Question

Drosophila flies with XXY genotype are females, but human beings with such genotype are abnormal males. It shows that
A. Y-chromosome is essential for sex determination in Drosophila
B. Y-chromosome is female determinating in Drosophila
C. Y-chromosome is male determining in human beings
D. Y-chromosome has no role in sex determination either in Drosophila or in human beings

Answer 1

Correct Answer - C
In human beings, the presence of a Y-chromosome is required for the development of a male sex phenotype. X-chromosomes pesent in any number. (XXX, XXXX) in the absence of a Y-chromosome gives rise to female.
Presence of even a single Y-chromosome confers maleness. In Drosphila, Y-chromosome plays no significant role in sex determination. In Drosophila male determines were located on autosomes. One X and two autosomes produce male while two X(X, X) and two autosomes produce female.