Archiver > GENEALOGY-DNA > 2005-06 > 1119341403

From: Thomas Krahn <>
Subject: Re: [DNA] Double peak for DYS 19
Date: Tue, 21 Jun 2005 10:15:11 +0200
References: <42B745D5.9022.127AE45@localhost>
In-Reply-To: <42B745D5.9022.127AE45@localhost>


duplications sometimes happen on the Y chromosome. DYS19 seems to be
prone for that mechanism, because most duplications have been found at
this marker. Have a look at the Butler presentation on page 15f for a
discussion about locus duplication and deletion:

How can this happen and what mechanism is behind this?

Recombination might be responsible again. Schoske and Butler have found
duplications of DYS19 flanking regions in other parts of the Y
chromosome. See:

They are very similar to the DYS19 sequence, but they don't contain the
(GATA)n repeat motive. If the sequence is very similar, by a
recombination process the real DYS19 repeat could have been copied to
the region with the similar flanking regions. Now both regions contain a
real (GATA)n repeat. This could happen more frequently than we think,
because we still observe just a single peak in this marker system.

Later, in a second step, a frame shift mutation can happen in one of the
DYS19 duplications. Then one repeat becomes (GATA)n+/-1 and we observe
two peaks in the electropherogram. That's why most of the observed
duplications are only one repeat unit spaced from each other.

This recombination process could explain, why duplications happen more
frequently at DYS19 than on any other locus.

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

> We have two PARKERs who have double peaks
> for DYS 19 (394). The values are reported as
> 14 + 15. The first result was from Relative Genetics
> in January, the second was returned from FTDNA today.
> Does anyone else have this result in their project?
> Any idea of how rare it may be?
> Dennis West
> PARKER DNA coordinator
> ==============================
> Search the US Census Collection. Over 140 million records added in the
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