Question

Male child is born when zygote has

• A. X chromosome
• B. Y chromosome
• C. XX chromosome
• D. XY chromosome

Answer 1

The correct option is D XY chromosome

Human follows XX- XY mechanism of sex determination. Human females have 46 chromosomes arranged in 22 homologous and homomorphic autosomes and two copies of X chromosomes as sex chromosomes (44+XX). Males have 22 homomorphic pairs and one heteromorphic pair, the XY pair (44+XY). During meiosis, all the gametes produced by females contain only the X chromosome (22 + X), whereas males produce two kinds of gametes, 1/2 gametes with X- and 1/2 with Y-chromosome (22 + X and 22 + Y). Fertilization of egg (22 + X) with sperm carrying 22+X chromosomes results in female child (44 + XX). Fertilization of egg (22 + X) with the sperm carrying 22+Y chromosomes results in a male child (44A + XY) as the zygote is a diploid structure and consists of two complete sets of chromosomes. Thus, the correct answer is option D.