Title: Our genetic legacy: Neanderthal genes or predictable mutations?

Abstract:

It is widely accepted that non-African humans share about 2% of their genome with Neanderthals and that inter-breeding occurred between several archaic lineages.  However, mutation rate may vary between human populations and appears to be higher in Africa than elsewhere, possibly because mutation rate and heterozygosity are linked such that mutation rate slowed as humans lost diversity ‘out of Africa’.  If so, an alternative explanation of the data becomes possible, based on non-Africans diverging less from our common ancestor. I have tested a series of predictions aimed at distinguishing mutation slowdown from introgression. In every instance mutation slowdown fits better, often to the exclusion of inter-breeding.  While some inter-breeding probably did occur, the resulting legacy was small or even negligible.  On the positive side, my analyses suggest that mutations may be more predictable than is currently assumed.