Did FoxP2 introgress into Neandertals?
It sure looks that way to me. Let’s consider the evidence: FoxP2 recently fixed in humans. According to Enard et al. (2002:871): Under a model of a randomly mating population of constant size, the most likely date since the fixation of the beneficial allele is 0, with approximate 95% confidence intervals of 0 and 120,000 years. Now, Enard et al. (2002) noted that human populations have grown over time, and that they are not randomly mating, so that this date estimate might be too recent. Allowing for population growth since “10,000–100,000 years ago,” they asserted that fixation of FoxP2 must have happened “during the last 200,000 years of human history.” But this is not quite accurate. Unlike genetic drift, positive selection can and often does fix genes rapidly in a growing population. It simply doesn’t matter that the human population has been rapidly growing: FoxP2 may still have just become fixed yesterday. Last year, Green and colleagues (2006) considered that the Neandertal-mod
