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Archiver > GENEALOGY-DNA > 2002-08 > 1028547295


From: John S Walden <>
Subject: Re: [DNA] thanks
Date: Mon, 05 Aug 2002 07:34:55 -0400
In-Reply-To: <63.f8c4a88.2a7f51ea@aol.com>


All
Reviewing the document at
http://www.journals.uchicago.edu/AJHG/journal/issues/v66n5/991495/991495.html
For us I believe one of the keys included is this quote
"Mutation-rate estimates are necessary in such paternity testing, to
assess the possibility of a potential false exclusion."

What I think this says is that in the absence of a paper record and you
wish to be really confident you make the right
decision or excluding/including when the tests are close then the 25 marker
test should be used.
Here is an example of what I think they are saying to us.
If we do a 12 marker test and we have a 5 generation time frame (4 births down
each side of the tree) then:
Markers
Tested/Match What to do
12/12 Probable match with out paper trail you must expand to
24/25 marker test
With a paper trail accept the match and test more
people.
12/11 Same
12/10 Likely a mismatch upgrade to avoid the 1 out of 20 case
of a false exclusion.
12/9 Very likely a mismatch spending the money will confirm it.
This is a 100 to one shot so only spend the money
if you
want to go from 99% to 99.999% certain.
12/8 (and less) Forget it there is NO match here.

So in the last two cases one can save the cost of testing to 24/25 markers.

If the number of generations involved goes up to 10 (9 births down each
side of the tree)
then the 100 to one breakpoint is between 4 and 5 mismatches
That is at 3, or less, test more; at 4 or 5 think about it; and at 6
differences there is no family match.
[If the people we are testing are born about 1950 and at 25
years/generation takes us
back to the early 1700s so this looks to me to be our more usual case.]

That is the way I calculate the numbers.
For Surname project managers would that make sense from what you have seen?

Thinking further on this 6 (more) out of 12 differences sounds like a lot to me
I think I will look through the Surname studies and see how often this happens.
Maybe is it so rare we should just forget about it an figure we should
spend the money and
be sure right from the start.

John W



At 11:58 PM 8/4/2002 -0400, you wrote:
>Thanks to Ann and Barbara.
>
>I've located
>
>http://www.journals.uchicago.edu/AJHG/journal/issues/v66n5/991495/991495.html
>
>and I think it is saying, "Upgrade to a 25 marker test!"
>
>Grant

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