DNA Research #DNA Re: Ancestry DNA #dna


rayvenna@...
 

Adam,

You're correct, but as with everything else in science, accuracy will
increase with the number of data points. If your triangulation consists
of a number of known points, then you can give the results more weight.

For example, if I want to see if someone is related to me on my paternal
side or my maternal side, I'll compare them against at least 10 people
who share my paternal DNA but not my maternal side, then do the same for
my maternal size. If that person matches at least half of the people on
the paternal size and none on the maternal side, I'll feel confident
that the match is through my paternal side. I'll then repeat the
process against various paternal branches in an attempt to narrow things
down to a specific part of the paternal tree. It doesn't always work,
but I've had enough successes to continue using this method.

If a kit matches the several people on both the paternal and maternal
sides, then I know without a doubt that endogamy is at play. They're
related through both sides, probably considerably farther back than the
estimates predict.

This process can become insanely expensive, but I believe it works
fairly well (as does Lara Diamond and Israel Pickholtz). I've used it
with success to identify 3rd cousins, two of which have more
traditional genealogical evidence to corroborate the relationship. I'm
still looking for traditional sources to verify the 3rd.

Thanks,
Mindie Kaplan

----- Original Message -----
From: "Adam Cherson adam.cherson@gmail.com" <dna@lyris.jewishgen.org>
To: "DNA Testing" <dna@lyris.jewishgen.org>

In regards to Arlene's triangulation post, I would like to add that
triangulation is not always as clear as one would hope. I have a pair of
dna results that I often use as triangulation guideposts. One kit is my
aunt's and the other is her paternal first cousin. One would think that
anyone that matches my aunt but not her paternal first cousin would
clearly be related to my aunt on her on her maternal side. The problem
is that even a known maternal 2nd cousin of hers also matches her
paternal 1st cousin. When you add the fact that the amount of gene
sharing among cousins of equal genealogical distance can vary
considerably, one is left with often ambiguous results. The point is of
course that dna analysis triangulations involving potential relatives
who are greater than 4 steps away (i.e. further than 1st cousins), and
especially in highly endogamous populations, are difficult if not
impossible to interpret in the absence of additional and supporting
genealogical information. Beware of isolated triangulation!

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