Studies of modern human admixture, such as those showing the admixture of European decent males and Indigineous South American females would clearly give a modern example of exactly how this process happens.

Both theories are likely correct. One theory doesn’t logically make the other impossible. The two theories actually bolster each other – showing how modern humans migrated.

Other human variation is likely to show the same thing as groups migrating out of Africa into Asia following herd migrations were trapped into isolated pockets of temperate zones. When the ranges open back up and more modern humans met with thes isolated pockets the admixture of modern males with the isolated groups females should be the expect model of interaction.

“It was Leo Slizard who said…”

Googling the web, I cannot find this precise quote attributed to anybody. Certainly not to Leo Szilard (not Slizard, a mutation which perhaps arises from conflation with Henry Tizard). The nearest I can come up with is indeed Arthur Schopenhauer:

“All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident. “

It was Leo Slizard who said there are three stages of truth in science.

1)It is not true
2)It could be true but it doesn’t matter
3)I knew it all along

I like the concept but it was actually Arthur Schopenhauer not Leo Szilard

none the less the rest of your discussion is on target

I see the scenario like this. A big nosed, heavy browed, Neanderthal female may be OK as a back-of-a-cave job but the pretty slim sapiens females newly out of Africa were more of a turn on to a Neanderthal male. Not that the Neanderthal missus would allow the new strumpet a place in her cave, so it was always a passing fling, then back to her own. And no attraction of sapiens males to butch Neanderthal women.

Good points.

As for this:

Of course, this suggests that while modern humans and Neanderthals might have interbred in the middle east 50,000 or more years ago they didn’t continue to doing so after that time, even though they would have had ample opportunity to do so in Europe for another 20,000 years. Something about that doesn’t make sense.

Two possibilities occur to me to explain this lack of further increase in Neanderthal origin genes in Europeans who lived side by side with them for a longer period of time than the other racial genomes sampled in this study.

1) The ancestors of people who became distinctly Europeans had already taken in all the Neanderthal genes that were helpful; the rest were harmful or neutral and there wasn’t enough interbreeding for neutral genes to remain fixed in the European genome and thus the additional rare mattings with Neanderthals which occurred didn’t add a higher percentage of Neanderthal genes which fixated (stuck around through subsequent human generations); or

2) After the earlier introgression of Neanderthal genes somewhere around Israel, humans e.g. got enough of a brain boost through additional Neanderthal coding for post birth brain enlargement and maybe an enhanced visual cortex and memory such that humans were then on all accounts much smarter than Neanderthal and able to defeat and overawe them with ease, thus now almost completely effectively warding larger Neanderthal males off from mate snatching or raping of human females for example. And making them then really taboo for human males. Note this isn’t incompatible with the apparent fact that Neanderthals had less developed voice boxes and elaborate language ability and smaller foreheads. Human brains before any introgression of Neanderthal genes may well have been more complex with larger language areas and logical planning frontal cortex. Similarly all the useful and not also more harmful Neanderthal non brain genes for dealing with cold weather may also have already fixated during previously colder times in the Middle East when humans interbred a little with Neanderthals, before humans moved up into Europe as it started getting warmer.

Please note the distrust and suspicion given by liberals in general to Monsanto and genetically engineered foods. Even though it is a scientific breakthrough that enormously lowered the energy costs for farmers by creating no till farming with absolutely no negative side effects. The latest chapter was just well covered by Carl Zimmer here at Discover blogs. I have followed every article about Monsanto and it’s long list of round-up ready seeds for years and I have yet to read one scrap of news that is positive. I’m sure Monsanto as a profit motivated company has it’s faults, but the product itself has none, it has lowered farmings costs, increased productivity, saved topsoil erosion, and made our food considerably cheaper.

HSS not inseminating HSN females. Impossible.

As to Freddie Flintoff, you are not a dimbulb, you are merely witnessing the mutilation of science by political correctness.

The contemporary political scene needs to get used to genetic differences between humans as a scientific fact, not mere retrospectively, as when talking about the movement of ancient tribes, but also prospectively, as germ line genetic engineering comes on line.

The most counter-productive thing the “left” could do would be to put their heads in the sand or attack science.

Two small populations coexisting in a space the size of Europe might translate into a small probability of sufficient chance encounters, even over a long time scale.

You’re right. I initially thought the Oceanic subject was from Melanesia (which would make it part Austronesian and, ultimately, part East Asian). But it’s a Papuan from the center of Papua/New Guinea.

This would suggest that Neanderthal admixture happened in southwest Asia when modern humans first began to spread out of Africa. But, as you point out, why would admixture happen there but not in Europe, where the two populations co-existed for a much longer time? If there had been subsequent admixture in Europe, we would see more Neanderthal admixture in present-day Europeans, but we don’t.

The only possibility I can imagine is that Neanderthal genes entered the modern human gene pool indirectly, via an intermediate population in the Middle East that already had Neanderthal admixture (because of prolonged contact) but was essentially modern human or close to modern human. There would have been no subsequent admixture in Europe because there was no intermediate population, and the behavioral distance between the two groups would have been just too great to facilitate admixture.

Any other ideas?

As I understand it the problem with this suggestion is that it conflicts with the current view, based on archaeological evidence, that New Guinea (and Australia, they were connected by a land bridge then) was populated by modern humans about 45,000 years ago, and that this original population was never replaced by more recent arrivals. That is, while the ancestors of the French genome donor (and maybe the Chinese donor, who knows?) probably lived in the same general area as Neanderthals until 30,000 years ago, the ancestors of the New Guinea donor are thought to have left that area at least 15,000 years earlier, a fact which is almost certainly why a New Guinea genome was included in the comparison. The fact that the New Guinea genome is as closely related to Neanderthals as the other Eurasians is probably why a lot of articles about this suggest the date when the interbreeding occurred is 45,000 to XX,000 years ago.

Of course, this suggests that while modern humans and Neanderthals might have interbred in the middle east 50,000 or more years ago they didn’t continue to doing so after that time, even though they would have had ample opportunity to do so in Europe for another 20,000 years. Something about that doesn’t make sense.

It’s not over yet.