AFAIK, Aborigines never performed appendectomies using sharp rocks – that was me being erm rhetorical

Apart from the Noongar, they did perform fairly comprehensive male circumcision using sharp rocks though. Ouch.

One of the things that interests me is that in the whole of Australia, the Noongar were the only people who did not practise male circumcision, and they resisted all attempts by neighbouring people to convert them to the practice. Question is why. There is evidence that the south west of Australia, Noongar country, was inhabited pretty early after entry of humans into Australia, which is not necessarily what you would expect, because it is far distant from possible entry points. Anyway, that’s tangential and irrelevant.

come now, that’s just a rhetorical stab. a lot of scientific hypotheses differ from pure speculation only insofar as you think it might be true or not, evidence (or lack of) be damned.

“the first signs of modern human genius as we recognize it today occurred in Europe” – Remind me again of the incomparably greater detail with which human anatomy was depicted in the >5,000 year younger cave paintings in France than in the rock art in Australia, would you Dave? Put yourself in my place – I’m in outback Australia 40,000 years ago, and I develop appendicitis. What do I need, some sensitive genius painting realistic depictions of animals, or some Aboriginal guy with a tool kit of very sharp rocks and a wall chart depicting the internal organs of humans?

In any case, this is not a pissing contest between Europe and Australia – the point really is that by 40,000 years ago, cave and rock art were already highly developed in both continents on opposite sides of the world, from much earlier starting points that already revealed behavioural modernity and symbolic thought. I look at that and see progression over a long period of time, not some rapid cultural explosion. What encourages belief in the great leap forward is absence of evidence, which is increasingly no longer absent.

There could be something in the latest Caspari paper to explain some sudden cultural leap, but I don’t have access.

To associate that with Neanderthal introgression is pure speculation, as is pale complexion and greater brain power, and the evidence is looking weak or non-existent. The question is then well what did we get from them that was advantageous, if anything? I think we want some pretty hard evidence about this, not pleasing speculation to ponder, when such evidence as there is suggests that there appears to be nothing real in it so far.

“There’s a recent hypothesis that rather neatly explains the “great leap forward.”
Grandparents. ”

That’s actually a fairly old argument, although, admittedly, it was rather qualitative and the new work improves on that. Longevity fosters longevity, since it reduces childhood and teenage mortality through experience such as knowledge of medicine and climatic fluctuations, and promotes risk-aversion (via painful memories of loved ones lost), among other reasons.

@ dave chamberlin:

I generally agree with your sentiment, but I think the “useful Neanderthal gene introgression” was of much longer-duration and wider spatial scope. In reality, AMHs were able to leave Africa ~120,000 – 130,000 years ago, but the apparent quantum leap did not take place until ~40,000 – 50,000 years ago. So, there was plenty time and space for admixture within N and NE Africa, the Levant, and later the wider West Asia and the Indian subcontinent.

Also, I believe admixture outside the immediate Near East was with more generalist Heidelbergensis-like people, not with highly-specialized Neanderthals.

Finally, substantial gene flow between Europe, West Asia, and North Africa until about ~300,000 years ago appear likely based both on climate and fossil studies. As such, North Africans likely had “benefited” from admixture even before AMHs arose (and vice versa).

Unfortunately, many Australian rock art sites are not well curated or even particularly well documented (there are really a lot of them, many in very remote locations). Locations are also kept secret to try to avoid vandalism, which is distressingly all too common.

Grandparents.

The article is a puff piece from the Telegraph that mentions an article in Scientific American.

http://www.telegraph.co.uk/science/science-news/8647686/Few-grandparents-until-30000-years-ago.html

This moves the question from “intellectual leap forward” to “longevity,” an entirely different issue. Unfortunately, since it’s from the Telegraph they don’t give a pointer to the actual article. At first blush though, the science and the inference seem sound.

I could be misrepresenting the research, but I recall “The 10,000 Year Explosion” saying that Africans did probably also have Neandertal genes that filtered their way back and underwent selection.

1) the few pigment genes known are different. probably functionally similar, but not the same as the european ones around today (also, loss of function toward depigmentation isn’t that hard).

2) the immune stuff is very new, and not even published. so don’t stand on that too much.

3) the idea of introgression and picking up locally favorable alleles seems plausible.

4) last i checked microcephalin was not introgressed from european neandertals. the neandertals had a different variant.

anyway, it’s a unsettled field. kind of hard to say anything stupid since so little is known with solidity IMO.

The great leap forward was not real.

http://www.youtube.com/watch?v=C2cMG33mWVY&ob=av3e

FWIW, I think the question may be the exact opposite of the “no smoking gun” hypothesis offered.

Anyway, why does it need to be the same reason? Migrations would happen if you travel. Anyone with two feet can travel, there is no innovation necessary for that.

For the later assimilations, plenty of ideas were offered in the article.

Perhaps the question is, why were there clusters of migration? IIRC, offered explanations have been climate and population size barriers for long periods.

@ dave chamberlin

This line of reasoning pisses some people off because Africans south of the Sahara don’t have any Neanderthal genes. It isn’t sly racism, we would have replaced the Africans if we were superior to them, but we didn’t so we are not.

You could take that further. They are genetically more diverse, so evolutionary more robust.

Unless you can make a case that the bottlenecks of out-of-Africa selected useful genes. Maybe it is the old “potato, potatoe”.