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Archiver > BRETHREN > 2006-11 > 1162513936


From: Phil Ritter <>
Subject: Re: [BRE] Free DNA testing
Date: Thu, 02 Nov 2006 16:32:16 -0800
References: <6.2.5.6.2.20061101193401.028b5bd0@stanford.edu><000901c6fec4$7a318a70$6401a8c0@thomas01>
In-Reply-To: <000901c6fec4$7a318a70$6401a8c0@thomas01>


Bill,

I suppose you could claim one does not actually have the y-chromosome
of one's patrilineal ancestor, because the actual molecules in the
string of DNA that make up that chromosome have changed over time in
the process of duplication. However people say things like "he has
his grandfather's ears" all the time without a problem (even though
we know that no one took the ears off of a person and stuck them on
his grandchild). So in the case of the y-chromosome (which is passed
down directly after being replicated in the body of each paternal
ancestor), I would have no problem saying I have John Ritter's (my
documented ancestor who lived 1770-1826) y-chromosome. If John
Ritter were the great-grandson of Hans Georg (which is likely but
unproven), then I would also have Hans Georg's y-chromosome, in at
least the commonly used sense. Where we agree is that the
y-chromosome test cannot prove this beyond doubt, but can only
disprove or add to the body of positive evidence. This is also true
of most traditional genealogy sources when one gets back into the
1700's. Like you, I would caution against expecting or demanding too
much of DNA testing. However it (specifically y-chromosome testing )
can be an extremely useful tool that has already helped solve a few
of the many genealogical puzzles in my own family tree.

I'm having a bit of hard time following you regarding the 1/256 and
intermarriages, since recombination does not affect the
y-chromosome. I think you are still talking about autosomal DNA (the
other chromosomes). We have 128 potential male ancestors at the 8th
generation but only one supplied our y-chromosome. You either have
the y-chromosome of your straight-line paternal ancestor (or should I
say a replicated copy of your paternal ancestor's y-chromosome?) or
you do not--and if you do not then that person is not really your
biological paternal ancestor.

I first did the y-chromosome test, along with a distant cousin,
because I curious as to whether my great-grandparents (Abraham Ritter
and Mariah Hamman, granddaughter of Elias Ritter) were related (both
were children of Brethren preachers, in case the moderator is
wondering if this has anything to do with the list topic). We found
that my two distinct Ritter ancestors did not share a common Ritter
ancestor and their surnames had two different origins. Fortunately
for me, the markers on the y-chromosome that I possess are relatively
rare, and the only near match I have in the FTDNA database
(containing tens of thousands of participants, including 24 Ritters)
is to the documented descendant of Hans George Ritter--a Ritter who
still lives in the Exetor area of Berks County where Hans George
settled. The Sorenson data base is more limited, with 15,000
y-chromosome records so far (including 3 Ritters); and I have no near
matches there.

A version of an article that I wrote summarizing DNA uses in
genealogy can be found at
http://www.stanford.edu/~philr/Hamman/DNAforFamilyHistory1.html (it
needs some updating regarding testing companies and costs, but the
main points remain unchanged). FTDNA's website is at
http://www.familytreedna.com.

Phil

At 01:18 PM 11/2/2006, you wrote:
>Philip:
>
>In regard to your comments below. First off, you don't have the DNA of Hans
>Georg Ritter. You have a DNA match of someone who you believe is descended
>from Hans Georg Ritter. Even though those tested have the name Ritter,
>(assuming for the sake of argument you are talking eight generations, since
>the Miller I spoke of was from the same period), they are still only 0.4%
>(1/256) of Georg Ritter. The matches could be from another family,
>recognizing the fact you have 127 male family lines to consider. This is
>especially the case with Amish/Mennonite/Brethren families who constantly
>intermarried among church members. As you note, even if they are valid
>Ritter matches, they may not even be from Georg, but a brother or a cousin.
>
>
>My point is that the more generations you go back, the more uncertainty you
>incorporate into the process. DNA is very accurate in validating that you
>are not related to a family line, but the accuracy of identifying a specific
>relation from 200 years ago is a different story.
>
>Bill Thomas

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