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Archiver > GENEALOGY-DNA > 2005-06 > 1118452790


From: Thomas Krahn <>
Subject: Re: [DNA] DYS 385 10,11 BROWN
Date: Sat, 11 Jun 2005 03:20:38 +0200
References: <42A8904C.3070602@biotix.de> <01db01c56deb$113b0570$01fea8c0@DAVE>
In-Reply-To: <01db01c56deb$113b0570$01fea8c0@DAVE>


Dave,

Some people on this list have discovered, that there exist some very
related haplotypes that show unexpectedly high divergences in duplicated
markers. Sometimes two or more duplicated markers are involved at the
same time. The change shows often a reduction of two different a/b
alleles to two alleles of the same length.

Duplicated markers usually are located in palindromic regions, where the
flanking regions next to the repeat are very similar. Only a few bases
are different in a +/- 10000 bases area. So it is very likely that DNA
recombination can happen there. Recombination mechanisms aren't
understood completely, but it is some kind of copy phenomenon, where one
region is copied to the other region, resulting in a loss of one
variety. This is what I mean with "recombinational loss of
heterocygosity". Excuse my bad English.

You mentioned, that your haplotype was similar to R1b except for the
unusual DYS385 alleles. So maybe one of your ancestors has had a modal
DYS385 = 11/14. At a germline cell, maybe there has happened a recLOH
and resulted in a DYS385 = 11/11. Now your haplotype is only one
mutation away. You have a 50% chance that the DYS385a allele mutated to
10 or that the mutation was at DYS385b. Here you could have a closer
look with the Kittler DYS385a/b(K) test. If #11426 and #33668 are really
closely related, the orientation would be the same.

I have to agree with John Chandler, that you will not get much more out
of your specific case with a Kittler test compared to an additional
marker, but if we all observe many cases like your's we could learn more
about the recombination phenomenons. It might help you to find out more
about your relation to the other R1b folks that show the modal values at
DYS385 and maybe this could show us all something, why R1b differs in a
strange way from other haplogroups mainly at the duplicated markers in
the palindromic region.

Looking only at your duplicated markers the two kit# could be only one
recombinational step away, if DYS459 and DYS464 have a recLOH at the
same time.

kit# 385 459 464 CDY
33668: 10/11 9/10 14/15/17/17 37/37
11426: 10/11 9/ 9 15/15/17/17

However, the missmatches at the other markers are still very big.

Thomas Krahn

--
Dipl.-Ing. Thomas Krahn biotix GmbH
Tel.: +49-331 / 2300 452 Hermannswerder Haus 14
Fax: +49-331 / 2300 450 D-14473 Potsdam / Germany
http://www.biotix.de


Dave Anderson wrote:
> Thomas,
> Thanks very much for your comments about my "very rare" DYS385a,b
> results. However, I have no idea what "recombinational loss of
> heterocygosity" means.
>
> Before I get into Kittler Tests to reveal whether "10,11" is really
> "11,10" or not, can you tell me about the possible significance and/or
> usefulness of knowing the correct order?
>
> It would seem that both samples would need to be tested. That leads to
> four possible combinations:
>
> 1) Kit 11426 is 10,11 and Kit 33668 is 10,11.
> 2) Kit 11426 is 10, 11, and Kit 33668 is 11, 10.
> 3) Kit 11426 is 11,10 and Kit 33668 is 10,11.
> 4) Kit 11426 is 11,10 and Kit 33668 is 11,10.
>
> I have been told that 10,11 is "very rare". About 1/1000 individuals.
>
> Don't know about 11,10.
>
> Would appreciate any comments about the above four cases.
>
> My top priority is identifying the parents of Jonathan BROWN, Sr. who is
> the earliest identified ancestor for Kit 11426.
> Dave Anderson
>



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