Personalized DNA tests likely to provide further evidence of human inter-connectedness

Great NPR piece here on how new technologies in personalized DNA testing have the potential to broadly expand our understanding of human relatedness.

I am particularly interested in the idea that these tests further reinforce previous research showing just how much of our gene pool is shared globally rather than locally. While these tests are aimed at understanding relatedness — and often reveal that the “regional purity” of a person’s background is fictive and not grounded in biological reality — they also have the potential to tell us about human variation. We are all related means that there is a lot of gene flow between populations, such that your regional ancestry might not profoundly dictate your genetic make-up. But this we are all related quality of human population genetics does not imply that we don’t maintain genetic variation. It is possible that there is a lot of genetic variation within populations, and that these tests might begin to reveal that variation in a larger sample size. For people like me who are interested in human genetic variation, this is exciting.

It is also interesting how these kinds of commercial tests have the potential to finally illuminate the amount of reproductive cuckoldry that exists in human populations. Previous studies (for example, Larmuseau et al. 2013) have shown that in populations with clear genealogical history, rates of extra-pair paternity (EPP) are very low (1-2% per generation). I am curious whether these EPP rate estimates change as more and more genetic data is collected from a broader human population sample.

I guess an important caveat here is that these commercially-produced data sets are always going to be a biased sample. Only affluent people can afford to have their ancestry probed by genetic testing, so inevitably the sampled population will not be representative of the overall human population. Still, the results from this biased sample could improve our understanding of historical human population structure.