[Drosophila] Curious Incident of the Flies in the Homozygote

[Sonia Sen]

Dear All,

I was wondring if anyone could help me.

I have a stock which is such:

yhs FLP; GAD>GFP/CyOGFP; FRT82B tubGAL80/TM6B.

If I dissect out these flies which are balanced on both, I never see
GAD>GFP expression (as expected).

If I dissect out the flies that are homozygous on the third or
homozygous on both second and third I see that half of those brains
show the complete GAD>GFP expression.

The very same thing has happened to me with a very similar stock:  yhs
FLP; GH146>GFP/CyOGFP; FRT82B tubGAL80/TM6B.

I dont think that it is because GAL80 is not enough because I see
complete scilencing in the balanced flies.  Also because I have seen a
similar thing with two other stocks:  w; GH146>2XeGFP and w;
GH146>mCD8GFP.

In these stocks I never have a problem when the stock is kept
balanced, but as soon as I expand a homozygous copy of the stock into
bottles, I loose the GH146 expression.

I wanted to know if anyone has faced a similar problem and also if
anyone had any ideas as to why this was happening.

Many thanks,

Sonia.