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Archiver > GENEALOGY-DNA > 2012-02 > 1329024440


From: "Tim Janzen" <>
Subject: Re: [DNA] autosomal DNA
Date: Sat, 11 Feb 2012 21:27:20 -0800
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In-Reply-To: <49DE1EA1-B5CA-4754-BF2E-9A50016DCC24@verizon.net>


Dear Jim,
I would agree with you that many blocks will keep their size for
some small number of generations, but the largest blocks (and even some of
the smaller blocks) are continuously being split by crossovers with each
generation. I thus don't think that we can say that segments in the 7-10 cM
range seem to have a high likelihood of remaining as contiguous segments
over a larger number of generations (say 10 or so). The number of
crossovers per generation stays constant. The smaller the segments become
the lower the chance that any one segment with have a crossover in it during
any one generation.
Sincerely,
Tim Janzen

-----Original Message-----
From:
[mailto:] On Behalf Of Jim Bartlett
Sent: Saturday, February 11, 2012 9:12 PM
To:
Subject: Re: [DNA] autosomal DNA

I think we'll find it's some of each. Large blocks don't necessarily get
smaller with each generation - some keep most of their size for some
generations. On the other hand, some tend to be quickly chopped up. As more
phasing is done and we can follow segments through more than one generation,
we'll gradually learn more. This is an exciting journey.


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