Archiver > GENEALOGY-DNA > 2003-11 > 1069522157

Subject: Re: [DNA] FW: Related after 3 generations?
Date: Sat, 22 Nov 2003 12:29:17 EST

In a message dated 11/22/03 9:22:41 AM Pacific Standard Time,

> I have never heard of anything this absurd.

I saw that message, too -- along with many responses. I sent the originator
the following message.

Subj: number of generations for DNA testingĀ 
Date: 11/22/03 8:30:33 AM Pacific Standard Time

Hi --

I am not a subscriber to the @@@@ mailing list, but I run the GENEALOGY-DNA
mailing list, and I have an automated search for the keyword "DNA" in other
mailing lists. That's how I spotted your post.

I suspect your nephew is referring to the type of testing done for paternity
cases, where you can absolutely prove a connection. Paternity testing uses
markers which get shuffled with every generation. It's really one specific form
of relationship testing, one that can be extended to the grandparent or first
cousin level. After that, you can't really prove anything at all as far as a
SPECIFIC relationship.

However, DNA testing for genealogy uses some special cases: the Y chromosome,
which is handed down intact through the paternal line, and mtDNA, which is
handed down intact from the maternal line. That can tell you if you have a
common ancestor somewhere in the straight male or female line, but it can't tell
you whether that happened one generation ago or many generations ago.

You may forward this to the @@@@ list if you wish.

Ann Turner - GENEALOGY-DNA List Administrator
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