Apterous × Dumpy cross produces wild-type offspring

[Munki]

I've been conducting some genetics experiments for my Bio/Genetics class and in the most recent one I got some suprising results.

I did a cross between Apterous (wingless) flies, and Dumpy (misshappen wings) files. The offspring of the experiment had Wild (normal) wings. I can't explain this occurrence. I would think that one allele would be dominant over the other, but instead, I get an entirely different trait.

Can anyone help me explain these results, or at least point me in the right direction? I've already thought of the experiments being compromised, but I've done it several times, and I keep getting the same results. I have yet to do an F2 generation.

 

[gerben]

Perhaps only the flies that are homozygotic for Apterous or Dumpy get the trait. So you crossed AA flies with DD flies which would give you F1 flies that were all heterozygotic AD.

In the F2 generation you will get Apterous and Dumpy flies as well as normal flies. I guess you know what percentage of each to expect if this the case.

 

[Monique]

Maybe you complemented the genes? Meaning that the apterous and dumpy phenotypes are due to gene defects in different pathways, so by crossing them they regain a functional copy of the gene and loose their phenotype.