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Archiver > GENEALOGY-DNA > 2005-05 > 1117215002


From: (John Chandler)
Subject: Re: [DNA] Middle Eastern ancestral markers on new Euro 1.0 test
Date: Fri, 27 May 2005 13:30:02 -0400 (EDT)
References: <20050527161222.77678.qmail@web52104.mail.yahoo.com>
In-Reply-To: <20050527161222.77678.qmail@web52104.mail.yahoo.com> (messagefrom ellen Levy on Fri, 27 May 2005 09:12:21 -0700 (PDT))


Ellen wrote:
> The "Middle Eastern" markers (whatever those are
> defined as) were probably spread through Europe, as
> you postulate, by the Romans. However, I think you
> can reach much further back in time as well.

That pretty much sums it all up.

For specifics, the "Middle Eastern" markers are those which are more
frequent in a (small) collection of people that AncestryByDNA
considers to be typically Middle Eastern, compared to three other
(small) collections of people considered to be typically Northern
European, Southeastern European, and South Asian. It must be
emphasized that the choice of these reference samples is an art and
not a science. At any rate, the people in question are certainly
drawn from populations that NOW live in the four respective areas.
Any ancient admixture of East Asians or Africans in some of the target
populations will clearly affect the measured allele frequencies and
shift all the test results accordingly. (But an admixture so ancient
that it's uniformly spread through all of the populations will
obviously cancel out.)

The ethnicities being "measured" here are not absolute in any sense.
They are all relative to the reference samples. It would probably
help everybody to think more clearly about this test if we used
cryptic abbreviations instead of the formal long names I scrupulously
spelled out above. The A-by-D web site does a very good job of this
by using four different sets of terms for the four categories. I
propose that we go one step further and adopt one-letter abbreviations:
N, G, M, and S. (Clearly, "SA" is too much like "SSA" from the global
tests.) If we recognize this system as the mathematical abstraction
that it really is, then there is no need to agonize over how Charles
came to be 20% G and 25% M.

John Chandler

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