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Archiver > HARRIS-DNA > 2005-05 > 1116814057
From:
Subject: Re: [HARRIS-DNA] mismatch interpretations: follow-up
Date: Sun, 22 May 2005 22:07:37 EDT
Hi Gregg,
Thanks for clarifying the matching system, as many of us are looking back 12
to 16 generations, so that a 23/25 match or higher is quite acceptable to
find a family group and MRCA, and even much further back finding more mutations
and perhaps a lower percentage probability of a family group and most recent
common ancestor.
As I have said, Harris research is the most difficult of all, so that we
need every advantage and clue that we can find and since DNA seems to be able to
help us find family groupings, it is of immense value to guide us along the
right path to our ancestry, and that is why I want you to understand that the
close matches are doing just that, and that the 12/12 matches to the 19th or
20th century are just not that helpful for some of us, but likely are of much
help to others.
Sincerely,
James E. Hargraves
In a message dated 5/22/2005 3:38:58 PM Pacific Standard Time,
writes:
I don't mean to give that impression. Obviously, it depends on the number of
generations that are hypothesized to be between the two participants. If
they are supposed to be brothers, and they are only 23/25, then I would say
that is very unlikely. But 23/25 for proposed 9th cousins....I don't have
much problem with that.
Also note that because the mutation rate is non-zero, as the lines diverge,
you begin to expect a mutation OVER a complete lack of mutations in both
lines. So obviously I don't think that only perfect matches should be taken
to indicate a single family origin. It is just that in the case of 12
markers, you have to have a lot of generations between. Even in 25 markers
you need something like 6th cousins for a single mutation to edge zero
mutations as the most probable.
Gregg Bonner
Mismatches say something to every DNA analyst that I have ever read about or
consulted with and they certainly say something to the FTDNA system of
analysis which allows 11/12, 23/25 and 33/37 mismatches as matches for
genealogical purposes. Some FTDNA sites are allowing 22/25 as matches in
certain haplogroups. If you are going to make statements like that, I would
hope that you would qualify them as to the degree of mismatch, because you
are giving the impression that only perfect matches count and that simply
isn't true, by all DNA standards being used today for genealogical research.
Sincerely,
James E. Hargraves
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