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Archiver > GENEALOGY-DNA > 2005-11 > 1133222908
From: "Lowe DNA" <>
Subject: RE: [DNA] YSNP testing, hobby scientist forces, convergence, and back mutation issues -- to YSNP or not to YSNP
Date: Mon, 28 Nov 2005 18:08:28 -0600
In-Reply-To: <438B8C6A.4050303@kerchner.com>
John and Charles...
I don't see proof to the contrary on convergence and divergence...so hold
the ditto
Bill
-----Original Message-----
From: charles [mailto:]
Sent: Monday, November 28, 2005 5:02 PM
To:
Subject: Re: [DNA] YSNP testing, hobby scientist forces, convergence,
and back mutation issues -- to YSNP or not to YSNP
John:
Dittos!
Charles
John Chandler wrote:
> Bill wrote:
>>However, convergence and divergence is alive and well in our Stephens
>>cousins with 1st and 2nd cousins with a documented paper trail differing
by
>>two or more STR marker values than 3rd and 4th Stephens cousins. Of course
>>the outward mutation can be corrected back in the next generation with the
>>sons.
>
>
> You write as if there were a "master plan" which goes awry when a
> mutation occurs, but there isn't one. It is certainly possible that a
> mutation could be "corrected" in the next generation, but it's highly
> unlikely, and it's therefore not among the top ten possibilities that
> should come to mind when you think about mutations. This sort of
> belief in express cancellation of mutations has been put forward
> as an "explanation" of the seemingly low mutation rate on evolutionary
> time scales (the so-called "effective" mutation rate), but nobody has
> come up with any notion of how such a back mutation could be triggered
> (and nobody has observed such a thing, either).
>
>
>>However, haplogroup identification can only be done by SNP testing. In
fact,
>>haplogroup is defined only by SNPS. All the coded algorithms can NOT
>>accurately determine haplogroup, but an empirical deep level SNP can do
this
>>100% of the time.
>
>
> Just look at the sudden turmoil over the recent puzzling S21 results.
> Whenever SNP results are somehow surprising, people start worrying
> about lab errors, chain-of-custody problems, and the like. By the
> same token, we *know* that there are R1b men living today who have
> S21 positive through recent parallel mutation instead of ancient
> inheritance. It is unlikely to explain the existing situation, but
> it's not impossible. Therein lies the fundamental weakness of SNP
> testing -- too much is always riding on ONE test that humans are
> of necessity running.
>
>
>>It is time to have SNP tests written into all 12 marker
>>tests...Let's get rid of "guesstimation" altogether as all of us here
>>are looking for facts...not statistical assumption.
>
>
> The facts that most of us are looking for are genealogical, rather
> than anthropological. SNP testing, as presently constituted, is
> *much* less valuable than any kind of STR upgrade on the market.
>
>
>>So why recommend a basic, and later a deep level, SNP for every male
>>tested....
>
>
> Good grief!
>
>
>>(6.) To hopefully provide a "time estimate" for SNP sub-clades (to date
all
>>my 9 Hap-Q SNPs)
>
>
> Sorry, but that is exactly backwards. Assigning dates to mutations is
> extremely difficult and error-prone, and the only way to be sure of
> getting it right is to start with a reliable genealogy that extends
> all the way back to the person who experienced the mutation in the
> first place and then to test descendants of him and of his brother(s).
> In other words, genealogy will be the tool that sets the timing and
> meaning of truly deep-level SNPs.
>
>
>>I always remember John Chandler's salient advice to me... STRS can NOT
>>determine kinship, however the can determine who is NOT related.
>
>
> Ah, but relatedness is a continuum. Whenever STR testing *fails* to
> determine that two people are unrelated, that means they are, after
> all, related (or at least probably related). In many cases, that's
> the necessary precondition for going out and doing the genealogical
> research to prove the exact degree of kinship.
>
> John Chandler
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