DNA home truth

22 Mar 2018

I was looking through a press release at https://phys.org/print440836060.html ... which is about the genomes of five late Neanderthals that lived between 39,000 and 47,000 years ago. They contributed DNA to modern human ancestors which is okay - so far. We are then told the Neanderthals overlapped with the arrival of modern human, which is partly based on the fact that modern humans have a small amount of Neanderthal DNA (so they must have overlapped, must they not?). Did they? Did late Neanderthals pass on their genes to modern humans by mating with them - which is the nub of the issue. If they died out prior to the arrival on the scene of modern humans one would have to think in terms of a different way of passing on their genes - which is being ignored. The elephant in the room is that the period between 30 and 40,000 years ago is a massive C14 plateau event (which affects the dating of both Neanderthals and modern humans). In other words, there is a lot of guesswork going on. This is not of course for public consumption. We have to fix our eyes on the genetic inheritence. One then has to wonder why we should do that as the most interesting aspect of this paper is that they admit there is no trace of modern human genes in late Neanderthals - anywhere. They are forced to add the caveat - it may be that gene flow was unidirectional, from Neanderthals to modern humans (but not the reverse). That is one way of getting out of jail I suppose but who is going to fall for it? If Neanderthals passed some of their genes on to modern humans but the latter did not pass any genetic material in the other direction this can only mean the story is a little more complicated than anthropologists are willing to admit. There was a bottleneck. Neanderthals died out - or nearly so. The survivors passed their genes on to modern humans. Modern humans are either the descendants of the few Neanderthal survivors or modern humans are a new group of people that entered Europe after the demise of the Neanderthals (or the vast majority of them).