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Archiver > GENEALOGY-DNA > 2003-11 > 1068214290


From:
Subject: Re: [DNA] Celtic haplogroups [haplogroup origin]
Date: Fri, 7 Nov 2003 09:11:30 EST


In a message dated 11/06/03 10:15:05 PM Pacific Standard Time,
writes:

> How about these subdivisions of the
> various haplogroups (e.g., R1b1, R1b2), is it clear that these EUPs occurred
> AFTER the primary UEPs that define the haplogroup? If so, did the mutations
> that define these "sub-haplogroups" (is there a new term for this?) occur
> more in the 1-5 thousand year range, a time period when history and culture
> really began?

Yes, the UEPs for subgroups occur after the primary one. Take a look at the
YCC chart for R1b. All the sub-haplogroups R1b1, R1b2, etc. share the P25
mutation, but each sub-haplogroup has an additional mutation which is not found in
the other subgroups. That demonstrates that P25 is older. The levels on the
YCC chart can tell you the order in which mutations occurred, but not exactly
when.

I can't think of a great analogy right now, but consider geography instead of
time scales. Everyone who lives in Philadelphia or Pittsburgh also lives in
Pennsylvania, but not everyone who lives in Pennsylvania lives in Philadelphia
or Pittsburgh. The R1b level would be like the state, and the R1b1 or R1b2
levels would be like the cities. There would also be many Pennsylvanians who
don't fall into either category. On the YCC chart, they would be labelled R1b*
(the star is a wild card, which stands for all R1b not otherwise classified).
When we "discover" more cities in Pennsylvania, we can add more categories to
R1b: R1b3 and R1b4 etc. When we "discover" neighborhoods in Philadelphia, we can
add another level to R1b1, which would get the label R1b1a. The letters and
numbers alternate, rather like the way you used to do outlining in school.

SNP discovery is more difficult the closer you get to the present. The SNPs
will be rarer and rarer (they've had less time to accumulate descendants), so
you have to sample more and more people to find them. But in principle, yes,
there will be SNPs in the 1-5 thousand year range.

Ann Turner - GENEALOGY-DNA List Administrator
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