Drosophila eyes are normally red.Several purple-eyed strains have been isolated as spontaneous mutants,and the purple phenotype has been shown to be inherited as a Mendelian autosomal recessive in each case.To investigate allelism between these different purple mutations,two purple-eyed pure strains were crossed.

If the purple mutations are in different genes (i.e.,they are not allelic) ,the phenotypic ratios in the F₁ are expected to be:

Question

Quizplus · Accepted Answer

If the purple mutations are in different genes, each parent provides a wild-type allele for the gene mutated in the other parent, resulting in all offspring having at least one wild-type allele for each gene, thus displaying the dominant red eye phenotype.

Drosophila Eyes Are Normally Red