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Archiver > GENEALOGY-DNA > 2006-07 > 1154162179


From: Thomas Krahn <>
Subject: Re: [DNA] DYS 464 - recombinational loss of heterozygosity (recLOH)event?? (new SMGF results)
Date: Sat, 29 Jul 2006 10:39:33 +0200
References: <75BDFBB9-8FDA-4F82-88D5-719568F734DE@mac.com>
In-Reply-To: <75BDFBB9-8FDA-4F82-88D5-719568F734DE@mac.com>


wrote:

> In researching the new additions to SMGF, I reentered my search data
> & came up with much the same results, but now with the newly added
> DYS 464 markers. I have previously posted that my Scots modal
> haplotype (48markers - FTDNA37 + RG43) has one very close match at
> SMGF with a Norwegian R1b1c haplotype (i.e., a matching haplotype
> with a strongly Norwegian pedigree). Prior to the addition of DYS
> 464, the only marker which did not match was H4, with a one step
> difference between us. The DYS 464 results for the Norwegian
> haplotype are quite unusual - a single peak, i.e. - DYS 464 a,b,c,d =
> 15, 15, 15, 15. My initial reaction is that this "must" represent a
> recLOH event. Are there any other reasonable possibilities? If it is
> in fact a recLOH event, what are the implications? Is it "possible"
> that in past generations these two haplotypes were in fact a match
> prior to the recLOH event? I will concede to being too lazy to do the
> homework. This has been the subject of much discussion, & I am hoping
> to elicit the expertise of anyone who may have lately given the
> subject some expert attention. The TMRCA calculator at SMGF shows a
> probability of 50% within the past 12 generations & 90% within the
> past 25 generations. With the large margin of error associated with
> TMRCA algorithms, that puts the match within the realm of a
> (possibly) genealogically relevant time frame. I have compressed the
> link to the SMGF results using the TinyURL website -
> http://tinyurl.com/zo2u3 Thanks for the help, Pat Tagert - ysearch ID
>
Dear Pat,

A recLOH can absolutely not be excluded. If you look at DYS459 you will
see that there are two distinct alleles in both family lines (9-10) so
this can't be a deletion. Also there must be 2 DYS464 alleles at once
involved in the recLOH because the alleles 17 and 18 were both changed
to 15. This corresponds exactly to a recLOH in the alternative
conformation of the P1/P2 palindromes as shown on my palindromic map:
http://www.dna-fingerprint.com/modules.php?op=modload&name=Downloads&file=index&req=getit&lid=55

A very nice proof of the recLOH event would be testing the Norwegian
cousin for DYS464X, because I would expect him to be 15c-15c-15c-15c,
having a loss of your 17g allele.
If you have any chance of contacting him, I would propose this test.

Thomas

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