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Archiver > GENEALOGY-DNA > 2010-02 > 1266771621


From: Al Aburto <>
Subject: Re: [DNA] Y chromosome SNP occuring in More than one PaternalLineages
Date: Sun, 21 Feb 2010 09:00:21 -0800
References: <mailman.6086.1266736315.2099.genealogy-dna@rootsweb.com><003701cab314$5840ccc0$f7adcbc4@saphirconsult.local>
In-Reply-To: <003701cab314$5840ccc0$f7adcbc4@saphirconsult.local>


Hi Kamel,
The X & Y chromosomes (currently) only recombine at the very tips of the
Y-chromosome. I think about 95% of the Y-chromosome doesn't recombine
with the X chromosome at all. In ages past though the X & Y did
recombine more than is seen today, but I believe those are times far far
in the past. I suppose there can be "episodes", when errors happen,
when the X & Y can recombine unexpectedly at places other than the tip
of the Y-chromosome. We would need Dr. Turner or Krahn to address this
question though.

So, with my limited understanding, I would say that "recent" SNPs in the
MSY (Male Specific Region of the Y-chromosome) did not come from the X
chromosome by recombination.

Here is a very good website on the evolution of the Y-chromosome:
http://www.hhmi.org/biointeractive/gender/Y_evolution.html ...
Al

> On 2/21/2010 8:38 AM, Kamel AL GAZZAH wrote:
> Hello
> But I wonder if the following senario is possible:
> This SNP fisrts happened in X chromosome and then it has been transmitted to
> Y chromosome tby recombining two times, which means that two Y Haplogroups
> sharing the same SNP share a common Portion of X Chromosome.
>
>
> I would like to know if this senario is possible or not ?
> What are teh portions of Y chromosome which can be coming from X Chromosome
> Recombination ?
>
> Kamel Gazzah
> J2a4h (first case of L192.2)
>


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