GENEALOGY-DNA-L Archives
Archiver > GENEALOGY-DNA > 2005-11 > 1133268218
From: "Phil Goff" <>
Subject: Re: [DNA] YSNP testing, hobby scientist forces, convergence, and back mutatio...
Date: Tue, 29 Nov 2005 06:43:38 -0600
References: <e4.75ea9059.30bda292@aol.com>
EMartin250,
Please sign your name to posts so we may address you properly. There is no
need to test deceased persons to determine where a mutation happened.
Rather, you just need to work your way up the line of descent. For example,
you could test the first cousin of WXR9N. If this first cousin matches
WXR9N, the mutation happened no more recently than their common grandfather.
If the first cousin matches EGVHQ, who presumably is the same as the "modal"
for the MRCA, then the mutation happened either in WXR9N or his father. You
keep working backwards, testing second cousins, third cousins, until you
find where the mutation happened.
Having said the above, if you have a solid paper trail, I don't know why you
are concerned about this mutation. You should measure mutations against the
ancestral haplotype. You used the term "modal," which means the most
frequent value. The better method is to determine the ancestral haplotype
through careful comparison of lines of descent. An example may help. Suppose
the MRCA had three sons. The first two sons matched the father, while the
third had mutation in a marker. However, the third son had twelve sons while
the first two only had three combined. When you test males today, you may
end up sampling many more descendants of son #3. If you search for the modal
value, it will be the mutated value of son #3 rather than of his father. If
you search for the ancestral haplotype using all of the information, you can
determine with a high degree of certainty the true ancestral haplotype.
Thanks,
Phil Goff
----- Original Message -----
From: <>
To: <>
Sent: Tuesday, November 29, 2005 6:24 AM
Subject: Re: [DNA] YSNP testing, hobby scientist forces, convergence, and
back mutatio...
> In my Stephens line I have two living tetsed males who arfe descendants
> MRCA
> Elias b 1801 Stephens 4 generations ago. These two tested males are
> matching
> 23/25 indicating something happened to their haploytypes within four
> generations. As a newbie I don't know hoiw to analyze just what happened
> and when
> since 3 of the four generations are deceased and no DNA test will be done
> on
> them but it sure would be nice to know that just for family interests sake
> if
> nothing else for an actual example of a very recent changing marker
> pattern. It
> is possibble to test the 3 generations that are deceased but that will not
> happen.
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