I can't wait until we have some more success with ancient DNA from the sites in South Africa where I'm working. I think there's a good chance of it in the next decade.
It seems to me that a few decades ago, anthropologists believed that Homo sapiens was a descendant of Neanderthals.
This hypothesis was abandoned, but I haven't been able to find any papers that clearly show that Homo sapiens was not a descendant of Neanderthals.
Yet, during the supposed period of their cohabitation, skeletons and DNA were found with traits shared by each species. Wouldn't this show that Neanderthals were evolving into Homo sapiens?
For how can we explain why Neanderthals, who lived for several hundred thousand years on the Eurasian continent, would have disappeared in less than 10,000 years?
On the other hand, I can't understand what it clearly means that we have between 1 and 4% of the Neanderthal genome in Europe.
I'm no geneticist, but I believe one can spot the difference between a population evolving in almost total isolation from others for a long period of time, and a population composed of two( or more) divergent lineages that evolved separately for long periods of time.
As you say, humans with higher Neanderthal DNA have been found from around 50,000 or so years ago, but those percentages aren't found in any modern humans. It seems that humans were much more successful at adapting to the environment and outcompeting Neanderthals, so only a tiny portion of modern human DNA is descended from Neanderthals. A good analogy would be how most Puerto Ricans are of dominantly mixed European-African descent, with the native Taino population comprising a smaller portion. The natives seemed to have largely been killed or wiped out by introduced diseases. A population with certain advantages can virtually lead to the wiping out of another one, even if a small part of the wiped out people's DNA survives in the advantaged group.
The postcontact Caribbean is an interesting example that provides one idea of how these fractions of mixture might happen in the descendants of multiple populations. An important aspect with the Neanderthals and early modern humans is the very low population densities, especially during the early contact period in Europe. None of the earliest European people had much contribution to today's gene pool; not Neanderthals, nor the early modern humans.
Yes, expansions fueled by a certain tool( like a particular blade) or even greater social cohesion could lead to one group of humans simply developing larger populations, so even if the smaller groups were just incorporated into the expanding group peacefully(which probably does not reflect the entire picture of how their interactions went), the DNA fraction of the hunter-gatherer group would remain low. This is so even before one takes into account the rise of agriculture, which exacerbated the advantages of a population with that toolkit.
Maybe we will find some of these mysterious ancestors in the future. Based on this article, I have decided to believe in ghosts too.
I can't wait until we have some more success with ancient DNA from the sites in South Africa where I'm working. I think there's a good chance of it in the next decade.
It seems to me that a few decades ago, anthropologists believed that Homo sapiens was a descendant of Neanderthals.
This hypothesis was abandoned, but I haven't been able to find any papers that clearly show that Homo sapiens was not a descendant of Neanderthals.
Yet, during the supposed period of their cohabitation, skeletons and DNA were found with traits shared by each species. Wouldn't this show that Neanderthals were evolving into Homo sapiens?
For how can we explain why Neanderthals, who lived for several hundred thousand years on the Eurasian continent, would have disappeared in less than 10,000 years?
On the other hand, I can't understand what it clearly means that we have between 1 and 4% of the Neanderthal genome in Europe.
Those are some great questions! I’ll come back to them later for more comprehensive answers.
I'm no geneticist, but I believe one can spot the difference between a population evolving in almost total isolation from others for a long period of time, and a population composed of two( or more) divergent lineages that evolved separately for long periods of time.
As you say, humans with higher Neanderthal DNA have been found from around 50,000 or so years ago, but those percentages aren't found in any modern humans. It seems that humans were much more successful at adapting to the environment and outcompeting Neanderthals, so only a tiny portion of modern human DNA is descended from Neanderthals. A good analogy would be how most Puerto Ricans are of dominantly mixed European-African descent, with the native Taino population comprising a smaller portion. The natives seemed to have largely been killed or wiped out by introduced diseases. A population with certain advantages can virtually lead to the wiping out of another one, even if a small part of the wiped out people's DNA survives in the advantaged group.
The postcontact Caribbean is an interesting example that provides one idea of how these fractions of mixture might happen in the descendants of multiple populations. An important aspect with the Neanderthals and early modern humans is the very low population densities, especially during the early contact period in Europe. None of the earliest European people had much contribution to today's gene pool; not Neanderthals, nor the early modern humans.
Yes, expansions fueled by a certain tool( like a particular blade) or even greater social cohesion could lead to one group of humans simply developing larger populations, so even if the smaller groups were just incorporated into the expanding group peacefully(which probably does not reflect the entire picture of how their interactions went), the DNA fraction of the hunter-gatherer group would remain low. This is so even before one takes into account the rise of agriculture, which exacerbated the advantages of a population with that toolkit.