Question

White eyes in male fruit fly is determined by a

• A. Dominant gene on X
• B. Recessive gene on V
• C. Dominant gene on V
• D. Recessive gene on X

Answer 1

The correct option is D Recessive gene on X

• The genes present on the X and Y-chromosomes are called sex-linked genes. Sex-linked genes and their related traits are further distinguished as either X-linked or Y-linked depending on which chromosome they are located.
• Wild-type fruit flies have dark red eyes, but there are recessive alleles of this eye colour gene (called the white gene) that cause individuals to have white eyes. White eyes in the male fruit fly are determined by an X-linked recessive gene, which means that the gene controlling this trait is present on the X chromosome. As a recessive trait, the white eye phenotype is masked by the presence of wild-type (red encoding) allele.
• So the correct option is D.