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Archiver > GENEALOGY-DNA > 2008-04 > 1208811437


From: "Ken Nordtvedt" <>
Subject: Re: [DNA] New Issue of Journal of Genetic Genealogy
Date: Mon, 21 Apr 2008 14:57:17 -0600
References: <BAY111-DAV5DF08218AAD19B174D995B1E10@phx.gbl>


----- Original Message -----
From: "Lawrence Mayka" <>

It brings into question the claim that
> DYS455 deletion is "almost unique",

Please suggest what "almost unique" then means to you. I find the use of
"deletion" a bit puffy. I guess that makes it easier to draft it
as a surrogate SNP ---- its a deletion rather than result of possibly
multiple down mutations. It took me a couple weeks to realize that
the introduction of the term "deletion" did not mean some new kind of
mutation.

The presently seen F and H are modal 10 at DYS455 (as I1b2* is as well).
Since most clades of F, and so far IJ as well as I*, are probably extinct,
we have no way to know if the 455 = 8 of the I1a (soon I1) MRCA resulted
from a couple one-step down mutations or by a "deletion", with the latter
apparently meaning by its users a possible down mutation of multiple repeat
units. We have 600 generations from the I1a MRCA back to the point where
its branch line of ancestors split from the rest of "I" . Then we have the
unknown time of existence of I*; then the unknown time of existence of IJ.
We have no evidence for what the haplotypes on that total branch line
which could very well have extended over 1000 generations looked like,
although the probability that DYS455, given its apparent mutation rate,
would have mutated twice is pretty low. From the prevalence of 455 = 11 in
J as well as I other than I1, parsimony would suggest that F's 10 at 455
first suffered a one-step "insertion" up to 11 by IJ, however, leaving
"just" the last 600 generations of the I1 ancestral branch line for DYS455
to get down to 8 repeats one way or the other.

Ken


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