GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2002-12 > 1040665661


From: Jerry Smith <>
Subject: [DNA] Counting ancestors, measuring ancestry
Date: Mon, 23 Dec 2002 09:47:41 -0800
In-Reply-To: <a4.3144e95f.2b36737d@aol.com>


Some years back I recall a book (perhaps "Heredity and You"?) that said it
was possible to *not* be genetically related to a grand-parent and that by
the sixth generation back, it was around a 50/50 chance that there was a
genetic connection with any one ancestor.
It also said that most genetic material was passed along via whole
chromosomes but there was some 'cross-over' (don't remember what that was)
possible.

Is this consistent with current thinking?

If so, might not such a 'loss' of ancestors account for at least some of
the discrepancy between our family knowledge of heritage and that measured
by DNA testing (except, of course, the 'edge' --Y and Mt-- tests)?

Given that there is a fairly small number of genes (or whatever the
smallest bit of genetic information that can be passed along is), is it
reasonable to have a greater count for 'ancestors'?

Jerry Smith
in Sacramento, CA
trying to make some sense of it all...



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