Question

Explain sex determination.

Answer 1

Hint:Sex determination is the method by which the sex of an individual is decided. The sex here means male denoted by XY and female by XX.

Complete answer:
For some organisms, sex is determined by the temperature and environmental factors inside the egg. But in humans the sex is determined on the presence or absence of sex hormones. Humans contain 23 pairs or 46 numbers of chromosomes. One pair among these pairs of chromosomes is the sex chromosome. The two types of sex chromosomes are X and Y. A female contains a pair of XX chromosomes in their cell. Male contains XY that is one X chromosome and one Y chromosome in their cell. It should be noted that gametes are formed by the process of meiosis which is a reductional division. To keep the number of chromosomes constant gametes are formed by the process of meiosis and not mitosis. The male gamete is fused with the female gamete after sexual intercourse and sexual reproduction takes place.
The sex of the child is therefore dependent that which hormone the male or father will transfer; if the male transfers an X chromosome then and female will always transfer the X chromosome then the XX chromosome will make a female. But if the male transfers the Y chromosome then a boy will be born (XY).

Note: The genotypes of female and male is in Female : 46 Chromosomes = 44 Autosomes + XX sex chromosomes and in males 46 Chromosomes = 44 Autosomes + XY sex chromosomes. The division of sex chromosomes takes place by meiosis whereas that of autosomes takes place by mitosis.