GENEALOGY-DNA-L ArchivesArchiver > GENEALOGY-DNA > 2009-08 > 1251137034
Subject: Re: [DNA] Expected autosomal block sizes
Date: Mon, 24 Aug 2009 14:03:54 -0400
> Each mother will scramble her two X chromosomes
> before passing one on to her offspring.
I probably should not have used?the word "scrambled" in this context.
Scrambled is how my brain feels sometimes. The recombination
event is like a very poor first attempt at shuffling a deck of cards.?
The cards seem to stick together in blocks. The size of the
blocks is quite variable.
When a block is shared with someone else it is like a
segment in a patchwork quilt. You could share with
someone who does not share your most common ethnic group.
In fact you could share with someone totally unexpectedly
and not usually with those who have the highest total genome sharing.
False positives and false negatives seem to be occurring but
a handful of people have found common ancestors.