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Archiver > GENEALOGY-DNA > 2005-11 > 1133203669


From: charles <>
Subject: Re: [DNA] YSNP testing, hobby scientist forces, convergence, andback mutation issues -- to YSNP or not to YSNP
Date: Mon, 28 Nov 2005 13:47:49 -0500
References: <438B272B.9040309@comcast.net> <003901c5f436$7bbbe550$71509045@Ken1>
In-Reply-To: <003901c5f436$7bbbe550$71509045@Ken1>


All:

I think it is agreed that hobby genealogists and hobby genetic
anthropology scientists are driving forces in the population genetics
and genetic anthropological fields at the moment.

Regarding YSNP testing and genealogical uses, and the much discussed
principle of convergence used often in the context of trying to explain
why people with different surnames have the same haplotype (when other
simpler things explain it) ... right now the YSNP test is not very
useful for such traditional genealogical purposes compared to the 37 and
43 marker haplotype tests available. Encouraging lots more people tested
at 12 markers to be YSNP tested will certainly aide the field of Genetic
Anthropology, but will add little traditional genealogy useful
information to genealogists running surname projects compared to
upgrading from 12 markers to a 37/43 marker haplotype.

However if the YSNP testing labs can keep adding finer and finer
division YSNPs it could become much more useful over time. As we add
more and more finer sub-divisions of the YSNP tree we are moving closer
and closer to groups of people who are more recently related in time.
But at present we are still in time frames of thousands of years ago
with YSNP testing haplogroups and sub-clade resolutions.

If the labs can eventually increase the number of sub-group SNP
enormously and the alphanumeric YSNP grew to 12 or even 37 characters,
R1b1c6a7b2d....., we would have a very powerful tool to add to the 37/43
marker haplotype tool. But we're a long way away from that day with
YSNPs, imo.

Regarding the issue of convergence we also need to realize that as we
further and further sub-divide the YCC type tree the haplotypes will
look more and more alike ... so we should not confuse that enate
principle with the concept of convergence where haplotypes are
independently mutating over time towards each other in state. Many have
talked about convergence in principle. But I have yet to see one example
occur for two 37 marker Y-DNA matching or nearly matching haplotypes be
proven to be in two different major haplogroups, i.e., for the
haplotypes to match exactly or very closely and it be proven via
independent testing by two or more labs. I suspect any "data mining"
examples dug up as "proof" are due to lab errors, clerical errors, or
polluted databases. With smaller haplotype sizes say 6 markers or less,
convergence is more likely to be observed. Convergence for one or two
YSTR markers can probably be easily shown. That is simply due to the
statistics involved of which others are better qualified than I to
discuss and explain. But for a 37/43 marker haplotype, I believe
convergence if ever demonstrated will be exceedingly rare. And at that
point we need to ask ... are we really dealing with the principle of
convergence .... or is it more likely to be a back mutation event for
the Y-SNP marker from derived back to ancestral, etc., that explains it.

We need to be cautious with interjecting the scientifically possible,
but unproven at 37 marker haplotypes, principle of convergence when
discussed within the context of comparing genetically close 37/43 marker
haplotypes for people who happen to have different surnames, imo. There
are far more simpler and probable explanations. For some examples see
the Risks and Rewards section of my intro report:
http://www.kerchner.com/anonftp/pub/introg&g.htm

And we need to clearly explain to genealogists and the masses being
offered YSNP tests, the limits of what additional genealogically
relevant information is obtained by YSNP testing ... and also with
surname project participants, before recommending large scale YSNP
testing within a surname project. Typically only one person in each
related cluster in the surname project needs to be tested. That is what
I recommend in my projects.

But of course there is always the altruistic reason to increase the data
available to the population geneticists and genetic anthropologists as
the National Geographic Society Genographic Project is doing. As long as
the person being YSNP tested knows the difference between "deep
ancestry/anthrogenealogy" relevant information and "traditional
genealogy" relevant information and who is benefiting the most at
present from each type of test, the genealogy side of the project or the
deep ancestry project pursuits interests, all will be fine in the short
term and the long run. JMHO.

Charles Kerchner, P.E.
http://www.kerchner.com/kerchdna.htm


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