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Archiver > GENEALOGY-DNA > 2011-01 > 1294227252


From: "Debbie Kennett" <>
Subject: Re: [DNA] Recommendations for DNA testing
Date: Wed, 5 Jan 2011 11:34:12 -0000
References: <5F3B12A4D09E4D70AF3C541871E0610D@NEWGAMES><001e01cbaabb$56d99f20$048cdd60$@dgmweb.net><DD790F8C0FD347BEBAF1382ABD84740F@JohnPC><AANLkTikbhyxiO6dMmsRqDJa06Ndu5=iS9PwWkxg6+C6k@mail.gmail.com><96275237-1E93-4727-9884-3A39F35DFE88@vizachero.com><AANLkTikLydTUhjLtwdo=+mh0N-7kaSosMQy2BPe3N3T2@mail.gmail.com><BA5BD49888314B158D17B42DF716178F@NEWGAMES><AANLkTinfHkoQS=5RfCOXed_fk8PypKQ1eAs22gYH8Uwp@mail.gmail.com><7638B067C67844DABB0485BCEB7C84C7@NEWGAMES><AANLkTinHP1QZGayyo3ym+SqA+tAF448hfFwBNjCqs-0o@mail.gmail.com>
In-Reply-To: <AANLkTinHP1QZGayyo3ym+SqA+tAF448hfFwBNjCqs-0o@mail.gmail.com>


Bob

23andMe sometimes get the mtDNA haplogroups wrong too - or at least the
subclades. They have me down as a U4a2b. I know from my full sequence mtDNA
test at FTDNA that I am a U4c1 (or U4c1a1b according to our U4 project).
23andMe only test about 2000 mtDNA SNPs compared to 16,569 bases in the full
sequence. Also, you can't use your 23andMe mtDNA results to compare your
results with people from other testing companies.

As part of my one-name study I am also looking at surname origins for which
SNP testing is very useful. I always try and get one person from each
genetic grouping to get SNP-tested. SNP testing also provides an extra level
of confirmation of relatedness. I have for example two lines - Cruwys and
Cruise - which I believe diverged shortly after the Anglo-Norman invasion
Ireland of 1169 with one line staying behind in Devon and the other going to
Ireland. They match on 57 or 58 out of 67 markers. One person from each line
has now taken a deep clade test and they are both confirmed to be in the
same subclade (R1b-L48) so we have greater confidence that the lines
probably are connected. With R1b people can have very similar haplotypes and
yet sometimes be in completely different subclades.

As more Y-DNA SNPs are discovered there is a real possibility in some
instances that they will have a direct genealogical application as branch
identifiers.

23andMe is interesting for health testing and the comparison of 23andMe
Y-SNPs has brought some useful new discoveries, but for anyone interested in
their Y-DNA deep ancestry they really need to be able to order SNPs as and
when required.

I'm not sure what you mean by "However, I do recommend Y-SNP testing to
those who are trying to use relatedness (TMRCA) techniques, although I try
to discourage them from going down that path." Are you saying that you are
actively discouraging people from getting SNP tested?

Debbie Kennett



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