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From: "Diana Gale Matthiesen" <>
Subject: Re: [DNA] SNP Breakthrough for I1*-AS
Date: Fri, 26 Nov 2010 16:09:56 -0500
References: <455998.6672.qm@web113308.mail.gq1.yahoo.com><003101cb8d8b$8c16b4e0$c2482dae@Ken1> <009301cb8da1$d956b320$8c041960$@dgmweb.net><00df01cb8da4$e8ecd820$c2482dae@Ken1>
In-Reply-To: <00df01cb8da4$e8ecd820$c2482dae@Ken1>


SNPs make up less than 1% of the human genome:
http://las.perkinelmer.com/content/snps/genotyping.asp

Yes, that's still a lot of SNPs, because the human genome is huge, but now we'd
be quibbling about whether or not a fraction of 1% is "rare." If SNPs are not
comparatively rare, making them difficult to find, why is finding one such a
"breakthrough"?

> -----Original Message-----
> From: [mailto:genealogy-dna-
> ] On Behalf Of Ken Nordtvedt
> Sent: Friday, November 26, 2010 3:03 PM
> To:
> Subject: Re: [DNA] SNP Breakthrough for I1*-AS
>
>
> ----- Original Message -----
> From: "Diana Gale Matthiesen" <>
>
> If there is
> > just one form, the locus isn't polymorphic, which is the case for most
> > loci, hence the difficulty in finding the rare ones that are
> > polymorphic.
>
> Where did you get the idea most loci are monomorphic? The probabilities say
otherwise.
>
> The reason we have just several hundred snps in the y tree is because the
search has
> been very limited, and we have looked at only several tens of thousands of
males.
>
> Most every one of the 25 million or so useful loci on the y is polymorphic in
the whole y
> tree from genetic Adam.
>
> How many males have been born in the world in the last few decades --- more
than a
> billion. With the probability of any loci mutating in a father son transition
being 2 or 3
> divided by 100 million, every loci had an excellent chance of mutating in just
this
> modern era. Of course the actual mutation rate of loci probably vary above
and below
> the average rate, so some very stable sites may require a little deeper look
in the y tree
> to find their mutations.
>




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