Race, Ethnicity, Culture, and Epigenetics

Interesting findings.

If we ignore the PC-oriented nonsense about “social constructs” as well as the confusion about ethnic identification and ancestry, there are some interesting points in this article.

Excerpts, emphasis added:

These researchers report that they have identified signatures of ethnicity in the genome that appear to reflect an ethnic group’s shared culture and environment, rather than their common genetic ancestry.

“We found that both self-identified ethnicity and genetically determined ancestry were each significantly associated with methylation levels at 916 and 194 CpGs, respectively, and that shared genomic ancestry accounted for a median of 75.7% of the variance in methylation associated with ethnicity,” wrote the article’s authors. “There was a significant enrichment…of ethnicity-associated sites amongst loci previously associated environmental exposures, particularly maternal smoking during pregnancy.”

Roughly one-quarter of the epigenetic difference between the two ethnic subgroups could not be accounted for by differences in the children’s genetic ancestry. This difference, the authors suggested, could reflect a biological stamp made by the different experiences, practices, and environmental exposures distinct to the two ethnic subgroups.

It demonstrates in a whole new way that race combines both genetics and environment.

Studies by the Burchard group and others have found that using genetic ancestry rather than ethnic self-identification significantly improves diagnostic accuracy for certain diseases.

But the new data showing that a large fraction of epigenetic signatures of ethnicity reflect something other than ancestry suggests that abandoning the idea of race and ethnicity altogether could sacrifice a lot of valuable information about the drivers of differences in health and disease between different communities.

The nonsense about distinguishing more accurate “genetic ancestry” from less accurate “ethnic self-identification” fails the smell test since the Risch lab a while back showed near-perfect correspondence between identify and ancestry.  True enough, there is a social component to these things, since humans give simple labels to complex categories.  Thus, both Colin Powell and a pure-bred Nigerian would both identify as “Black” although there is quite a difference in their ancestry.  But that does not mean that ethnicity/race and genetic ancestry are different things; it instead means that human beliefs about ethnicity/race may not always be the same as genetic ancestry.

In any case, the main point here is that about 75% of the epigenetic differences between “ethnic sub-groups” are associated with genetic ancestry and cultural/experience differences associated with ethnicity accounted for the other 25%.  

Therefore, there is a two-way interaction between the biological and the social/cultural. Biological differences inform the foundation of ethnic/racial identity (influenced socially by human beliefs about these groups), and cultural differences stemming from these identities can feed back and affect the biology.

“Back in the day” Ursus Major, affiliated with the EASU, talked about a “Race-Culture.”  He was more right then he knew.

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