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From: "Ken Nordtvedt" <>
Subject: [DNA-HG-I] What's an I1b1-Western SnP Worth to Us?
Date: Mon, 22 Oct 2007 12:50:52 -0600


I take the clade in yhaplogroup I which has the longest branch separating it from the rest of "I", and which presently has no defining SNP, to assess the probability of finding by deliberate search such an SNP. It is I1b1-Western, and probably separated from rest of "I" 500 generations before it's MRCA.

Taking any two random haplotypes of I1b1-Western, probability of finding an SNP unique to that clade would be 500 N m

For N = 50,000 and m = 2 / 100 million; that's probability of about 1/2 --- close enough to 1 to be interesting.

But then a third haplotype from perhaps I1b1-Dinaric would need to be tested to confirm that the newly discovered SNP was not upstream and present outside of the clade I1b1-Western as well. I'm not saying it could not have some interesting applications further upstream, but chances are it would be found redundant with already known upstream SNPs.

That looks like $400 times 3 in cost? The clades for which it should be easiest to find such defining SNPs are the clades which because of the very long branch lines leading to their MRCA are well identified by their unique extended STR haplotypes which had such a long time to develop over their long ancestral branch lines.
Give me a 67 marker haplotype and membership in I1b1-Western or not is very rarely debatable.

I see the highest need for new SNPs in dividing clades which show a star-like population explosion from their MRCA --- such as I1a or R1b1, etc.

My previous post of today made a beginning in addressing that problem. Given a decent cost now thrown out for search of 50,000 bps of ydna, I hope others contribute to the discussion and math of where such commissioned searches might make sense.

Ken


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