[Drosophila] Exilixid stocks

[campus page]

My dear fly colleagues,

I've recently got some flies from exilixis collectiom at Harvard
University.
But, I am confused with these because I am finding dominant markers
such as stubble that are not shown in Flybase genotype info. in most
of the lines that i obtained for my gene. Does this mean the insertion
is heterozygous? on third as my gene is on third chromosome.

IInd question:
Once I obtain the lines shoud I outcross  (to cantonise) for example
to mitigate position effects in case if i want to qPCR compare the
gene expression with a matched control fly like w-.
Please somebody help me.

Many thanks in advance.
Best wishes.