Archiver > GENEALOGY-DNA > 2005-06 > 1119913759

From: (John Chandler)
Subject: Re: [DNA] P25
Date: Mon, 27 Jun 2005 19:09:19 -0400 (EDT)
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Bill wrote:
> Lord knows, STRS are revolutionary tools, but beyond a 1000 years ago
> we come to a screeching halt with our SNPS offer the only
> door back to the past.

You keep making statements like this, but they've never been true.
The thing that comes to a halt is *documentation* -- and usually much
more recently than a thousand years ago. Without documentation, DNA
testing is just population genetics. For the record, though, STR
testing offers resolution 10,000 years into the past. 10,000 years is
also significant in another way. Using present technology, that is
about how long it will take to find enough SNPs to make "deep" SNP
testing a reality. As I've pointed out before, the depth you're
looking for will require about a *million* new SNPs. Here's what we
would need to accomplish this goal: sequence the entire Y chromosomes
of several million men all over the world. It would help to have
genealogical data for all of them, but we could do without if
necessary. It would be a matter of building a phylogenetic tree down
to 1000 AD for the male half of the entire species. It's doable, but
only with sufficient data.

John Chandler

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