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Archiver > GENEALOGY-DNA > 2008-11 > 1225900913


From:
Subject: Re: [DNA] 23andMe Results (attention Chia)
Date: Wed, 5 Nov 2008 11:01:53 EST


In a message dated 11/4/2008 6:33:03 AM Pacific Standard Time,
writes:

> Ann,
> What I would like to see is percentages for the upper and lower halves
> and both too for the Ancestry Painting. That would be helpful although
> I'm not sure one really knows if the upper half is paternal or maternal?
> Al


No, there's no way to tell which is which. Indeed, I'm not even sure they can
phase* a whole chromosome so that everything in one half (top or bottom)
actually belongs to one chromosome. Your genotype results are always given in
alphabetical order, so the first one listed could come from your father for one
SNP and from your mother in another SNP. The combinatorial possibilities grow
very rapidly. Anders has been working with a program called PHASE that uses
population data for comparisons -- maybe he can shed some light on this.

Phasing: Determining the haplotype phase (the arrangement of alleles at two
loci on homologous chromosomes) from genotype data using statistical methods.

www.nature.com/nrg/journal/v4/n12/glossary/nrg1227_glossary.html


Ann Turner

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