Final answer:
The correct option is 3. To find out if two wingless Drosophila mutations are allelic, a complementation test should be performed. This cross will reveal if the mutations are in the same gene or in different genes, based on whether the offspring show the mutant or wild-type phenotype.
Step-by-step explanation:
To determine whether two mutations in Drosophila that result in the absence of wings are allelic, you should perform a complementation test. This test involves crossing two individuals, each homozygous for a different mutant allele. If the mutations are in different genes (non-allelic), then the offspring will likely show the wild-type phenotype because each parent provides a functional copy of the gene that the other lacks. However, if the mutations are in the same gene (allelic), the offspring will exhibit the mutant phenotype since neither parent can provide a functional copy of the gene.
A reciprocal cross is used to determine if a trait has a maternal effect, while testcrosses can be used to determine if an individual with a dominant phenotype is homozygous or heterozygous for that trait. Dihybrid crosses are performed to study the inheritance of two different traits and to determine if the genes for those traits assort independently.
Correct Option in Final Answer
The appropriate method to determine if two Drosophila mutations without wings are allelic is to perform a complementation test.