Aspergers and Neanderthals
Oct. 29th, 2007 12:26 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
jamesqThe site with the Aspy Quiz have an interesting hypothesis that Asperger's Syndrome may be an expression of Neanderthal genes in modern humans - that what we perceive as deficits is actually stuff adapted to a different species (i.e. they don't lack the ability to get non-verbal cues, they're just wired to get a different set of non-verbal cues).
I'm not really qualified to judge this theory. On the one hand it does sound plausible. On the other-hand it has a lot of conjecture of the humans-have-brown-hair-so-they-can-hide-in-coconut-trees-better type.
On the gripping hand, I can think of a lot of alternate hypotheses for some of the behaviors described. For example, they posit that Neanderthals had a more Bonobo-like sexual appetite and that is why there is a higher prevalence of odd sexual mores amongst the Europeans (and their descendants in North America and Australia). How they would know Neanderthals were like that to begin with I don't know. Also, Western liberal culture allows that and is a very recent phenomenon. I wouldn't expect that (liberal sexuality) in cultures that are more hidebound and traditional. You could test it by looking at populations that are not descended from Europeans, but are still western in their outlook, and seeing if they're like a bunch of circus freaks in the bedroom too. Sexually, are American Blacks more or less like their genetic ancestors or their current culture? How about the Japanese?
Finally, the author's assertion that the various "races" of humanity have different IQs is at best controversial and at worst out-and-out racist.
Is it a viable hypothesis? Meh. It needs a lot of work.
As an aside,I'm in the "Neanderthals where assimilated into modern Humanity's gene pool" camp myself, mostly because I think I have an above average number of those genes. (Not so much anymore, thanks to a little more research - Q 2007-10-31 11:10) That picture of the Neanderthal kid on the link above could well be me at eight-years old, except that I had a somewhat more Gaulish (i.e. big) nose. Certainly the kid's attention to hair-combing/cutting is the same as mine was at that age.
I'm not really qualified to judge this theory. On the one hand it does sound plausible. On the other-hand it has a lot of conjecture of the humans-have-brown-hair-so-they-can-hide-in-coconut-trees-better type.
On the gripping hand, I can think of a lot of alternate hypotheses for some of the behaviors described. For example, they posit that Neanderthals had a more Bonobo-like sexual appetite and that is why there is a higher prevalence of odd sexual mores amongst the Europeans (and their descendants in North America and Australia). How they would know Neanderthals were like that to begin with I don't know. Also, Western liberal culture allows that and is a very recent phenomenon. I wouldn't expect that (liberal sexuality) in cultures that are more hidebound and traditional. You could test it by looking at populations that are not descended from Europeans, but are still western in their outlook, and seeing if they're like a bunch of circus freaks in the bedroom too. Sexually, are American Blacks more or less like their genetic ancestors or their current culture? How about the Japanese?
Finally, the author's assertion that the various "races" of humanity have different IQs is at best controversial and at worst out-and-out racist.
Is it a viable hypothesis? Meh. It needs a lot of work.
As an aside,
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no subject
Date: 2007-10-30 12:07 am (UTC)http://news.bbc.co.uk/2/hi/science/nature/7062415.stm
DNA analysis is tending to show that Neanderthals did not contribute to the modern human gene pool.
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Date: 2007-10-30 12:36 am (UTC)By this reasoning, the differences in appearance between modern Europeans and the Neanderthal is simply a case of parallel evolution. Basically, cold-adapted, high latitude people are going to end up looking similar.
OK, I'm willing to buy that. It's still not settled, but this is the research that's going to settle it eventually.
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Date: 2007-10-30 01:10 am (UTC)no subject
Date: 2007-10-30 02:17 am (UTC)no subject
Date: 2007-10-30 03:17 am (UTC)Not surprisingly, the further apart we are on the evolutionary tree the more differences there are in that sequence. This is the basis for the estimates they make on how long ago we diverged from common ancestors, and the essence of the arguments being made for when we diverged from Neanderthals in the first place.
I wish I could see the full article, but I think they are playing fast and loose with the word 'mutation' for the differences they see in Neanderthal MC1R. Really, they should use that only if the sequence is substantially different from what you would expect from a "normal" Neanderthal (I use that word in the sense of normal curve - ie most Neanderthals). And since they've only ever tested TWO Neanderthal MC1R genes and BOTH of them had that 'flavor' of MC1R...
But you are right, the sequence variation that they found in the Neanderthal MC1R is very similar (but not identical) to the variation in modern human redheads. Both of them have a difference that they would predict (based on how the MC1R protein should look and act) to result in reduced MC1R function - at least compared to modern human "normal" MC1R. And since they are different variants, this argues for parallel evolution, or independent events, not a shared ancestor for that change.
I remember being at the American Society of Human Genetics meeting when they reported the very first isolation of Neanderthal DNA probably 10 years ago. Actually it's amazing how slowly the field is moving.
But archaic DNA is extraordinarily hard to work with and the experiments are prone to all kinds of error. There were two recent publications that presented quite different estimates on the timing of the genetic split with us and now someone's thrown down the gauntlet to argue that the group with the more recent estimate (and the one with the most estimated Neanderthal DNA kicking around in us) may have a contaminated specimen (with modern DNA).
In general, the hypothesis that there's very little Neanderthal in us is holding out (after we split I mean- we still share over 99% of DNA with them, just like chimps. But just like chimps, after splitting from our common ancestor we didn't go and breed Neanderthal specific stuff back in).
Which makes things like the Asperger's theory or the Sexual behavior thing seem rather premature at best, whimsical if I'm feeling generous, or downright silly at worst.
Sequencing and analysis of Neanderthal genomic DNA.
Science. 2006 Nov 17;314(5802):1113-8.
http://tinyurl.com/2jzcg6
Analysis of one million base pairs of Neanderthal DNA.
Nature. 2006 Nov 16;444(7117):330-6.
http://tinyurl.com/2qh55z
Inconsistencies in Neanderthal Genomic DNA Sequences.
PLoS Genet. 2007 Oct 12;3(10):e175
http://tinyurl.com/2qh55z
no subject
Date: 2007-10-30 03:47 am (UTC)Which reminds me, do you know
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Date: 2007-10-30 11:47 pm (UTC)no subject
Date: 2007-10-31 10:37 pm (UTC)no subject
Date: 2007-11-01 02:26 pm (UTC)no subject
Date: 2007-11-03 04:54 pm (UTC)