RootsWeb: GENEALOGY-DNA-L Re: [DNA] Malaspina et al (2001)'s Cohens -- an answer ?

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Archiver > GENEALOGY-DNA > 2007-04 > 1176701001

From: Rebekah <>
Subject: Re: [DNA] Malaspina et al (2001)'s Cohens -- an answer ?
Date: Mon, 16 Apr 2007 00:23:21 -0500
References: <461F9F20.9010003@comcast.net><46223AAE.1020802@ucl.ac.uk> <462293CF.5090608@sbcglobal.net><4622B792.4080304@ucl.ac.uk>
In-Reply-To: <4622B792.4080304@ucl.ac.uk>

James, The Cohanim article is looking better these days.:-) Would you be willing to do something with the Founder effect section? Parts of it are having a nasty affect on my delicate sensibilities and I may do something rash. " Founder effect People who do not believe in the validity of the Cohen Modal Haplotype say that such efforts to detect a genetic signature's survival in the Y chromosome unchanged over 3,500 years (approximately the amount of time since the time of the patriarchs) seem misplaced. While it has been shown that surname studies and Y-DNA matches validate each other[13], the most current research increasingly points to a relatively recent historical timeframe for founder effects and matching haplotypes. According to a study by a forensic team[14], the average mutation rate for Y-STRs (the "alleles" that create differences in haplotype scores) is 2.1 x 10(-3), or once every 476 generations, i.e., once every 14,280 years. But this estimate is computed on the basis of one allele changing – on its either increasing by 1 or its diminishing by 1. Where most people err is to forget that these statistics apply to one marker. For the six markers, the approximate 50% point for one mutation would be one-sixth or 2400 years. Hence, even if Aaron's progeny did prosper and survive over the millennia, they would have split into dozens of different genealogies. Some believe that if the discoverers of the "Cohen Modal Haplotype" found any modal Jewish haplotype at all it is probably the genes of a prolific medieval rabbi who lived about 1000 years ago and had numerous sons and grandsons. Others argue that the fact that so many people with a family belief of being Cohanim have tested positive for the Cohen Modal Haplotype offers proof of its validity. The former conclusion consorts better with the emerging consensus that the roots of the human family tree are much shallower than previously believed. However, mutation rates are bitterly disputed and only longitudinal studies such as comparisons available to large DNA projects will yield secure estimates. [Surname projects are limited to recent western Christian populations and do not apply to other cultural groups.] " James Heald wrote: >> The Wikipedia article now organises the data, and has links to the >> original papers: >> http://en.wikipedia.org/wiki/Y-chromosomal_Aaron >> >> The haplogroup numbers from Thomas et al (1998) count the number >> "xDE,PR" -- ie not in Hgs D, E, P, Q, R >> >> Behar et al (2003) have a more detailed breakdown of Cohanim numbers by >> haplotype, from a slightly enlarged sample. >> >> >> The article doesn't include Bonnie's wonderful breakthrough yet, which - >> with luck - means we may be getting close to finally getting the story >> sorted out! >> -- Regards, Rebekah "And they wonder why the maples Can't be happy in their shade." Trees (Neil Peart from Rush)