Thursday, 7 March 2013

speculation and ancestral genetics

A BBC News article published today offers its readers an interesting counter-argument to the burgeoning array of private enterprises offering potential customers a genetic recounting of their ancestry.

"The DNA ancestry tests appeal to our interest in our family trees. However, our DNA is not the story of our family tree. It is a mosaic of genetic sequences that have been inherited via many different ancestors. With every generation you (nearly) double your number of ancestors because every individual has two parents – going back just 10 generations (200-300 years) you are likely to have around a thousand ancestors. We don’t have to look back very far in time before we each have more ancestors than we have sections of DNA, and this means we have ancestors from whom we have inherited no DNA." - from Sense About Genetic Ancestry Testing

What we might understand as an infinite regression conundrum in ancestry testing is only one issue in this discussion. As Dana Fullwiley points out in a 2008 article for Genewatch, margins of error in genetic testing technologies can lead to the bizarre possibility of "artificial ancestry", wherein an erroneous ancestral claim can be made about an individual. This brings to light the obscure tension between what we consider to be the reality of our origins are epistemologically, the tools we adopt to determine it, and the inherently speculative nature of ancestry testing.

"Genetic ancestry testing presents a simplified view of the world where everyone belongs to a group with a label, such as ‘Viking’ or ‘Zulu’. But people’s genetics don’t reflect discrete groups. Even strong cultural boundaries, such as between the Germanic and Romance language groups in Europe, do not have very noticeable genetic differences. The more remote and less-populated parts of the UK, such as the Scottish Highlands, do have some genetic differences from the bulk of the population, but they are not big. There is no such thing as a ‘Scottish gene’. Instead groups show a story of gradual genetic change and mixing." - from Sense About Genetic Ancestry Testing

We might aso think about the incongruence of claims made by groups of people, and the claims produced by the ancestral genetic testing that is undertaken on them. (check out Sharp and Foster's 2002 article where they argue that in genetic research dealing with "populations of which individual donors are members  means that all  members of those populations may be affected by research findings, including those who did not consent to or take part in the resource” [p. 847]). A challenge of an individual or their collective's world view raises a host of ethical issues.

I've also been thinking quite a lot recently about the renewal of classificatory boundaries of identity through genetic testing. The quote above invokes concepts akin to "genetic drift" and "admixture". I wonder how molecular science is reconstituting specifically social, cultural and/or religious groupings through this language. That's not to say that the science is inherently "wrong". I don't know that research in this area can be right or wrong when it's a matter as speculative as ancestry. It's simply a matter of recognising that who we choose to be is determined by so many different things, and an genetic ancestry tool is one such thing.

Amazing stuff.

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