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Archiver > GENEALOGY-DNA > 2006-07 > 1152364275


From: "Ken Nordtvedt" <>
Subject: Re: [DNA] R1b SNP page updated
Date: Sat, 8 Jul 2006 07:11:15 -0600
References: <003801c6a286$4f58b9d0$4001a8c0@BigMem2>


From: "John McEwan" <>

> I personally think the Irish cluster is far older than its TMRCA
> suggests which is about 3400 years. I think it is a remnant of an
> earlier R1b group and I also feel that it was unlikely to have even been
> in Iberia in the last glacial period, because it would have left some
> more substantial trace behind. This is getting pretty radical compared
> with the existing scientific dogma, but I put it out there for comment.


We probably use a different set of markers to make the age estimate, and if
you use a TMRCA we use different methods (I use a variance or ASD measure),
but I get using 26 markers an ASD for northwest Irish R1b which is 59.8
percent that of AngloSaxon I1a (my base standard). If I use 10,000 years as
I1a-AS age, which is somewhat arbitrary but in the ballpark of Rootsi ages,
then northwest Irish R1b is substantially older than your estimate but still
young enough to have had its founding in situ (British Isles). It's almost
complete absence on the continent makes me very suspect of any founding back
there --- north or south (with France being the usual hole in our
understanding)

My ASD for northwest Irish R1b is by the way quite close to that found for
the Scot variety of Isles I1b2a1 (M284+) = old I1c-Isles. It would be
interesting to know the climate history of the most northerly parts of the
British Isles in order to get a sense of when that country opened up for
habitation if it were substantially later than the more southerly parts of
the British Isles?

Ken


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