Subject: help with a chromosome
Hi Bill,
in a Genetics paper I am curating:
Su et al., 2001, Genetics 157(2): 717--725
they use a chromosome which comes from your lab. I wrote to Stuart
Newfeld about it and he said I should ask you.
The chromosome in question is called 'Df(2L)DTD51xD52' in the paper and
is in Figure 2 of the paper. From that figure it looks like it takes
out 23A and 23B.
(in the paper they say it is described in FBrf0038632 == Gelbart, 1982,
Proc. Natl. Acad. Sci. USA 79(8): 2636--2640, but I looked and it
isn't)
We don't have this chromosome in FB but before I go and make a new
deficiency record for it I wanted to check that it isn't some funky
artificial deletion that is made up of two overlapping translocation
segregants and is just an ordinary deficiency.
ta,
Gillian
>
Subject: Re: help with a chromosome
Hi Gillian,
Scientific archeology is such fun!!
Here's what I can tell you:
>The chromosome in question is called 'Df(2L)DTD51xD52' in the paper and
>is in Figure 2 of the paper.
I haven't seen the paper, but if that's what they wrote, then
they are wrong. In Maureen Su's senior thesis, she refers
to 'Df(2L)DTD52-D51'. This is undoubtedly the correct name, and
derives from a screen that I did a long time ago (in a place
far away ...) for breakpoints in a restricted region of the
genome (distal 2L between dpp (22F1-2) and the 24E breakpoint
of In(2LR)DTD52.
The gamma-ray mutagenesis involved mutagenizing In(2LR)DTD52,
dppd-ho homozygous males and crossing them to In(2LR)DTD11,
dpphr4/ CyO females.
In the absence of a newly-induced lesion of the proper kind,
In(2LR)DTD52, dppd-ho/ In(2LR)DTD11, dpphr4 flies have
wild-type wing posture. I looked for exceptions that had
heldout wing posture, and recovered a series of these exceptions
that eventually ended up in 63 different established lines,
called In(2LR)DTD52-D1 thru In(2LR)DTD52-D63.
I can't find any notes on the cytology of these, although
I think I examined several of these ... hoping that the
rearrangements that disrupt transvection would be of the
type that broke between 22F and 24E on the In(2LR)DTD52
chromosome and that also broke distally on another chromosome
arm. Largely, my recollection is that this result obtained.
However, I haven't been able to find notes on the cytogenetics
yet. (I've moved my office twice in the interim and possibly
these notes have been misplaced or worse.)
All of the information up to now is based on my lab notebooks.
Here's some additional information that I've dredged up from
my memory ... and so is subject to all the problems of degradation,
apoptosis and revisionism:
When Jeff Sekelsky realized that he had an Enhancer of dpp
that mapped in region 23B-E, I gave him these 63 DTD52 derivatives
to cross to deletions of this region to see if any might have
lethal breakpoints in the region that would prove useful in
mapping and cloning this E(dpp), which we later renamed Mad.
He found a few (4 or so) DTD52 derivatives that died over a
big deletion of the region that included Mad. The others,
as I recall, were translocations or pericentric inversions of
the type that I had hoped for, but DTD52-D51 turned out from
complementation analysis and subsequent cytology (by Jeff or by
me?) to be a small deletion, and hence the renaming as Df(2L)DTD52-D51.
Hope this is all you need, 'cause it's all I have to tell you.
Bye,
Bill