Problem: As a Drosophila geneticist, you keep stocks of flies of specific genotypes. You have a fly that has normal wings (dominant phenotype). Flies with short wings are homozygous for a recessive allele of the wing length gene. You need to know if this fly with normal wings is pure-breeding or heterozygous for the wing-length trait.
a. What cross would you do to determine the genotype?
b. What results would you expect for each possible genotype?