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Archiver > GENEALOGY-DNA > 2006-02 > 1140423044


From: "Nancy Custer" <>
Subject: RE: [DNA] 35/37 Marker YDNA Advice Requested
Date: Mon, 20 Feb 2006 00:10:44 -0800
In-Reply-To: <3e50c845.8d02d2f6.81ce200@ms08.mrf.mail.rcn.net>


Patricia,

It looks like this went unanswered unless someone replied off list.

Mutations are random and they have to happen somewhere. I (as have a lot of
other people) have made an attempt to explain the biology of mutations at
http://www.contexo.info/DNA_Basics/molecular_genealogy.htm A 35/37 marker
match (yes that means two mutations) over that distance is certainly
acceptable--especially since it is supported by a common surname and
traditional genealogy.

Using Ann Turner's mutation calculator
(http://members.aol.com/dnafiler/MutationCalculator.exe) with a mutation
rate of .002, you will find that two mutations between people separated from
a common ancestor by five and six generations respectively can be expected
in about .14679 cases--not the most common scenario but solidly possible. I
have very few exact 37/37 marker matches in my project of 50+ Dorseys. They
are not all from the same line but some are well known to each other as
cousins.

CDYa is a marker chosen by Family Tree DNA because its relative volatility
makes it potentially useful in identifying branching points of closely
related lines. Just think, if there were no mutations, we wouldn't really
learn much from DNA testing. There is a mutation at YCAIIb between my
husband and our son.

Nancy

-----Original Message-----
From: [mailto:]
Sent: Sunday, February 19, 2006 3:41 AM
To:
Subject: [DNA] 35/37 Marker YDNA Advice Requested

I would like the opinions of people who have experience in
analyzing DNA as it is applied to genealogy. I know that the
expertise from this group is far above my level. However, our
family genealogy is stymied, and we would greatly appreciate
advice and comments.

We have a 35/37 marker test result for which we need
some clarification as to the possibilities of relationship within 6
generations of the Most Recent Common Ancestor (same
surname).

Paper genealogy shows that "A" and "B" were brothers in the
mid 1700's.

There is an exact match of 37/37 markers for same surname
"C", a five generation descendent (177 years) of "A", and same
susrname "D", a five generation descendent (169 years) of "B"

But, my question is about "E". Paper genealogy indicates
that "E" is a 6 generation descendant (189 years) of "A".
However, "E" only matches "C" and "D" 35/37: with marker 447
one point different and marker CDYa one point different. Could
this be due to mutation? Do mismatches for either of these two
markers have a special significance (slow or fast changing,
etc.)?

What are the chances that "E" is related to "C" and "D" and
that "A" is the MRCA of "E" as indicated by the paper
genealogy?

Thanking you for your advice,
Patricia


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