Tuesday, September 22, 2009

DNA and Self

Can members of tribes and other ethnic/cultural groups -- who believe they are completely distinct peoples -- be demonstrated to be biologically different? Nope, not even close. That's the result of a study published in BMC Genetics earlier this month.

Evelyn Heyer and an international team of researchers set out to answer this by studying the adjacent – and culturally very different – Tajik and Turkic speakers along the Silk Road of Central Asia. Here is a vivid example of culturally divergent groups living in close proximity: the Turks are nomadic herders and clan based. The Tajiks are farmers and married Tajik women live with their husbands' family. Their languages are distinct and of different derivation.

The two consider themselves closed societies, and members of both groups are said to rarely leave their clan or village. In a post this month at "the spittoon," the blog for direct-to-consumer DNA testers 23andme, Anne Holden wrote:

...the researchers collected both maternally inherited mitochondrial DNA and paternally inherited Y chromosome DNA from more than 1,000 individuals spanning 24 Turkic and Tajik populations.

What they found was that these two ethnic groups weren’t so different after all.

Genetically, the Tajiks and the Turks were virtually indistinguishable. The authors found the overall level of genetic diversity between the two groups to be less than 1% overall — so small that there was a greater amount of diversity within each group than between the two. (emphasis mine)

How do we explain those results to the study participants? Is this something they want to know / will believe / will create a change? And what are the broader implications? According to the provocative blogging scholar Dienekes Pontikos
...a better angle on the topic would be to observe how prevalent ethnic differences are, if they can exist even among populations that are genetically non-differentiated...humans happily self-segregate themselves along ethnic lines, even when there are no underlying genetic differences.
What does THAT imply? If nothing else, Pontikos -- whose work is cited in publications like Journal of Genetic Genealogy and American Journal of Physical Anthropology -- doesn't shy away from the big questions. Let the discussion continue! I recommend the Center for Genetics and Society, who write
Genetic, reproductive and biomedical technologies have the power to promote or undermine individual well-being and public health, create private fortunes or advance the public interest, and foster or threaten a just and fair society.

Used appropriately, many human biotechnologies hold great potential for treating disease and alleviating suffering. But these same tools can also be abused, either deliberately, inadvertently, or because of our inattention and inaction.

These are heady times: let's think it through.

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