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From:
Subject: Re: [DNA] Celtic haplogroups [haplogroup origin]
Date: Thu, 6 Nov 2003 20:56:08 EST


In a message dated 11/06/03 12:10:43 PM Pacific Standard Time,
writes:

> I think the basic question here is when/how a specific Haplogroup appears?
>
> Do they occasionally "mutate" as a DNA Y-marker does? Are all identifiable
> Haplogroups descended from a specific small tribal group and/or an
> individual?
> If not, do we have more than one R1b, etc.? If yes, then assuming the
> group/tribe stays together, including its various sub-branches, then
> regardless of
> learned "culture" they are all R1b (call it "Celt" or whatever pleases).

Haplogroups are defined by "Unique Event Polymorphisms" (UEPs), mutations
which have occurred only once in all of human history (or at least, they're
treated that way, and minor exceptions are easily recognized). R1b is defined by a
mutation labeled P25. If you order a haplogroup test from FTDNA, you will be
called P25+ if you have that mutation or P25- if you don't.

Everyone living today who is P25+ will be descended from one man, who lived
in a specific place and was born on a specific date. We can guess at the place
by noticing where the concentration is the highest and where there is the most
variety of mutations which occur more frequently, the Y-STRs (the DYS markers
on your FTDNA results that form your haplotype). The diversity of haplotypes
also helps date the origin -- the more time that has elapsed, the greater the
number of distinct haplotypes.

If we can identify SNPs which are found in some but not all R1b, then we know
they occurred after R1b. A few of these have been discovered, so we subdivide
R1b into R1b1, R1b2, etc. Actually, that notation will be changing soon --
Dennis Garvey posted a message a while back about that, as I recall.

I'm reading Kittler's paper right now (and I have an interesting case study
on haplotype/haplogroup results to report when I have time). The R1b mutation
is estimated to be 23,000 years old and was very widely distributed throughout
Europe, making the point of origin difficult to determine.

Newbies who are focusing on the genealogical time frame can safely ignore any
discussion of haplogroups :) Haplogroups are most interesting for "deep
ancestry" from thousands of years ago.

Ann Turner - GENEALOGY-DNA List Administrator
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