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Genetic variation, classification and race

Genetic variation, classification and ‘race’

Lynn B Jorde & Stephen P Wooding

Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA

Nature Genetics 36, S28 – S33 (2004)  Published online: ; | doi:10.1038/ng1435

New genetic data has enabled scientists to re-examine the relationship between human genetic variation and ‘race’. We review the results of genetic analyses that show that human genetic variation is geographically structured, in accord with historical patterns of gene flow and genetic drift.

Analysis of many loci now yields reasonably accurate estimates of genetic similarity among individuals, rather than populations. Clustering of individuals is correlated with geographic origin or ancestry. These clusters are also correlated with some traditional concepts of race, but the correlations are imperfect because genetic variation tends to be distributed in a continuous, overlapping fashion among populations. Therefore, ancestry, or even race, may in some cases prove useful in the biomedical setting, but direct assessment of disease-related genetic variation will ultimately yield more accurate and beneficial information.

Figure 1: A neighbor-joining network of population similarities, based on the frequencies of 100 Alu insertion polymorphisms.

The network is rooted using a hypothetical ancestral group that lacks the Alu insertions at each locus. Bootstrap values are shown (as percentages) for main internal branches. (Because of the relatively small sample sizes of some individual populations, bootstrap values for terminal branches within main groups are usually smaller than those of the main branches, indicating less statistical support for terminal branches.) The population groups and their sample sizes are as follows:

Africans (152): Alur, 12; Biaka Pygmy, 5; Hema, 18; Coriell Mbuti Pygmy, 5; a second sample of Mbuti Pygmy from the Democratic Republic of the Congo, 33; Nande, 17; Nguni, 14; Sotho/Tswana, 22; Kung (San), 15; Tsonga, 14. East Asians (61):

Cambodian, 12; Chinese, 17; Japanese, 17; Malay, 6; Vietnamese, 9. Europeans (118): northern Europeans, 68; French, 20; Poles, 10; Finns, 20. South Indians (365): upper caste Brahmin, Kshatriya and Vysya, 81; middle caste Kapu and Yadava, 111; lower caste Relli, Mala and Madiga, 74; tribal Irula, Khonda Dora, Maria Gond and Santal, 99.

Figure 2

A neighbor-joining tree of individual similarities, based on 60 STR polymorphisms, 100 Alu insertion polymorphisms, and 30 restriction site polymorphisms.  The percentage of shared alleles was calculated for all possible pairs of individuals, and a neighbor-joining tree was formulated using the PHYLIP software package. African individuals are shown in blue, European individuals in green and Asian individuals in orange.

Figure 3

(a) Results of applying the structure program to 100 Alu insertion polymorphisms typed in 107 sub-Saharan Africans, 67 East Asians and 81 Europeans. Individuals are shown as dots in the diagram. Three clusters appear in this diagram; a cluster membership posterior probability of 100% would place an individual at an extreme corner of the diagram.

(b) A second application of the structure program, using the individuals shown in a as well as 263 members of caste populations from South India. Adapted from ref. 32.

Figure 4

A neighbor-joining tree formulated using the same methods as in Figure 2, based on polymorphisms in the 14.4-kb gene AGT.

A total of 246 sequence variants, including 100 singletons, were observed. The 368 European, Asian and African individuals are described further in ref. 54.

Author’s conclusion: “Race remains an inflammatory issue, both socially and scientifically. Fortunately, modern human genetics can deliver the salutary message that human populations share most of their genetic variation and that there is no scientific support for the concept that human populations are discrete, nonoverlapping entities.

Furthermore, by offering the means to assess disease-related variation at the individual level, new genetic technologies may eventually render race largely irrelevant in the clinical setting. Thus, genetics can and should be an important tool in helping to both illuminate and defuse the race issue.”

Note by RK about -> ” there is no scientific support for the concept that human populations are discrete, nonoverlapping entities.”
– Outside of racist groups, no scientist makes such a claim. This article does not debunk the idea that biological groups for humans exists: It clearly shows that such groups exist, in precise detail. However, this data debunk claims made from people using non-scientific definitions of  words.

When scientists use words like “race”, “populations” or “clades”, these words have precise meanings. Every discovery in biology and evolution over the last 200 years has clearly shown that the basic concept of biological groups has to exist. All forms of life have family trees that develop in ways that can be represented by cladograms, and those cladograms show evolutionary phylogenies.

“A clade is a grouping that includes a common ancestor and all the descendants (living and extinct) of that ancestor. Using a phylogeny, it is easy to tell if a group of lineages forms a clade. Imagine clipping a single branch off the phylogeny — all of the organisms on that pruned branch make up a clade.”

See Clades and phylogenies and clades rotate = equivalent phylogenies.

Related articles

The Importance of Race and Ethnic Background in Biomedical Research and Clinical Practice

The New England Journal of Medicine, Vol. 348, p. 1170-1175, 2003

Esteban González Burchard, M.D., Elad Ziv, M.D., Natasha Coyle, Ph.D., Scarlett Lin Gomez, Ph.D., Hua Tang, Ph.D., Andrew J. Karter, Ph.D., Joanna L. Mountain, Ph.D., Eliseo J. Pérez-Stable, M.D., Dean Sheppard, M.D., and Neil Risch, Ph.D.

The Genomic Challenge to the Social Construction of Race

By Jiannbin Lee Shiao, Thomas Bode, Amber Beyer et al, Sociological Theory, Vol 30, Issue 2, 2012

Race in biology, genetics and cladistics. Wikipedia.

The Whole Side of It—An Interview with Neil Risch. By Jane Gitschier

 

Learning Standards

(see clades)

Egyptians, Genetics, Sociology and Race

From Nivenus, at Observation Deck:

When the cast of Exodus: Gods and Kings—Ridley Scott’s upcoming Biblical epic—was announced a lot of people made the complaint that it was overwhelmingly white, a move they decried as both inaccurate and racist. They were right. Unfortunately, in response a lot of people have peddled another historical (and racist) error: that the ancient Egyptians were black and that modern Egyptians are imposters…

…Cultures as different from one another (and Western Europe) as the Mongol Empire, northern India, Arabia, and Comanches have all been portrayed by white actors … because, again, the presumption is that a white actor is a blank slate within whom everyone can identify, including non-white people

…However, while the tendency usually is to whitewash historical peoples, the opposite also sometimes occurs. There is an increasing tendency I’ve noticed for some people, for example, to re-envision all of the ancient societies of the Old World as not simply non-white, but specifically “black.” Putting aside for a moment the fact that within Africa itself “black” is a largely meaningless term (there’s more genetic variety within Africa’s “black” population than the rest of the world combined), this is just simply false. The samurai were no more black than they were white. And neither were the ancient Egyptians.

That’s right, the ancient Egyptians weren’t black. They weren’t white either, mind you, but to presume that a culture has to be one or the other is to accept a racial dichotomy that white colonialists themselves invented for the purpose of sorting the world into “civilized” (white) and “savage” (colored) peoples. Most cultures in the world don’t really fit neatly into either category: are Latinos white or colored? The answer depends partially on who’s asking the question: most Latinos identify as white (both in the U.S. and Latin America) but most non-Latino Americans usually sort them as non-white.

The truth is that “white” is essentially a byword for “European” (sometimes northern European specifically) while “colored” basically just means everyone else. And these categories aren’t static or unchanging either. In 19th century Europe, various ethnic groups were sometimes sorted into “more” or “less” white groups. According to many British anthropologists, the Irish were “less white” than the English. According to the Nazis, Slavic-speaking peoples like Poles or Russians were “subhuman” non-Aryans. Today, virtually all of these groups are considered “equally” white (and Jews, who weren’t considered white at all, now often are).

This outdated way of talking about race was so prevalent and so dominant in academic circles that it’s been accepted as largely accurate, even by lots of non-white people. Instead of challenging the arbitrary lines in the sand 19th century racists drew up to sort people into those who were worthy of self-rule and those who weren’t, a lot of people have just flipped the idea on its head, arguing that the roots of all civilization are inherently “black” rather than “white,” as Eurocentric scholars claimed.

Which brings us to Egypt. For some reason or another—possibly because of the highly publicized discovery of Tutankhamun’s tomb in the 1920s, possibly because the Great Pyramid of Giza is one of the last remaining wonders of the ancient world—everyone wants to claim ancient Egypt for themselves….

What were the ancient Egyptians? Were they black or were they white?… Oddly, it’s occurred to relatively few people to look at how modern Egyptians think of themselves, because we have divorced ancient and modern Egypt in our minds as if they’re two completely unrelated cultures. …

…. what about how Egypt got invaded and conquered by a whole bunch of people, including the Arabs? Couldn’t that have impacted the Egyptians’ race? Well sure, that happened. Libyans, Nubians, Canaanites, Mesopotamians, Persians, Greeks, and Romans have all ruled Egypt at one point or another and the Arabs are the most recent bunch (not counting the Turks or the British). But the truth is that conquest only very rarely leads to a massive shift in the native population… genetic studies in Egypt back this up:

the genetic profile of modern Egyptians has been affected less than 15% by foreign admixture.

Egyptian hieroglyphics race

There’s also the fact that ancient Egyptians didn’t really perceive themselves as either “black” or “white.” Just look at the above painting from Pharaoh Seti I’s tomb. The top right group, with the palest skin are Libyans (Berbers), the next one over to the left are Nubians, followed by “Asiatics” (Mesopotamians).

The bottom central group are Egyptians. By their own perception Egyptians were neither particularly dark nor particularly pale, and given their xenophobic attitude towards outside cultures (which was fairly common for most ancient peoples) they would probably resent being sorted into either “race.”

So why does this matter? Why is it important that we acknowledge the Egyptians don’t fit into our constructed dichotomy of black vs. white, of European or African? Well, for one thing many modern Egyptians find it kind of offensive. Despite their modern self-identification as Arabs, most Egyptians still feel a strong claim to the historical legacy of their ancient forebears and find it pretty annoying when American scholars (and, black or white, it is mostly Americans) try to pigeonhole the pharaohs into one racial category or another for political purposes.

Secondly, it’s pretty clearly false as I’ve shown above. The ancient Egyptians were African, but that’s a pretty broad label, just like the word “Asian” includes within its meaning Turks, Indians, Samoyeds, Han Chinese, and Malays. There’s a lot of similarity between Egyptians and Nubians, that’s true. There’s also a lot of resemblance between Egyptians and Palestinians. They don’t fit neatly into one super-category or the other, not when you peel away the labels and look at the actual facts.

Egyptians Aren’t White… But They Aren’t Black Either

Also see Genetic variation, classification and race