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 of Drosophila.
B. The Y chromosome is female in Drosophila.
C. The Y chromosome is male determined in human beings.
D. Y chromosome has no role in sex determination either in Drosophila or human beings.

Answer 1

Hint:-There are two types of chromosomes- autosomes and sex chromosomes. The sex chromosomes are of two types- X and Y chromosomes. The Y chromosome determines maleness.

Complete answer:-
In the case of mammals, sex is determined using sex chromosomes. The primary sex is determined by whether an organism has an XX or an XY karyotype. Females have two X-chromosomes in all their somatic cells whereas males have one X and one Y chromosome. Individuals with a Y-chromosome will develop into a male, independent of the number of X-chromosomes. But the individual without the Y-chromosome will develop into a female. In the case of secondary sex determination, the male or female sex is determined by the hormones produced by gonads.
In the case of Drosophila, the sex of an individual is not determined by the Y-chromosome. The genes present on the Y-chromosome are responsible for sperm formation in adults. Sex is determined by the balance of autosomal alleles and the X-chromosome. A normal diploid male contains two sets of autosomes and XY-chromosomes. A normal diploid female has 2 sets of autosomes and two X-chromosomes.
Drosophila flies with XXY genotype are females, but human beings with such genotypes are abnormal males. It shows that the Y chromosome is the male determiner in human beings.

The correct answer is option C.

Note:- In the case of Drosophila, individuals of different sexes are formed based on the ratio of autosomes and sex chromosomes. They include Meta females, females, intersex, males, and meta males.