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Archiver > GENEALOGY-DNA > 2005-10 > 1128706215


From: "Eldon Wade" <>
Subject: RE: [DNA] S21+ extends from 37 markers to 48 markers.
Date: Fri, 7 Oct 2005 13:30:15 -0400
In-Reply-To: <006b01c5cb56$d9a28560$2497893e@Masterbedroom>


Gareth,

I certainly expected it to be much more complicated. Thank you for
clarifying that for me.

Eldon


> -----Original Message-----
> From: [mailto:]
> Sent: Friday, October 07, 2005 11:50 AM
> To:
> Subject: Re: [DNA] S21+ extends from 37 markers to 48 markers.
>
> Eldon
>
> a "point variation" is like a SNP i.e. a base change,
> insertion or deletion.
> When it occurs in the section chosen to create the primers
> for the STR the primers fail because they no longer match the
> target DNA closely enough.
> DNAH may be using different primers because they have
> different multiplexes - multiplexes are designed so that the
> possible lengths of amplified sections for different STRs
> don't overlap (or those that do are tagged with different
> colour dyes), so different combinations of STRs might require
> the primers to be changed for some of them to ensure the
> multiplexing works.
>
> A point variation is potentially useful in multicopy markers
> - the DYS464X test works for R1bs (most of them!) because
> there is a g to c mutation near enough to some copies of the
> STR to allow different primer sets to lock on to different copies.
>
> DYS448 is located in the non-duplicated centre of palindrome
> P3 which has a much larger non-duplicated section than the
> others (and fewer multicopy STRs).
>
> Gareth
>
>
> ----- Original Message -----
> From: "Eldon Wade" <>
> To: <>
> Sent: Friday, October 07, 2005 4:11 PM
> Subject: [DNA] S21+ extends from 37 markers to 48 markers.
>
>
> > I am one of the few on the list who have confessed to being
> derived at
> both
> > M269 and S21.
> > I was tested at FTDNA for 37 markers and those test results
> have been
> posted
> > for some time at Ysearch under ID SFVPS. In an effort to
> put as much
> > info as possible before the list (so we can gain insight
> into S21) I
> > ordered 23 markers from DNAH. I of course got the 11
> markers that RG
> > and DNAH tests that FTDNA does not test. Those new results
> have been
> > added to my results at Ysearch bringing me to 48 markers tested. I
> > also retested 12 of my markers that were off the modal by some
> > distance or I was particularly interested in. These included 385b,
> > 390, 391, 439, 442, 447, 448, 449,
> 458,
> > 464a, 464d, and H4. After H4 was adjusted for the lab nomenclature
> > difference, the results confirmed those I had previously
> received from
> FTDNA
> > - except for 448.
> > DNAH had the following to say about DYS448: "We have repeated your
> > test several times but were unable to get a value for
> DYS448. It is
> > likely
> that
> > a point variation within the region where the DYS448
> primers usually
> > lock
> on
> > is prohibiting them from doing so. Thus the allele is not being
> > amplified and thus detected. You may expect this to be
> found in descendants also."
> > FTDNA had reported my DYS448=15, which of course is rare, but I do
> > have a
> > 34/37 match and we do match at 448=15. To remedy this problem I
> > ordered a
> > DYS448 test from DNAF this morning.
> >
> > Could someone please direct me to where I can learn about "point
> variation"
> > in STRs?
> >
> > Eldon
>
>
>
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