/7/comment/2007

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  21. I disagree with Risch on the meaning of those findings. It just tells me that there are no races. Not only are there easily found intermediate populations, the continental "races" he finds are as different across distances than are populations he would assign to different races *if* the distance counted is not across an ocean but through an inhabited region. Such as, for example, a transect down the Nile.

    And we really should contrast distinct subspecies, with at most narrow hybrid zones at meeting points, with simple isolation by distance, in which the distribution of differences is fairly continuous.

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  22. I wonder if anyone of color or other population of historically or socially oppressed people are participating in this thread. If so, what do you think?

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    1. What makes you think that groups that could be defined as races / subspecies actually correlate to the prejudiced stereotypes of the past?

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    2. Why should anyone care? That's the great thing about the internet: nobody knows you're a dog. You have to rely on actual arguments.

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  23. The best way to undermine a person's own faith in the division of humanity into a set of "fuzzy races" is to simply ask them to name/mark/delimit those "races" and list the factors (geographical/morphological/etc) they used.

    After many rounds of trying to convince everyone (in their OWN camp) that THEIR schema is the correct one, the budding "race realist" will realize the arbitrariness of it all and just give up.

    Everyone who agrees that humanity is split into "races" will NEVER try to define/number/delimit them. It's just too damaging to their own camp.

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  24. ***Everyone who agrees that humanity is split into "races" will NEVER try to define/number/delimit them...will realize the arbitrariness of it all and just give up.***

    Not really. Just start with the subspecies concept and its criteria, see how the criteria are applied in practice, and evaluate human populations.

    From O'Brien & Mayr, 1991:

    "Members of a subspecies share a unique geographical range or habitat, a group of phylogenetically concordant phenotypic characters, and a unique natural history relative to other subdivisions of the species."

    (O’Brien and Mayr, 1991. Bureaucratic Mischief: Recognizing Endangered Species and Subspecies.)

    It doesn't seem that hard to find populations that meet that criteria (see Sesardic 2010, also table 1 in Gill (1998) “Craniofacial criteria in the skeletal attribution of race.”).

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  25. Those blacks with white admixture are now whites, and those whites with black admixture are now black.So much for that nonsense about one drop of black blood making one black!
    Ah, that second part seems to qualify under the old standard,but people prattle about passing as white, and some who look white call themselves black.
    Anyway,racism is so stupid!
    I welcome those of further off lines of Lamberths who say that they have Inidan ancestory but actually black instead! I have a biracial baby cousin on the Lynn line two families away. Gee, and I was a racist from around eleven until sixteen1

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  26. The arguments and this post could be summed in two statements:

    1) What the average person believes is a race is a social construct.
    2) While there may be biological differences among different groups in the population- it is not particularly useful for any field of biology to investigate these differences in a manner attempting to explain macro-level phenomena beyond the level of systems physiology (beyond meaning concepts such as behaviour, personality).

    The last statement is not motivated by social responsibility or political correctness, simply put the science and tools available to make these assertions with confidence are not available, therefore any claims made would be, in my opinion, a result of bad science.

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  27. I have the opinion that the so called "race-realists" are more "vocablephiles" towards race than "realists" in any substantial way.

    Even somewhat less realists, as in their hurry to reinstate the vocable "race", the actual taxonomic delineation is left undefined, and the traditional/folk delineations do more to hurt than to help the understanding of the underlying biological diversity, which, more often than not, does not seem to be denied by any of the supposedly "race-deniers".

    At the same time, race "realists" won't deny that we can't delineate human populations as "discrete entities" in a species-like/creationist-like way, accepting that it would got to indeed be fuzzy, and fuzzier, less precise than species. That whatever the eventually consensual/standard "races" would be, they'd probably be much more like the common understanding of "populations" than the common understanding of "races". But the term "race" got to be used anyway, and it's just "denial" and PCness not to...



    There are some "vocablephobes" in the other side anyway. But I think most people with some biological knowledge who are labeled as "race deniers" would be satisfied if, instead of having more concern with a political discourse (oh, the irony) of reinstating the term "race" and saying that "races exist", "race-realists" reached to some consensual/standard taxonomy, and, when speaking to the lay public, were more emphatic that actual races do not give validity to old, creationist-like or racist notions, and that they do not even necessarily match the social concept, that we can have someone who's "socially black", but is genetically/racially more "white", and so on.

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  28. It's interesting how so many people are racist and believe that one race needs to date and marry the same race. Dogs mate with different types of dogs and the cross breeds live longer then the pure breeds. Something to be said. Genetic differences from different people through their ethnically my improve life span and quality of life.

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