Wednesday, November 02, 2011

Denisova Update

John Hawks does not think that the recent data from the paper by Skoglund and Jakobsson holds up under scrutiny. He cites striking discrepancies between the analysis presented by these two with a paper that came out by Reich et al. (http://dx.doi.org/10.1016/j.ajhg.2011.09.005) called “Denisova admixture and the first modern human dispersals into southeast Asia and oceania.” Their salient finding is that there were very few Denisovan markers in mainland Asian populations.

Hawks suggests that the reason the two papers differ so greatly is that in the paper by Skoglund and Jakobsson, the analysis is picking up only slight differences in gene frequencies between populations, and that, while there is hybridization and migration into the area by Denisovans, it is small in amount. He writes:
We aren't very far from a more definitive answer of this question, as the data continue to accumulate every day. What I find interesting is the way that models can generate these 1% differences in ancestry proportions, depending on sampling and the pattern of migration assumed to have happened in the past. Two estimates that differ by less than a percent are not really different. This paper provides the suggestion of a more widespread Denisovan legacy, and I accept that as a possibility.
It is clear that there was some interbreeding between these populations. How much remains to be seen.

Hat tip to Paul Pavao.
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