More about Human Populations

The post from yesterday was inspired by the news coverage surrounding the paper describing gene expression differences (DOI) between human populations. The original article uses neither the term 'race' nor the term ''Caucasian''. Instead, what would normally be called 'races' are referred to as 'populations' -- aside from the single use of 'ethnic groups' in the title of the paper -- and the population that would be called ''Caucasian' ' is dubbed 'European-derived'.

When we look at some of the news coverage of the article, though, we see different terminology. The Nature news item by the usually excellent Erika Check refers to the different populations as 'ethnic groups' except when quoting Steve Scherer (who refers to them as 'populations'). Check also calls the European-derived population 'Caucasian'. The Scientific American coverage exhibits a similar trend -- exclusive use of 'ethnic group' or 'ethnicity' rather than 'race' or 'population' and a preference for 'Caucasian' over 'European'. The Scientist uses a hybrid of population and ethnicity, but chooses European over Caucasian.

There are two items to address here. First, are the terms above synonymous or exchangeable? Second, if they mean different things, what do they mean?

Ethnicity vs. Race vs. Population

I've been fairly explicit about my preference for 'population' over 'race'. Race is a term hijacked from biology by the general population -- originally referring to a biologically meaningful classification below the species level. The human races of the common vernacular are definitely the result of population structure -- restricted gene flow between these races -- but it's unclear to what extent these populations have differentiated. Also, the word race is pretty loaded outside of scientific dialogues, which causes me to shy away from using it. But I do see race and population as fairly synonymous; I just prefer the term population.

Ethnicity, on the other hand, is not synonymous with race or population. While race and population trace their roots to biology, ethnicity is a sociological concept. Ethnic groups are cultures -- groups of people who share beliefs, practices, languages, etc -- whereas populations are historically breeding groups of individuals. Populations take many generations to become genetically unique from each other (and they can be called races if they also differentiate in biologically meaningful ways), but ethnic groups can form within a single generation. As Razib mentioned in the comments of the previous post, an ethnic group such as 'Latino' can include many different races/populations -- European, Amerindian, and African.

If race/population and ethnicity mean different things, why do journalists insist on referring to population differences as ethnic differences? I think it goes back to my point about the stigma associated with 'race'. The journalists are uncomfortable referring to the populations as races, and many don't seem to have the term 'population' in their arsenal. So they call them ethnic groups, drawing the ire of people like me.

European vs. Caucasian

This one is a bit more straightforward. Europe is a fairly objectively recognizable geographic area: from the Atlantic Ocean to the Ural Mountains, from Scandinavia to the Mediterranean Sea, and extending somewhere into the Middle East (possibly to the Caucasus Mountains or maybe further). People who trace their ancestry to this region are of European descent.

Caucasian, literally, refers to people native to the Caucasus, but it has become interchangeable with any number of 'White' populations, most of whom trace their ancestry to Europe. One gets the feeling that the term 'White' fell out of favor and was replaced by 'Caucasian' much like 'Black' was replaced by 'African-American'. But the roots of such terminology are a bit disturbing; it was postulated that the natives of the Caucasus exhibited the idealized physical appearance so the Caucasus were believed to be the birthplace of mankind. The logic behind this idea -- the assumption that Whites exhibit the best physical appearance -- is implicitly racist. Additionally, we now know our species first appeared in Africa, so the biology isn't any good either. The connotations of the term Caucasian along with the geographical absurdity of using that term to describe all Europeans or Whites are the two main reasons we should abandon the term.

There is a difference between race and ethnicity -- one refers to biology, the other to culture -- and Caucasian is both historically loaded and geographically inconsistent. It seems like the scientists publishing research on biological differences between populations tend to use my preferred terminology -- population rather than race or ethnicity, European ancestry rather than Caucasian or White. It's the journalists (and some scientists) that chose to use the iffy terms (ethnicity and Caucasian) because the alternatives that come to mind (race and White) have fallen out of favor. They fail to realize that there are much better alternatives (population and European) that are accurate descriptors and do not carry negative connotations.

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Population in the biological sense however means something a bit different than race... Race is a group of individuals that are lumped together based on skin color, demographic history, or whatever. The cohesive force is intrinsic.

Populations are also cohesive groups of individuals, but in this case to cohesive force is geography. A population is a group of potentially interacting and interbreeding individuals. One could certainly argue that as a result of transportation at the global scale, that there are very few well defined human populations.

'caucasian' is the type of word people use if they are consulting the thesaurus too much. its novelty is far outweighed by the confusion it engenders (i've encountered individuals who think that the asian means caucasians are some form of asian).

Matt, good point about the intrinsic/extrinsic difference.

How does this sound: Both races and populations are reproductively isolated groups of the same species. Races are intrinsically isolated (due to behaviors such as host choice in fruit flies), whereas populations are extrinsically isolated due to geography. In that case, the human 'races' are really populations.

Rather than using the loaded term "Caucasion, I believe that Dr. Christopher Rock prefers to use the more modern terminology of "cracker", and prefers using this terminolgy ie, "cracker-ass crackers, when referring to dirt-poot, trailor-trash livin' populations south of the Mason-Dixon line.

And everybody loves Chris, don't they?

RPM, it's really fascinating to hear someone approach this issue from a biological point-of-view. Do you really think "race" is a term that refers to biology (besides being co-opted from the field)?

Have you ever written about it before? Do you really think there is a systematic way to define "meaningful classifications below the species level"? For humans?

The term race is commonly used in biological research. For example, in the apple-maggot fly that is used a common model of sympatric speciation (Rhagoletis pomenella) the subspecies that prefer different hosts (apples vs. hawthorns) are referred to as host races. Somewhat reproductively isolated populations of species are referred to as races as well.

I'm growing fond of the intrinsic/extrinsic difference between race and population. Basically, races would remain unique even if geographically boundaries were removed, whereas populations would collapse if they geographic boundaries were removed. My feeling is that what we refer to as races in common discourse are populations which will not persist as international migration rates increase.

Do you really think "race" is a term that refers to biology (besides being co-opted from the field)?

All people use terminology without understanding what it means (you could probably find at least one example by me in the post above). Race has a different meaning in common discourse that it does in biology. But when writing about biological research, one shouldn't employ terminology from sociological/cultural vocabularies. I know what the articles mean, but I don't like the terminology they use. It probably doesn't even interfere with our understanding of the material. But why not use proper terminology?

My feeling is that what we refer to as races in common discourse are populations which will not persist as international migration rates increase.

1) do the % for deme-to-deme migration. places like india or china won't change much. some places will change, but those are exceptions, not the rule.

2) even in places which have been closer to panmictic, e.g., brazil, phenotypic races persist because of assortative mating. the conception of 'race' is different in the united states, but it is still salient.

If India or China don't change much because migration rates aren't high enough, then they are populations not races.

The phenotpyic races may persist because the phenotypes are due to discrete units (alleles/genes) and can never blend out (y'know, the stuff you, razib, write about all the time). How much of the persistance of phenotypic races is due to the discrete nature of inheritance and how much is due to assortative mating? Also, is this assortative mating cultural or intrinsic to the phenotypic races?

The cultural vs. intrinsic hypotheses could be tested by comparing individuals from each phenotypic race reared in different cultural environments. We can do the experiments in other organisms, but such studies wouldn't be possible in humans. Generation time is too short It's immoral.

Having always thought that like many a Western European peasant my own body shape and colouring is probably more accurately described as Iberian than Caucasian I was delighted to find that genetic studies by Cavalli-Sforza and the like might support this distinction as being a valid one. Not that I need any justification for putting "other" rather than Caucasian on various official forms.

How much of the persistance of phenotypic races is due to the discrete nature of inheritance and how much is due to assortative mating? Also, is this assortative mating cultural or intrinsic to the phenotypic races?

re: discrete vs. assortative, it in brazil it seems like a non-trivial proportion is due to assortative mating. too many people are very white or very black from what i gather. as for the 'intrinsic' aspect of the mating, obviously a great deal is cultural insofar as a mixed-race individual who wants to 'pass' as white better mating with other white looking people (i say white looking because a large number of phenotypically white individuals in brazil are ancestrally quite non-white). but, one could posit psychological heuristics like "mate with those who look somewhat like you" being intrinsic.

All people use terminology without understanding what it means (you could probably find at least one example by me in the post above). Race has a different meaning in common discourse that it does in biology.

Ah, this is true. And I confess, I'm probably trying to bait you into a discussion of the biological vs. social basis of race.

But the reason for doing that is that even in political and social discourses (where maybe you would agree that the meaning of human race is most poignant), the vast majority of people would defer to the biological point-of-view, you know? I sometimes hate "appeals to science" like that. I'm an engineer, so it also gratifies my ego when people blindly put their faith in scientific dissertations, but still...

Anyway, I don't remember enough of my university genetics course to participate in a serious discussion of populations and races, even if I'd like to. From what I gather, though, you're saying:

(a) speciation isn't just a grade school exercise (I've always thought it was, really, or just a relic of 19th century naturalism), it's real biology;
(b) races/populations are integral to some theoretical biological models (like speciation), but they're not well-defined in general; and
(c) in terms of human race, official conceptions of race (like in the US census) tend to group people currently by extrinsic barriers, i.e. geographic origins.

And as globalization accelerates, these extrinsic barriers will be lowered, and human "races" as they are now most generally defined will not persist. Optimistic. I like it.

Ha, I just went to the wikipedia page on "Race" to find a list of races as they appear on the most recent US Census, and the thing is a hornet's nest. Yikes.

I think you're mixing up "speciation" (the biological process) with "taxonomy" (the human act of creating categories into which to sort groups of organisms). When we call something a subspecies, species, genus, etc, we are practicing taxonomy. When two populations are becoming reproductively isolated, they are undergoing speciation.

Anyway, what i'm saying is that the general public's definition of race differs from that of the biologists. To the biologist, the so-called races are not races at all, but populations. And they are reproductively isolated by environmental and cultural barriers (but not intrinsic properties).


Your arguments and distinctions make sense as far as they go, but they also leave some important ground uncovered.

In the end I think there's no real substitute for race, and we're just going to have to make it's proper biologically rooted meaning, informed by current science, clearer to more people. The fact is that the popularly understood approximate boundaries for the homelands of the major three or five or six races that were understood by the late 19th century or even earlier, remain broadly correct. Now many suppositions about characteristics back then were wrong, and the whole platonic discrete essential "essences" of "the races" is wrong, but that's a different thing. THAT's what especially needs even more correcting in the popular conception - though of lot of that correcting has in fact o occurred.

The trouble with such terms as "European derived population" is that it leaves out a great many people who are in the "Caucasian" meta-race. E.g. Iranians and Arabs and North Africans and South Asian Indians. The trouble with "Africans" is that it includes North Africans, who are primarily Caucasian (Berbers, Arabs, etc.) though with some sub Saharan African (black/Negro) admixture in many places.

The trouble with substituting the word "populations" is that it's popular meaning is entirely arbitrary. E.g. the American population includes many races but hardly all people. It's a geographic and political category when used that way. It's far more often used to make non biological distinctions than biologically rooted ones.

At the level of three major races we have Caucasian, Negro (or sub Saharan African since "Negro" is now so disliked by those it describes) and Mongoloid. (It's also entirely consistent with the genetic evidence to divide humanity into only two major races, sS Africans, and everyone else, according to Cavalli-Sforza - though he always uses "populations" as opposed to the politically dangerous "races".) At the more reasonable level of five we break out Mongoloid into i) NE Asians, ii) SE Asians including Oceania, and iii) AmerIndians. At the level of six we stop ignoring the relatively small in number but quite anciently distinct Papuans/Aborigines. One can go on subdividing and also separately naming clinal inbetween populations for a very long time into even thousands of micro races, all on a genetic inbreeding (for the most part) population basis, as Cavalli-Sforza's pioneering work has amply demonstrated. Distinctions between micro races might not usually be very meaningful for most purposes, but they can be fairly reliably discerned.

On the other hand distinctions between the races at the level of between three and six anyway are quite meaningful - but it's very politically incorrect to say in what way - or at least many of the ways. Differences in susceptibility to different genetic and non genetic diseases is more grey area acceptable in many quarters, though certainly not for the zealously PC.

Does mixing human populations (RACES) decrease population specific diseases? If so, will someone please suggest an article or book that scientifically shows this?