University of Cambridge: You may not have Neanderthal blood after all ... page

[Lewis]

New research raises questions about the theory that modern humans and Neanderthals at some point interbred, known as hybridisation. The findings of a study by researchers at the University of Cambridge suggests that common ancestry, not hybridisation, better explains the average 1-4 per cent DNA that those of European and Asian descent (Eurasians) share with Neanderthals. It was published today, 13 August, in the journal PNAS.

Research raises doubts about whether modern humans and Neanderthals interbred

[Alex Good]

So a common ancestor shared by the humans and neanderthals which none of the humans in Africa had? Either European and African humans evolved separately (which, as I recall, was disproven) or there was interbreeding. If there's another possibility then I don't see it.

[Lewis]

Well ... seems plausible enough.

As they say in the linked article what you find in the DNA "could be explained by hybridisation". And if previous studies did say "could" you can be sure that the newspapers when reporting said "is".

However, their assessment, based on what they think the DNA would look like, is that it isn't likely to be:

the patterns currently seen in the Neanderthal genome are not exceptional, and are in line with our expectations of what we would see without hybridisation.

I guess here you get into is some quite technical material involving a detailed look at the structure, and a set of comparisons, and some judgments based on statistics and estimates of likelihood, which may not even be easily readable, to any non-specialist.

And if there's very much less of the DNA in question in modern African populations than the average per cent or so that turns up in non-African populations, why should we be surprised? These populations represent enormous expansions from small original numbers of individuals and there never would have been mathematically perfect mixing of populations within the continent of Africa, owing to space, geographical constraints, and so on.

Maybe the problem here is the same as one gets in the nutritional field: that someone gives an interpretation of some data, and it immediately gets reported as a "finding". People then wonder what the heck's going on when a different interpretation is advanced.

[Alex Good]

Well their results basically support the multiregional human evolution theory. And if they're right then this brings back up the possibility that humans evolved from in multiple locations at the same time.

Really it's either interbreeding or a complete overhaul of the accepted litterature.

[Lewis]

I don't see that it means very much for modern humans. Either way round it's a small amount of DNA. Some of us have it; some of us haven't; and no-one has very much. And does it signify whether it came in, say, 40,000 years ago, or, say a few hundred thousand?

Neither has anyone even suggested that it explains anything about modern humans that we were already aware of but didn't know the reason for -- say, that some people were susceptible to a particular disease and some weren't.

But potentially, I suppose, it offers an answer to the question "whither did the Neanderthals go?".

Now, apparently, someone else is claiming to have put a date on the DNA, and their date makes it of Neanderthal origin.

I only saw a brief news story on this. What I suppose is this.

Suppose I sell a dozen coats. One is put away in a wardrobe. The others continue in use. Over time some might lose buttons, which are then replaced with other buttons that may be slightly different; maybe someone adds a pocket; maybe someone sews a badge on one. We would still say that these are "the same" coats but they would be very slightly different -- by a button or so. If someone came up with an estimate of how fast the coats get altered, then he could also produce an estimate of the time at which I sold them.

Thus for some DNA. It changes over time. Hence the use of the Y-chromosome for trying to map the movement of populations in historical time. Because it mutates neither too fast nor too slow it becomes useful for that purpose.

[Alex Good]

Somehow I think this was all just an attempt to avoid racial altercations. Since, you know, this kind of proves that 100% blacks are different than everybody else.