GENEALOGY-DNA-L ArchivesArchiver > GENEALOGY-DNA > 2010-02 > 1267116744
From: "Lawrence Mayka" <>
Subject: Re: [DNA] Multiple Mutations of SNPs
Date: Thu, 25 Feb 2010 10:52:24 -0600
In other words, a "flippy" SNP (Thomas Krahn's term) is no better than a
We need to keep this in mind particularly in the older and more prolific
haplogroups. In one forum, someone was proposing the use of a "flippy" SNP
at a level directly under J2a. I had to point out that J2a was apparently
at the very center of the Neolithic Revolution. J2a is so old and so
continuously prolific that any "flippy" mutation will almost certainly have
occurred more than once in its lifetime, and hence cannot be used for
categorization independent of additional context--either STRs or downstream
SNPs. In other words, it can be treated as a slow STR, but not as a
traditional tree-node SNP.
But perhaps you are going further and pointing out that _every_ SNP will
eventually fall into this category, if every Y chromosome in the world gets
thoroughly tested. That is, somewhere in the world is an L21+ man (within
R-P312) in whose patrilineage the L21 SNP occurred independently of the
historic mutation we are all familiar with. I feel sorry for him already,
because his test results are likely to be misinterpreted even by experts.
> From: [mailto:genealogy-dna-
> ] On Behalf Of Ken Nordtvedt
> Nothing radical changes when we find multiple occurrences of snps. We
> examine the full context of haplotype STRs and other snps it carries.