Subject: Dp(2;Y)cb25-9 and Dp(2;Y)cb25-11
Hi Terry,
I am working on your 1989 Genetics Rsp paper
The effect of novel chromosome position and variable dose on the
genetic behavior of Rsp.......
Genetics  121:751-763 
and have a question about the cytology of the two 'carve-down'
duplications that were examined cytologically, Dp(2;Y)cb25-9 and
Dp(2;Y)cb25-11.
You say (Fig 2) that one of the breaks made in generating these falls
in h46-41A1. My question is about the second break. Do you know
whether there is any distal 2R left on the duplication? Or is the
second break so close to the telomere of 2R that no 2R euchromatin
remains?
many thanks for your help,
Rachel
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Rachel Drysdale.
FlyBase (Cambridge),
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Subject: Re: Dp(2;Y)cb25-9 and Dp(2;Y)cb25-11
Rachel,
Both -9 and -11 appear to be broken in the neighborhood of 60D. It is
hard to be precise about these, because of heterochromatinization and other
difficulties in mapping bands buried next to the chromocenter. An extra
problem arises with -9, which actually appears to have one break in 42A. If
you notice, -9 and -11 on Figure 2 of the paper actually are shown to have
uncertain proximal breakpoints, beyond the h bands. I do think -11 has a
more proximal breakpoint than -9, however. Does this help?
Cheers,
Terry
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Hi Terry,
thank you for your prompt response! Yes, it helps a lot and improves
what we can store about these duplications a great deal.
So to confirm,it sound to me like you would like to say that the two
carve-down deletion breaks are:
42A and 60D, for Dp(2;Y)cb25-9
and
41A1-41F (i.e. beyond the h bands but proximal to the cb25-9 break) and
60D, for Dp(2;Y)cb25-11
We all know how difficult it is to do cytology close to heterochromatin,
and it presents no problem to us to have a wide range in the breakpoint
estimates.
best wishes,
Rachel
\--------------------------------------------------------------
Rachel Drysdale.
FlyBase (Cambridge),
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Subject: Re: Dp(2;Y)cb25-9 and Dp(2;Y)cb25-11
Rachel,
You have it right.
Terry