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Archiver > GENEALOGY-DNA > 2005-10 > 1130724916


From: Thomas Krahn <>
Subject: Re: [DNA] Autosomal DNA /yDNA/ Question..
Date: Mon, 31 Oct 2005 03:15:16 +0100
References: <BAY21-F48072FD2F7F84755AA5F6E46C0@phx.gbl>
In-Reply-To: <BAY21-F48072FD2F7F84755AA5F6E46C0@phx.gbl>


Nelda Percival wrote:

> If the Autosomal DNA is used in parental testing as it was stated of a
> child (male or female) then Is it the distance (time) from the male
> that confuses the results.. (Please remember. I'm still learning..)

Autosomal markers get "diluted" in every "generation" (better
transmission event) by statistical 50%.
In a trio case paternity test (father/mother/child) we know already 50%
of the alleles, because they match with the mother. So it's easy to
identify the alleles that must match the father. In a deficiency case
(father/child) we know at least that one of the two autosomal alleles
from the child must match one of the alleles of the father. But starting
from the next transmission event (grandparents or silblings) we get
situations where alleles may or may not match and we can't make clear
exclusions from that. OK, statistical calculations are possible, but I
don't think that they are of any use in the < 40 markers range.

>
> ADDITIONAL QUESTION.. Is the introduction of the XYSTR markes in the
> near future? Why or Why not?
>
At first I try to get XSTR introduced in DNA genealogy. This is quite
new anyway.
XYSTR markers do exist. If there is a demand on them we can start
offering them.
However, everything makes only sense with an open DNA database where
such markers can be added.

Thomas

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