Question

Explain the mechanism of sex-determination in humans.

Answer 1

Sex determination in humans is of XX-XY types. Human has total 23 pairs of chromosomes; 22 pairs of autosomes and one pair of sex chromosomes. In humans, females are homomorphic (XX) and males have heteromorphic sex chromosomes (XY). During meiosis, all the gametes produced by females contain only the X chromosome (22 A + X), whereas males produce two kinds of gametes, 1/2 gametes with X - and 1/2 with Y-chromosome (22 A + X and 22 A + Y). Fertilization of egg (22 + X) with sperm carrying 22+X chromosomes results in female child (44A + XX). Fertilization of egg (22 + X) with a sperm carrying 22+Y chromosomes results in a male child (44A + XY).