Re: Fruit flies and temperature sensitive mutations

[Brown_D at pcfnotes1_wustl.edu]

George Slusarczuk wrote:

I seem to remember, that one strain of "wingless" fruit flies (actually
"vestigial wing", because they do have rudimentary wings, but can not
fly) CAN produce flying offspring if the incubation temperature is high.
The same culture, when kept cooler, again produces "flightless" flies.

These have a temperature sensitive mutation--if the temperature is cool
enough, the flies may be mutant appearing, but have a normal appearance
when raised at a warm temperature; other temperature sensitive mutations
work the opposite way--they can look normal at cool temps and abnormal at
higher temps.

I had a close encounter with this phenomena when I was doing a short
rotation in a fruit fly lab as a graduate student:  my main project was to
do a couple of generations of crosses to help out another person in the lab
develop a strain he needed for an important experiment.  If you want to do
the crosses correctly, you have to separate the newly hatched male and
female flies within a certain number of hours or the females will mate with
their siblings.  However, if you put them in a cooler incubator, you get a
few more hours' grace period before they can mate, so it's easier to
collect the needed virgin females for the next mating.  I used this
chilling overnight quite often, and was distressed to find out at almost
the end of the rotation that I was getting flies with mutant wings--meaning
I'd picked the wrong flies, in retrospect because one of the phenotypes I
was following in the cross was a temperature sensitive wing mutation.....

Diane Brown
brown_d at kids_wustl.edu
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