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From:
Subject: Re: [DNA] DNA Analysis for Conventional Genealogy vs. Deep Ancestry
Date: Wed, 8 Jun 2005 16:05:19 EDT


In a message dated 6/8/05 11:16:20 AM Pacific Daylight Time,
writes:

> Are there techniques that we could be developing that would better allow
> determining exact connections? I suspect that if we tested enough markers
> (perhaps including types that are not now tested) we would find that for
> each transmission event there is some sort of change/mutation. Although some
>
> of these might not have long-term stability, we might be able to find
> something unique for each transmission event, allowing us to pinpoint the
> exact connection with a lineage. Maybe some enterprising person could even
> find a way to screen the genome for changes connected with a specific
> transmission event or lineage.

I'm a bit pessimistic about this approach for the near-term future, but I
think we can revisit it when the cost of DNA sequencing goes down. It's
theoretically possible that SNPs could be used in the way you envision, since a SNP
could very well occur nearly every generation SOMEwhere in the 25-some million
bases on the Y-chromosome that are amenable to sequencing. If you'll search the
archives for the phrase "SNP discovery" you'll find some thoughts on the
matter, which you may have overlooked because they were buried inside messages
about deep ancestry :)

SNPs are slow but permanent records of cumulative changes that have occurred.
In another message Bob McLaren brought up the possibility of very fast-moving
markers to define branches in a familiy tree. That would be a two-edged sword
-- you would certainly see some differences, but would they persist long to
define a branch? There is a fast-moving marker called MSY1, but I gather it's
very complex to measure, and there's not much in the literature about it.




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