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Archiver > DNA-R1B1C7 > 2009-04 > 1240157775


From: David Ewing <>
Subject: Re: [R-M222] Byrne TMRCA Estimates
Date: Sun, 19 Apr 2009 10:16:15 -0600


Boy, am I torn. I have been reading this thread with interest and aching to
put in my two cents, but I have not spent enough time crunching general
R:M222 data to be confident of making a worthwhile contribution.

That said, I think we are barking up the wrong tree by comparing histograms
of raw genetic distance for various putative places of origin. Consider that
we could have two very tight clusters within R:M222 such that the haplotypes
within each cluster were all identical, but each of the clusters differed
from the R:M222 modal at four different markers. Both clusters would be
genetic distance 4 from the R:M222 modal, but the two clustes would be at
genetic distance 8 from one another. Genetic distance histograms would sort
these clusters into the same pile, but clearly the cluster lines would have
diverged long enough ago for four independent mutations to have taken place
in each.

I think Sandy is on the right track by looking for matches off-modal
markers, though I do not understand why she wanted to look for off-modal
matches specifically with Ewing. (Of course this is interesting to the Ewing
project, and it was very interesting to me to see the similarity of Cowan
and Ewing, given the onomastic connection.) My thought would be to start
with the R:M222 modal and see if we could find any pattern of off-modal
matches considering all of the surnames for which we have enough haplotypes
to compute a meaningful surname modal.

Maybe I should have at least a dilettante's look at the data, but I know I
will not have the patience to go through all the R:M222 haplotypes and
compute surname modals for myself. Can someone refer me to a list of R:M222
surname modals?

David Ewing

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