[D66] [ANTHRO-L] How Europeans evolved white skin

[Henk Vreekamp]

Democs,
Het zit’em in de lucht of ‘t is het stille jaargetij – maar zelfs antropologen zijn weer es bezig met de (direct van racisme / etnocentrisme afgeleide) kwestie van de huidskleur. Overigens, al sinds begin 20e eeuw (Frans Boas e.a.) zijn de leidende menswetenschappers het eens over het feit dat er bij mensen slechts sprake is van één ras. De genetische verschillen binnen de mensheid zijn te gering, geografisch bepaald, om te spreken van meer rassen en rasverschillen.
Kennelijk bestaat er een universele behoefte zich te onderscheiden, bijv. op sociale klasse (Pierre Bourdieu). De lager opgeleiden worden bijv. door de gegoede klasse immer geassocieerd met defecte bekwaamheden. Dat de hoger opgeleiden ook zo hun defecten hebben hoor je nooit, zoals het recente CBSfeit  dat de hogeren 83% van de gezondheidssekteaanhangers vormen.
Je zou kunnen zeggen dat raspraatjes onderdeel vormen van ‘’grof onderscheid daden”. Een helder overzicht van rastheorieën is het boek “The history of white people” (2010) van Nell Irvin Painter, een oud-hoogleraar Princeton. O ja – dit voor onze verschil-liefhebbers – ze heeft een donkere huidskleur. Ze stond ook een jaar op de New York Times Bestsellerlijst. Als het niet meer te koop is, staat het misschien ergens in een Amsterdamse bibliotheek.
hv,u
From: Wilsnack, Richard 
Sent: Saturday, February 10, 2018 10:03 PM
To: ANTHRO-L at LISTSERV.BUFFALO.EDU 
Subject: Re: [ANTHRO-L] How Europeans evolved white skin

 

From: Anthro-L [mailto:Anthro-l at listserv.buffalo.edu] On Behalf Of Andrew Petto
Sent: Friday, February 09, 2018 10:11 PM
To: ANTHRO-L at LISTSERV.BUFFALO.EDU
Subject: Re: [ANTHRO-L] How Europeans evolved white skin

 

<snip> As Dale points out, humans are subject to the same sorts of geographic trends as other mammals; Bergman's and Allen's rules, for example, and intensity of UV-B blocking integumentary structures. But, we are also subject to the random, accidental variations that pop up in populations. If we take malaria as an example, we have 3 major changes to hemoglobin to make it more resistant to digestion from plasmodium parasites. Why 3, and not one? Sure, part of it is that the parasites themselves are different. But, we also know that G6PD is in North Africa, and Hb-S is in the erstwhile "fertile crescent" and into the Indian subcontinent. So, clearly these genes are shared by migrants or merchants or soldiers, or whatever. BUT, they are 3 different strategies to solve the same problem (and yes, I am lumping all the Thalassemias together for the sake of argument). And in some places, the population has more than one of these variants.

However, there do not seem to be any hemoglobin variants for resistance to malaria in indigenous populations of the New World (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3182497/). 

So, we could ask a similar question about the hemoglobin variants that confer malaria resistance that we do for the pigmentation changes in European populations...how can we explain why the responses in one geographic population are different from those in another? Could be lots of reasons, and the selective pressure of malaria is only one among them. <snip>

 

Anj’s comment on multiple possible genetic responses to similar environmental selection factors reminded me of the research on lactose tolerance among the Maasai and some other groups in Africa, a continent where such tolerance is not as common as in Europe (nor as uncommon as in East Asia):

As summarized by Ann Gibbons, in "There's More Than One Way to Have Your Milk and Drink It, Too," Science  Vol. 314, Issue 5806 (15 December 2006), p. 1672:

“The adage that milk does a body good may be true for American celebrities wearing milk mustaches in ad campaigns: Many Americans and northern Europeans descend from cattle herders and carry an ancient mutation that allows them to tolerate milk at any age. But milk gives cramps and diarrhea to roughly half the world's adults, especially in Asia and West Africa. That's why lactose tolerance has been held up as a classic example of human evolution, in which some people inherited the trait to digest milk, and some didn't. Now, an international team reports a revealing twist on this evolutionary story. In this week's issue of Nature Genetics, researchers describe three new genetic variants that arose independently in groups of Africans; each variant allows carriers to drink milk and eat dairy products as adults. The study shows that lactose tolerance evolved more than once in response to culture, says team leader Sarah Tishkoff of the University of Maryland, College Park. It's also an elegant example of how evolution can find several solutions to the same problem, especially in the face of strong selection, says molecular anthropologist Kenneth Weiss of Pennsylvania State University in State College. ‘There is not just one way to tolerate milk but several ways,’ he says. ‘It's very nice work because it shows that evolution isn't just about picking one gene and driving it.’ ”

Richard W. Wilsnack 

richard.wilsnack at med.und.edu

 

 

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