GENEALOGY-DNA-L ArchivesArchiver > GENEALOGY-DNA > 2010-02 > 1266482946
From: Sasson Margaliot <>
Subject: Re: [DNA] "counting mutations" versus "GD from the modal"
Date: Thu, 18 Feb 2010 10:49:06 +0200
> Here is quite a bit of J1 Cohen data
> on the haplogroup J project at
> in the subgroup J1e Cohanim, P58+, L147+, L222-, YCAII=22-22.
> Is that the data that you used for your analysis?
1) I didn't do the analysis. I just heard about it being done.
2) The Project you mention has a lot of data on both J1 and J2,
and it is already analysed into various important sub-clusters.
3) It is not the same thing as a J1 part of database of samples
collected from Cohens.
4) In my opinion the J2 part of J database that is
On Thu, Feb 18, 2010 at 9:05 AM, Tim Janzen <> wrote:
> Dear Sasson,
> I think you bring up some good points below. One of the issues with
> intraclade TMRCA estimates using the variance method is that a dominant
> closely related group of haplotypes can "swamp" the data from one or more
> distantly related haplotypes. If you have a group of say 100 haplotypes
> 95 of them are from descendents of a common ancestor who lived 1400 years
> ago and the other 5 are from a branch that shares a common ancestor who
> lived 4000 years ago then the data from the 95 haplotypes will skew the
> intraclade TMRCA estimate to be much lower than the true TMRCA if all 100
> haplotypes are included in the same dataset. The right thing to do in this
> situation would be to choose 5 or fewer random haplotypes from the group
> that descends from a common ancestor who lived 1400 years ago and pair
> haplotypes with the other 5 are from a branch that shares a common ancestor
> who lived 4000 years ago for an intraclade TMRCA estimate.
> One way to spot clusters of closely related haplotypes is to check
> their genetic distances. This can help give information about clusters of
> haplotypes that might be skewing the TMRCA estimate lower. Analysis of the
> underlying tree structure such as Anatole is doing is also another way to
> get at this same information.
> This whole issue will become less and less of a problem as we get
> more complete Y chromosome sequences that help us better determine the Y
> structure in haplogroup J1 and other haplogroups. Then we can group these
> haplotypes in smaller and smaller clusters.
> I would be interested in taking a look at the J1 Cohen data if it is
> available. There is quite a bit of J1 Cohen data on the haplogroup J
> project at
> the subgroup J1e Cohanim, P58+, L147+, L222-, YCAII=22-22. Is that the
> that you used for your analysis?
> Tim Janzen
> -----Original Message-----
> [mailto:] On Behalf Of Sasson Margaliot
> Sent: Wednesday, February 17, 2010 9:06 AM
> Subject: Re: [DNA] "counting mutations" versus "GD from the modal"
> Let me give a specific example: the collection of J1 Cohens. It was fed to
> Generations2, returning 2300 years. Then it was examined according to
> Anatole's method, and it was discovered that the set has a prominent
> sub-set corresponding to a branch which is 1400 years old. The MRCA of
> the rest is more like 4000. All numbers are approximate, but the situation
> is precisely clear.
> You see, all the extra-precision of Generation2 algorithm didn't help at
> This is the famous Cohen problem, which is in the center of attention for
> more than ten years, the last 15 years, of hobbyists and academics alike -
> but it was ONLY possible to receive the right results by subjecting the
> to Anatole's method.
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|Re: [DNA] "counting mutations" versus "GD from the modal" by Sasson Margaliot <>|