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From: "brian quinn" <>
Subject: Re: [DNA] Could our big brains come from Neanderthals?
Date: Thu, 9 Nov 2006 16:25:44 +1100
In-Reply-To: <mailman.4949.1163033971.22941.genealogy-dna@rootsweb.com>


Ian, well they didn't test any Australian aborigine who maybe first settle
Australia 50-60,000 years ago. They were similar to Papuans in Mtdna at any
rate. The ydna in present pop is from some Dravidians who sailed in later
(perhaps bringing the microcephalin gene).


The hobbits on Flores must have missed out?

info and further refs:

http://www.the-scientist.com/news/20050909/01/

Brian quinn


Message: 3
Date: Wed, 8 Nov 2006 21:00:56 -0000
From: "Ian & Mary Logan" <>
Subject: Re: [DNA] Could our big brains come from Neanderthals?
To: <>
Message-ID: <000d01c70378$febfa5c0$>
Content-Type: text/plain;charset="iso-8859-1"

...........Ann wrote

Free full-text is available online -- I just now printed out the article.

http://www.pnas.org/cgi/reprint/0606966103v1

I suspect this story will get wide coverage in the news, so it might pay to
check http://news.google.com (maybe keyword microcephalin) for additional
press
coverage with different slants. Also check out John Hawks' blog -- he just
returned from a conference about Neandertals, and he adds some commentary
gives
more context.
..............

This posting from Ann Turner links to the new paper:
..
Evidence that the adaptive allele of the brain size gene microcephalin
introgressed
into homo sapiens from an archaic homo lineage
P Evans, N Meekl-Bobrov, E Vallender, R Hudson, B Lahn
..
and I have not been able to resist replying to the list.


So let me say this paper is one of those that 'batters' the reader with
Science
and then makes comments that are liable to be mis-reported.

If I may make a few hopefully simple comments:

The researchers are looking at the gene Microcephalin and have determined
there
are two alleles 'D' and 'non-D'; and suggest 'non-D' on a chromosome is the
ancestral form, whereas 'D' is the more recent form.

So far, so good.

The researchers then propose that the ancestral form is perhaps 1,100,000
years
old, whereas the recent form is perhaps only 37,000 years old; and then try
to explain
what might have happened to account for this.

They use the term 'introgression' to indicate that the recent form possibly
disappeared
from the main line of Homo Sapiens and then was 're-introduced' into the
main line
by some small population that had been separated for the intervening
1,063,000 years.

This is really quite a logical deduction and it would suggest that a small
group of early
people were indeed separate from the main line of Homo Sapiens for a very
long period.
And, I do not see anything wrong with this contention, unlikely though it
might seem.
I really do not mind several hundreds of thousands of years, although a
million
does seem rather a long time.

However, I do feel it is mis-reporting to take this deduction further and
mention
the Neanderthals.

In the paper the most appropriate line in the article describing this reads:
'Speculation about the identity of the archaic Homo population
from which the microcephaplin D allele introgressed into the
modern human gene pool points to a Neanderthal lineage as
a potential (although by no means only ) candidate.'

In my opinion there is nothing to suggest that the Neanderthals formed the
separated
line with 'D' - and what is wrong with just isolated Homo Sapiens !

So overall, I feel the paper and the reporting just go too far.

Any comments ? Does anyone see more in this paper than I have seen ?

Ian






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