Both Denisovans and Neanderthals mated with the ancestors of modern humans, who emerged from Africa about 60,000 years ago.
Interbred with Africans before or after 60 000 years ago? If before, would it not suggest that the Africans came from elsewhere?
I've always been very upfront about the fact that I don't like the Neanderthal/Sapiens interbreeding hypothesis at all. It has become a bit of a trend, recently, but to paraphrase Al Gore, "The science is far from settled", as far as I can see. (I rather suspect that the 'interbreeding' theory is popular amongst anthropologists, because it is sensationalist and therefore good for generating grants, and because it fits in with the 'we are all the same' notion of leftist and collectivists).
The thing is that Neanderthals and humans DID have a common ancestor. I'm of the opinion that whatever interbreeding took place happened in Africa between pre-Neanderthals and pre-humans when they were genetically much closer to each other, long before Neanderthals dispersed into the rest of the world to become Neanderthals proper, and pre-humans developed into Sapiens proper.
It could even be that at that stage, (when interbreeding may have taken place) the pre-Neanderthals were intellectually superior to pre-humans. They did, after all, manage to populate other parts of the world, whereas pre-humans stayed put in Africa.
But by the time humans left Africa more than a 250,000 years later, there was no comparison (in terms of intelligence, technical skill) anymore and we had two properly distinct species, incapable of interbreeding.
"Hopefully, everyone will become more cautious before invoking hybridisation, and start taking into account that ancient populations differed from each other probably as much as modern populations do.”
Whereof one cannot speak, thereof one must be silent.
I rather suspect that the 'interbreeding' theory is popular amongst anthropologists, because it is sensationalist and therefore good for generating grants, and because it fits in with the 'we are all the same' notion of leftist and collectivists.
I cannot agree more.
It also seems to me that the science is not unsettled only in relation to the cross-breeding, but also in many other respects when it comes to our ancestors. This is based on the regularity with which previous classifications and dates are revised. I appreciate that our ancestory may present difficulties, but often conclusions are presented with a brash conviction later proved to be unwarranted.
I lately tend to suspect that there was a much wider distribution of humans and ancestors than projected by the Out of Africa scenario. Perhaps it happened, but not exclusively to Africa. This would imply that there was a much wider, earlier movement of people all over the world and that the situation remained fluid for a long time. Assuming that we all descend from a single cell, one perhaps has to assume an intial origin and an exodus from somewhere, but much, much earlier than the popular Africa one.
The fact that I am considered an adult is both terrifying and hillarious
Reich’s work as a leader of prehistoric population studies includes the discovery that all people of non-African descent carry small amounts of Neanderthal DNA, showing that Homo sapiens – at one stage – must have interbred with this long-dead species of ancient humans. Reich was also involved in uncovering the existence of Denisovans, a previously unknown species of ancient humans, using DNA found in fossil scraps in a Siberian cave.
In addition, he has discovered that 5,000 years ago northern Europe was overrun by invaders from central Asia, a migration of profound importance – for those newcomers became the first people of the British Isles.
The ingrained notion – that there has only ever been one species of human being, Homo sapiens – is a latterday fiction born of our own self-important view of ourselves. Think instead of the bar scene from Star Wars with all those various people playing and drinking, says the Israeli palaeontologist Yoel Rak. That gives a far better flavour of our evolutionary past.
Instead of a tree, a better metaphor would be a trellis, branching and remixing far back into the past, says Reich, whose work indicates that the idea of race is a very fluid, ephemeral concept. However, he is adamant that it is a very real one and takes issue with those geneticists who argue that there are no substantial differences in traits between populations.
“This is a strategy that we scientists can no longer afford and that in fact is positively harmful,” he argues. Plenty of traits show differences between populations: skin colour, susceptibility to disease, the ability to breath at high altitudes and the ability to digest starch. More to the point, uncovering these differences is only just beginning. Many more will be discovered over the decades, Reich believes. Crucially, we need to be able to debate the implications of their presence at varying levels in different populations. That is not happening at present and that has dangerous implications.