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Archiver > GENEALOGY-DNA > 2005-10 > 1128705739


From: "Eldon Wade" <>
Subject: RE: [DNA] S21+ extends from 37 markers to 48 markers.
Date: Fri, 7 Oct 2005 13:22:19 -0400
In-Reply-To: <434692A8.9010600@scs.uiuc.edu>


Doug,

Thanks for enlightening me.

Eldon


> -----Original Message-----
> From: Doug McDonald [mailto:]
> Sent: Friday, October 07, 2005 11:22 AM
> To:
> Subject: Re: [DNA] S21+ extends from 37 markers to 48 markers.
>
> Eldon Wade wrote:
>
> >
> >Could someone please direct me to where I can learn about
> "point variation"
> >in STRs?
> >
> >
> >
>
>
> It's simple. The phrase was
>
> "a point variation within the region where the DYS448 primers
> usually lock on"
>
> Which translates into ordinary genealogy-dna-l-ese as "SNP"
> or "private SNP", or possibly a deletion or insertion or some
> sort of strange recombination event, all of which are
> equivalent to SNPs. If you get results for 448 from some
> companies but not others, this is almost surely the reason.
>
> To find out exactly what happened you would have to have the
> whole region sequenced.
> If the company that successfully measured 448 uses primers
> that are "outside"
> the primers used by the company that failed, it is a modestly
> feasible undertaking, though not commercially done. This
> diagram illustrates what I mean:
>
> DNA Strand:
> XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
> XXXXXXXXXXXXXXXXXX
> Primers Outside A Inside A
> Inside B Outside B
>
>
> Doug McDonald
>
>
> ==============================
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