Polytene Chromosome Squashes

William J. Etges wetges at COMP.UARK.EDU
Mon Sep 18 12:17:04 EST 1995


At  8:09 PM 9/15/95 +0000, Denise Storck-schattner wrote:
>Hi!  I am a graduate student at the University of Wisconsin - Parkside.
>I have been following this newsgroup for about a month now, and I have
>witnessed how helpful it can be to fellow Drosophila researchers.
>
>I am wondering if anyone out there knows a good way to chromosome arm
>separation when performing a squash of the salivary chromosomes.  Right
>now, I use a pencil to tap the chromosomes before squashing them firmly
>with my thumbs, but when I view them under the microscope, they are too
>bunched together, and therfore, I cannot see all the bands clearly.  I am
>following Protocol 17 in the Drosophila Laboratory Handbook by
>Ashburner.  Any help or suggestions in this process will be greatly
>appreciated.  Thank you.
>
>Denise Schattner

Denise,
                There are many ways of obtaining the best polytene preps,
you just have to experiment a little with your protocols. Try using more
thumb pressure with your slide between two sheets of blotting paper-just
don't press too hard or you'll blow the chromosomes apart. If you press
with just the right mount of pressure, the chromosomes should separate
nicely. Also try rinsing the salivary glands in 45% acetic acid before
staining. That might help. What species are you studying?

Bill

-------------------------------------------------------------------------
William J. Etges
Department of Biological Sciences
SCEN 629
University of Arkansas
Fayetteville, AR 72701  USA
wetges at comp.uark.edu
http://comp.uark.edu/~bioinfo/etges.html
voice: (501) 575-6358
FAX   (501) 575-4010

 I don't know whether to kill myself or go bowling.
................title of a country and western song.

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