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Archiver > GENEALOGY-DNA > 2004-06 > 1087049307


From:
Subject: Re: [DNA] haplogroups defintions [SNP testing]
Date: Sat, 12 Jun 2004 10:08:27 EDT


In a message dated 06/11/04 3:25:27 AM Pacific Daylight Time,
writes:

> As the
> group admin I may go ahead and do the SNP test so we have at least
> one person in our group who has had it. I would presume that all
> others who match me in the STR tests would then also be able to
> say with 100% confidence that they are from the same haplogroup.
> Correct me if I'm wrong as this is all new to me.

For all practical purposes, your SNP test would apply to anyone within in
your project who matches you. There is a theoretical possibility that the same
STR haplotype can show up in different haplogroups. There are reports of this
happening in the literature, about 1% of the time, but that was back in the days
when they typically used just 6 markers. By the time you reach 12+ markers,
the frequency would drop markedly.

But.. when the day comes that SNP tests are available for finer divisions of
haplgroups, we may encounter the same STR haplotypes in say I1b1 and I1b2.

> Is this why they estimate that a person is in haplogroup I but if the SNP
> test is run they can pinpoint it down to haplogroup I1b1a for example?

The current SNP tests won't pinpoint it that closely. Your order page will
tell you exactly what they are testing for.

> For the SNP tests do you get the results back for the markers that
> were tested or only a specific haplogroup name?

They'll tell you which SNP marker came back positive.

Ann Turner - GENEALOGY-DNA List Administrator
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