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Archiver > GENEALOGY-DNA > 2010-03 > 1269532870


From: Jonathan Day <>
Subject: Re: [DNA] Life, Jim,but not as we know it (was Fossil finger points to new h...
Date: Thu, 25 Mar 2010 09:01:10 -0700 (PDT)
In-Reply-To: <F823FA2732FF48579E67E35ECD63B337@IanPC>


They say something about the method of their deduction - assuming linear rate of change, for example - from which we can infer something about the data. It may well be that their assumptions are correct, and I can think of no place better equipt to validate at least the mtDNA rate of change assumption than this list, as Ian keeps handling the submissions of full mtDNA sequences. They're not idiots, so I'm guessing the assumption is either dead-on or close enough, but checking won't hurt.

If, after allowing for the noise that all experimental data is subject to, the rate of change of mtDNA is not approximately linear, or is approximately linear but the gradient differs enough from the one used in this research, then the time of divergence is incorrect. Otherwise, that part of the claim is correct. We should have sufficient data to test this.

IIRC, what we do NOT have is any mtDNA from modern humans not on mtEve's lineage. If I am correct on that, this means we don't know what the diversity was during the timeframe in which non-mtEve modern humans lived. Nor do we know what that timeframe was, beyond the fact that mtEve was (almost) certainly not the only female modern human alive at the time.

Also IIRC, they checked against a representative example of Neandertal mtDNA, but Neandertal mtDNA will have presumably have formed haplogroups the same as ours, only we have far fewer examples and therefore much less idea of just how many groups there were.

If we assume zero cross-hominin relationships AND that our fossil evidence of modern human emergence is good enough to get an accurate date, then I guess you could numerically derive the maximum theoretical spread and call anything in that spread a "modern human". This would include all extinct lines for which no data exists, along with lines that could have emerged in theory but never did. Not sure how useful such an analysis would be, though.

What we also don't have are the actual mtDNA values, any yDNA values that might help confirm their claim, the condition the mtDNA was in, etc. I hope they publish more, eventually.

--- On Thu, 3/25/10, Ian Logan <> wrote:

> From: Ian Logan <>
> Subject: Re: [DNA] Life, Jim, but not as we know it (was Fossil finger points to new h...
> To:
> Date: Thursday, March 25, 2010, 7:06 AM
> Ann & List
>
> The new paper mainly deals with the methodology by which
> they obtained the new mtDNA sequence.
> Unfortunately, they say very little about the actual
> results
> - only sweeping conclusions.
>
> Presumably the actual sequence will appear in time - but
> when ?
> But from what is said, the hominid strain appears to be
> unlike
> the neandertals, and even further from modern humans.
>
> But until the sequence becomes available it is not be
> possible
> to say just how novel this new hominid strain might be.
>
> Ian
>
>
> -----------------------
> Ann wrote:
>
> John Hawks has some commentary in his blog:
>
> http://johnhawks.net/weblog/reviews/neandertals/neandertal_dna/denisova-krause-2010.html
>
>
> Ann Turner
>
>
> writes:
> > If it's a new species, then the above doesn't have any
> meaning.
>
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