GEN • GEN: Michael Cooley's Genetic Genealogy Blog
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5 May 2016
Update for Cooley DNA Group CF04
I've dubbed CF04 the Pennsylvania Cooleys
because several lineages were in the colony and state during the eighteenth
century. But we do know about two roughly contemporaneous John Cooleys, one
of Yorkshire and the other of Oldswinford, both born in England. Obviously,
judging from the STRs, the groups share common roots. See CF04 at the
Cooley DNA Project:
Y-STRs (those numbered boxes) are good for making generalized
groups such as your, but they lack the granularity of Y-SNPs, of
which I've written quite a bit lately. STRs are unstable in that those
numbers (repeats of a specific series of bases) can go both up and down.
For example, I have 34 repeats at DYS449
whereas everyone else in CF01, including my
father, has 33 repeats. (Obviously, I was born with the extra repeat.) If I
had had a son it's possible that he might have been born with only 32.
That's just the way STRs work. But SNPs are different. Once a mutation
occurs (A, T, C or G flipping to another value), it stays from one
generation to the next.
So SNPs are the real thing. Y-STRs can predict the possibility of
the presence of a terminal SNP but we won't know for sure until
they're tested for. The value with Big Y testing is not only that the test
will locate SNPs but that it will find previously unknown SNPs. Of course,
the Big Y is expensive and not everyone can afford it, but if the two
British John descendants, for example, were to test we'd get an idea as to
the degree of their relationship.
In the meantime, SNPs can be tested for both individually and with fairly
inexpensive SNP Packs of a hundred or more. The descendant of the Yorkshire
John (#267628) has added his results to the R1a project. They've put
them in a small group with the prediction of this as his SNP tree:
The R1a admins are really smart about making predictions based on STRs. I
would like to see the rest of you similarly place your results so that we
can see what the admins would recommend. You can do that by going to the R1a
Project and clicking on the JOIN button in the graphic at the top,
right. There is no fee. It's simply an opportunity to make better use of
So, is is true that John Cooley of Yorkshire had the YP4944 SNP, above? FTDNA doesn't yet offer a test
for it. We'd have to go upstream four SNPs to find one, YP1166 (it can be tested for $39 at FTDNA) which is
estimated to be about 1500 years old. At this point, I wouldn't recommend
that test. The Z284 SNP Pack ($99) would also not
find SNPs downstream of YP1166, but it does have an advantage in that if the
R1a admins are wrong, the test would put us on the right course. Still,
there are too many unknowns. The only test at this point I'd recommend is
the Big Y.
And I recommend that everyone adds their results to the R1a Project.