Posted: Oct 07, 2011 7:00 pm
Tyrannical wrote:http://johnhawks.net/weblog/reviews/denisova/foxp2-denisova-humanlike-2011.html
The Denisova fossil also has the modern human version of foxp2, just like neanderthal man does. That makes the origin of foxp2 prior to 250k -400k years ago.
From the original paper: "The phalanx was found in layer 11, which has been dated to 50,000 to 30,000 years ago." That sample is not much older than the samples of the neandertal genome that were sequenced, if at all.
The paper says that the Denisovans are a sister group to Neandertals (and thus to sapiens) "Nevertheless, the picture that emerges from analysis of the nuclear genome is one where the Denisova population is a sister group to Neanderthals."
One way to have the same FOXP2 is to inherit it from a common ancestor. Humans and neandertals have a common ancestor about 800,000 years ago. Another way is for gene flow much more recently. Since it has now been shown that there was gene flow between neandertals and sapiens, there may have also been gene flow between Denisovans and sapiens. In fact, the paper does note that Denisovans contributed to the genes of Melanesians. So it is possible that FOXP2 is less than 100,000 years old and was passed by sapiens to both neandertals and Denisovans.
By the timeline of Reich and colleagues [1], that would be prior to 250,000-400,000 years ago.
I don't see a timeline like that in the Reich et al. paper.