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Author | Topic: Human Races | |||||||||||||||||||||||||||
Too Tired Inactive Member |
Mammathus writes:
---------I don't deny that populations have diverged. I don't even deny that some populations may have private polymorphisms, little gene flow, etc. But to ascribe these differences to a level "race" that has biologically been ascribed to a sub-species level distinction is preposterous. --------- I've never understood why so many people think that 'races' in the human species should be qualitatively different from 'subspecies' in other animals. They're both generally fuzzy categories and both traditionally based on more-or-less consistent observable morphological differences. I've looked at the genetics of both categories and there's not much difference there, either. See my not-very-well-written paper, "The Race FAQ" at Just a moment... and at least read my critique of Templeton's 1998 paper on race at the end. Also there's some interesting stuff from Klein & Takahata, Cavalli-Sforza in his pre-race-denial days, Sewall Wright and others. Cheers, John
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Too Tired Inactive Member |
Mammathus writes:
quote: Thanks, I appreciate the compliment.
quote: I didn't really say that cultural definitions of race are inaccurate, but I don't know exactly what you mean by "accurate" so I won't pursue it right now. Looking at the phylogeographic subspecies definition isn't so much a matter of advocating a reassignment of terms, it's an attempt to get a definition on the table that has the blessing of some prominent biologists in the field of non-human taxonomy (John C. Avise, Stephen J. O'Brien, Ernst Mayr, EO Wilson et al.) so that the subspecies synonym "race" which we use for humans might be given some guidelines. So much of the race debate is about how to define race in the first place, with endless silly arguments about the 'Dubliner race', the 'Bronx race', the green-eyed race, etc etc. The phylogeographic subspecies concept was developed to ensure that those populations called 'subspecies' are evolutionarily significant segments of a species. Its use still requires the sound judgement of biologists, and the subspecies level of taxonomy is and will always be fuzzy practically by definition, but it's still a big improvement over the way subspecies have too often been assigned in the past. In the studies I've read that employ this definition, many or even most of the classical subspecies don't meet the criteria, in other words it's a lot tougher to be named a subspecies under this definition than under the older definitions of the term. Phylogeographic subspecies are more distinct species segments than classical subspecies, which in many cases weren't very distinct at all. What's the relevance to the race debate? Well, there's recent population genetic data on these phylogeographic subspecies that can be compared to population genetic data for humans. That allows us to assess the claim that we hear so often about how human populations are NOTHING like subspecies. As it turns outs, some human populations are an AWFUL LOT like subspecies, in terms of morphology AND in terms of genetic population structure. To my way of thinking, that's highly relevant to the race question, in fact it answers the question. The rest is just squabbling over details, which is all well and good but is quite apart from debating whether or not human races exist. John
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Too Tired Inactive Member |
SFS writes:
quote: When I wrote the paper, autosomal microsatellites were the marker of choice and about the only option for comparing a dozen or more species. I know that chimps have more SNP diversity than humans, but I think it's illuminating to look at as many species as possible to get a sense of how humans rank, and comparable SNP data wasn't available. In terms of population structure (how the diversity is partitioned) I have a second-hand reference (the original was in an unpublished doctor's thesis) to an Fst value of .02 between I believe P.t.troglodytes and P.t.vellerosus, two supposed subspecies yet quite a bit less distinct than most human groups, according to this data. But there hasn't been a good comprehensive study of wild chimp population structure done using autosomal markers, it's all been mtDNA which is a single locus and not wholly reliable.
quote: To be honest it's not an aspect of the debate that interests me. Supposedly there's all this confusion over what race means to the man on the street or the college freshman or whomever. It's not something I've encountered but I'm not in a position to know if it's out there or not. (The one thing I've noticed is that people who argue against human races tend to think of race as a synonym for species.) The issues of hypodescent and admixture certainly have their place but they don't have much bearing on the race question as I see it. I mean, do you actually know somebody who would consider a European-looking person black because he or she had 1% African ancestry? Maybe you do, but just because a term or concept can't be idiot-proofed doesn't mean it has to be discarded. John
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Too Tired Inactive Member |
Mammathus writes:
quote: It could amplify or diminish your sense of human group diversity depending on what your original sense of it is. But in any case it at least gives an accurate view of our species diversity with respect to that found in other mammals.
quote: No, forest and savannah elephants were given SPECIES designations based on strong genetic distinctiveness which indicates very limited gene flow between the two. I have both the Roca et al. article and the Comstock et al. from Molecular Ecology, which I'm happy to email if anyone wants them. I might be misreading you, but it sounds like you're failing to make a crucial distinction between the terms 'subspecies' and 'species'. To my knowledge nobody in modern times is advocating the existence of different SPECIES within extant humans, so of course the level of genetic difference between these elephant species is much greater than what's found in humans. It's the SUBSPECIES level of taxonomy that's useful to examine for the race question in humans. Incidentally, the Comstock paper gives microsatellite Fst values of .07-.08 for the major geographic groups of the savannah species (L. africana), less distinct by this measure than the traditional human races, and so without some compelling morphological differences between them there probably will be no effort to name subspecies within savannah elephants.
quote: Again, no, in this case the genetics indicate a general lack of gene flow between forest and savannah elephants even when a population of one species is in closer proximity to the other species than to another population of its own. There's evidence of minor hybridization but not enough to threaten the genetic integrity of either species. This case puts you squarely into the biological species concept, and the phylogeographic subspecies concept doesn't enter into it.
quote: It happens all the time - that's taxonomy for you. Consider the Lake Victoria cichlids or Darwin's finches.(Just a moment...) There are full-blown species within these groups that have only formed in the past ten thousand years or so. These different species are nearly indistinguishable genetically and yet they're considered full species because they've evolved mechanisms that reproductively isolate them from other such species. They're clearly less distinct genetically than are the major human groups, but human groups are merely races because they freely (more-or-less) interbreed. So taxonomy at the lowest levels is really more about reproductive isolation than about length of separation. Race, subspecies, species - each of these taxa can accomodate a wide range of genetic relatedness. Human races aren't especially distinct as races/subspecies go, but the human species is not especially homogeneous, either.
quote: It's true that anthropologists tend to be hopelessly confused by the term, but fortunately the rest of us can get along with it just fine. John
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Too Tired Inactive Member |
Mammathus writes:
quote: I'm not familiar with the morphological differences that led to the former subspecies designations for forest and savannah elephants in Africa, but the lack of gene flow is readily apparent in the genetic data for people who have genetically characterized a lot of different species. I don't know where the difficulty is you're talking about. In my humble opinion Fernando et al. have overinterpreted a small amount of genetic data in trying to support their hypothesis that the Borneo elephants have Pleistocene origins. Maybe they're right, but there's nothing in their analysis of six loci that argues strongly against the 16th-18th century introduction hypothesis. It's up in the air whether the Borneo population should be considered a true subspecies even with those big pairwise Fst values. Look at the microsatellite heterozygosity - .014 compared to .7-.8 in humans. Fst is basically (Ht-Hs)/Ht so when Hs is practically nil like in these elephants, Fst is not very meaningful. Lack of gene flow with other populations is obvious though from the severe loss of alleles, most likely due to drift in a small isolated population. Whether it's been happening for 300 years or 10,000, who knows.
quote: What's a "strict racial category"? Sounds like an oxymoron. How much gene flow is "extensive"? You can't build a very solid case against human races using vague terms like these. You have to show us that gene flow has indeed been "extensive" compared to gene flow among groups within lots of other species. Stephen O'Brien has said publicly that people who don't believe in the biological reality of human races are basically ignorant of population genetics, although he said it more nicely.
quote: Of course evolutionary histories are not equivalent. But why shy away from a comparative approach? You were using one yourself when you wrote that it's preposterous to compare human group differences to those found among subspecies.
quote: Well, you can propose some new terminology if you like. I agree that it would be wasted effort to try to precisely categorize all humans into racial categories, but it works pretty well for several billion people and at least provides a frame of reference for the rest. Your new terminology will have to do at least that well. John
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Too Tired Inactive Member |
Mammuthus writes:
quote: My stance in this debate is that the racial division of humans is the default position, the status quo, and that the campaigners against human races have to convince us otherwise. So, slightly differently from how you've characterized Peter's take on genetics, I'd say that the evidence *against* human races is *not* found in genetic data. On the other hand, knowing as we do that human groups are interfertile and knowing what the population genetics of other subdivided species look like, I wouldn't argue much with Peter's assessment. As far as a definition of race, not only have I provided some quite in-depth discussions of the concept from various experts on my web site Just a moment... but I've provided an actual working definition of subspecies in my race faq which I can offer as a definition of race as well since I consider the terms to be synonymous. If I've overlooked a similar contribution by yourself in this thread, please point me to it. Which racial divisions to accept: well, for the major races Cavalli-Sforza preferred (prefers?) the Big Three, Wright would add Amerindians for four, five works well too, but I agree completely with Klein & Takahata that the number doesn't matter, you can be a lumper or a splitter as you wish.
quote: I agree that similar genetic make-up can be the result of very different evolutionary histories, but taxonomic terms aren't really intended to describe evolutionary histories - that would be a tall order. I'm not aware of any evidence or reason to think that extant humans have evolved by sympatric speciation. I would agree that sub-Saharan Africans comprise a major human race (and therefore, technically, a subspecies). I'm not aware of there being more than one species of H. sapiens.
quote: Like I said, it's always about definitions. The vast majority of people in the world who have had any amount of exposure to racial diversity probably have a very adequate sense of what race means. There's any number of concepts that we deal with all the time that aren't and can't be precisely defined - it makes no difference. All this agonizing over how race is defined just doesn't ring true, especially when it comes from those who haven't figured out how the term is used in non-human taxonomy. John
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Too Tired Inactive Member |
quote: We'll certainly have to talk differently about race if the degree of racial admixture found in Brazil ever becomes the norm in the rest of the world. Thanks for bringing the Scientific American issue on race to our attention. John
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Too Tired Inactive Member |
quote: In any case, racial admixture in Brazil is much more advanced than in the US.Parra et al. 2003 in PNAS Just a moment... estimated the proportion of African admixture in rural "whites," "intermediates" and "blacks" as 31-32%, 45-48% and 51-52% respectively. An earlier article by Parra et al. in AJHG, p1839 here:http://www.journals.uchicago.edu/...rnal/contents/v63n6.html sampled 9 major US cities and found an average of about 17% European admixture in blacks (i.e., ~83% African ancestry) and only about 1% African admixture in whites in a sample of three cities. I don't have any handy references but it's a reasonable guess that admixture of the major races is negligible or nearly so in much of East Asia, Europe and sub-Saharan Africa. John
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Too Tired Inactive Member |
Mammathus writes:
quote: No, the burden is on you because the division of humanity into geographical races has been recognized for hundreds of years.
quote: How so? Please elaborate.
quote: Since you've compared the common view of race to the subspecies definition and found them to differ, you imply that you can define this common view of race for us. Why don't you go ahead and give it to us, since Peter and I can't seem to please you with our sorry attempts? Just look it up in the dictionary if that helps. I am really quite curious to know how you define 'race' such that human populations don't qualify.
quote: Based on what I understand to be a reasonable definition of the term race or subspecies. I wouldn't consider sub-Saharan Africans to be a different species because they don't meet the criteria of the biological species concept, which I take to be the most common species concept among biologists at the present. Why do you want to argue this with me? Why don't you argue it with someone who believes in different human species? Or are you really incapable of drawing distinctions between these taxonomic categories?
quote: Your reading comprehension leaves something to be desired, but in terms of the major races I'd say you're Caucasian.
quote: Again your reading comprehension seems lacking. Please identify in which post or posts I claimed any of these things.
quote: My favorite debating tactic is to keep the issue as simple as possible. My point in this debate can be summarized as follows: the differences between major human populations (those we commonly refer to as major 'races') are not substantively different from the differences between the subspecies of other mammal species. Therefore, to claim that human races don't exist requires that we define race to be more like 'species' than 'subspecies' (which in my opinion is hard to justify.) Now, you can alternatively argue that we shouldn't refer to human populations as races because the concept of race (or subspecies) has too many shortcomings, but that's distinct from arguing that human groups aren't races because they wouldn't qualify as subspecies. I don't think I've come across anyone yet who agrees that if humans were any other species they would have subspecies, and yet argues for abandoning the term race due to its looseness. John
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Too Tired Inactive Member |
Mammuthus writes:
quote: Admixture is a simple concept. If races didn't mix when they meet, they wouldn't be different races, they'd be different species. To claim that admixture somehow nullifies the reality of different races is to ignore what it really tells us, which is that the parent groups are indeed conspecific.
quote: In many contexts race IS self-evident. It certainly was evident long before population genetics came along since it doesn't take any special training or ability to recognize consistent differences in hair form, hair color, skin color, facial traits, etc. between different geographical groups. As for these other silly claims, show me where I've said any of them. If you're so ill-equipped to argue your case that you have to resort to this sort of thing, maybe you should give it up until you've had a chance to educate yourself. John
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Too Tired Inactive Member |
quote: Okay, Svante, you're no peach yourself, you know. I'll be back soon and we'll take it one polite question at a time. John (edited, one 'a' in 'Svante') [This message has been edited by Too Tired, 12-19-2003]
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Too Tired Inactive Member |
I came across this today from: http://www.felidtag.org/...s/Educational/FactSheets/puma.htm
"As a result of this study, there is little reason to feel that 32 subspecies of puma exist in nature, and it is argued that wild populations should be reduced to only six phylogeographic subspecies. These six races are based on the fact that they all share a unique range, a group of phylogenetic concordant characters and a unique natural history relative to other subdivisions of this species." John
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Too Tired Inactive Member |
Mammuthus writes:
quote: Here are two reasonable (if imprecise) definitions of the term 'race', from my trusty American Heritage Dictionary, Second College Edition, 1985:1.) A local geographic or global human population distinguished as a more or less distinct group by genetically transmitted physical characteristics. 5.) Biol. a.) A plant or animal population that differs from others of the same species in the frequency of hereditary traits; subspecies. Here's a definition of race (from the December Scientific American article) that I consider to be unreasonable: "genetically discrete groups." And here's the opening sentence of the article "Subspecies and Classification" (the one that Templeton cites in his 1998 piece on race) Just a moment... "We regard species as genetically discrete (i.e., separate and independent) populational entities, whereas subspecies are taken as genetically non-discrete (confluent) populational entities. That distinction we regard as axiomatic despite arguments to the contrary (e.g., Barton and Hewitt 1985)." I wouldn't argue that H. Smith et al. who authored this paper are the final authorities on defining taxonomic terms, but as far as I can tell, their statement would be considered correct by a majority of biologists. So in the Sci Am piece we have yet another example of folks wanting to define 'race' as something akin to 'species' in order to claim that they don't exist. The subspecies definition I used in The Race FAQ is also imprecise but is much more formal in that it proposes a list of criteria that populations must meet in order to qualify. This doesn't necessarily make it a simple matter to actually decide which populations should properly be considered subspecies, but if you were on a panel or jury of biologists and were charged with making such a decision, this definition would give you some guidelines by which such a judgement could be made. My point in using it in the faq was not so much to argue that the major human races qualify as subspecies (although I believe they do, and I consider race and subspecies to be synonymous anyway), but rather to show that the population structure of species that do have subspecies is not much different from that found in humans. Now I've elaborated.
quote: The species concept is controversial to be sure, but the BSC is indeed the most common species concept and will probably remain so. If not, you'll need to inform me which one has replaced it.
quote: Race and subspecies are interchangeable; race and species, or subspecies and species, no. The fact that the terms get mixed up by scientists and lay people is confusion on their part. And then evolution gives us populations that don't always fit well into the taxonomic terms at hand; that doesn't necessarily mean that these conventional terms need to be discarded, or that they can be easily replaced by something that's going to be any better.
quote: I assume the world is getting more homogeneous, racially speaking.
quote: If a random sample of Nigerians and random sample of Europeans respond differently to a medical treatment of some sort, then who would be served by refusing to consider race as a factor in future treatments? Certainly there's variation between groups within sub-Saharan Africa, but not that much. The vast majority of Africans - West Africans and the Bantu speakers - are relatively homogeneous genetically, enough so that the Big Three race scheme may serve better than no scheme at all from a medical viewpoint. John
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Too Tired Inactive Member |
Mammuthus writes:
quote: Yes, same here, and I'm glad to put the hostilities behind us.
quote: My point was that the Sci Am definition of 'race' was nearly identical to Smith et al.'s definition of 'species.' Bamshad and Olson (the SciAm piece authors) are both Americans; they grew up in a place that has racial diversity and where 'race' is a common term. How did they reach adulthood thinking that blacks, whites and Orientals are different species? In fact they almost certainly didn't, so why take this term with which they are undoubtedly familiar and define it to mean something they know it doesn't mean??? It never ceases to amaze me.
quote: I understand the frustration with terminology that, as you say, means different things to different people. But what can be done? The physical differences between human groups are so striking that we can't just pretend to ignore them because we don't like the conventional terms. There would have to be new terms introduced, and what are the candidates here? Geneticists are always referring to 'ethnic groups' but that's often a poor euphemism for what should really be some sort of evolutionary term. I personally think the dictionary definition of race as "a regional group that is more or less distinct by genetically transmitted physical features" hits the nail on the head. We'll have to agree to disagree on this one. Gotta go. More later. John
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Too Tired Inactive Member |
Peter writes:
quote: I agree that 'race' and 'subspecies' can be distinct terms and that when they're used this way, 'race' implies less difference. This usage isn't uncommon, for instance this is how Nei uses the terms in his 1987 text Molecular Evolutionary Genetics. On the other hand, you can go to Google and type in "taxonomic terms race subspecies" (without the quotes) and in short order find many, many references to the terms being used as synonyms. In fact, Alan Templeton introduces his 1998 paper on race with the words, "Race is generally used as a synonym for subspecies.." and here I agree with him 100%. Recently I read Ronald Nowak's 1995 paper, "Another Look at Wolf Taxonomy" to see how he went about delineating the five subspecies in what is currently the most-accepted taxonomic scheme for the gray wolf in North America. He identified the subspecies mostly by skull and tooth metrics, and the differences between subspecies didn't seem all that remarkable. I don't recall that he provided any evidence of sharp boundaries between the subspecies' ranges, and according to microsatellite Fst values in a paper I cited in The Race Faq, the genetic differentiation between these wolf subspecies and the major human races is about the same. I could say the same thing about current puma (cougar) taxonomy. It's just not clear to me what the big difference is between these other polytypic species and humans. Not trying to be overly argumentative here. John [This message has been edited by Too Tired, 12-20-2003]
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