Question

Explain sex determination in humans with line diagram.

Answer 1

A sex chromosome that carries the genes for male characters is called $Y$ chromosome and one which carries the genes for female characters is called $X$ chromosome.
We have a total of $46$ chromosomes. Half of them come from the mother and the rest, from the father.Out of these $46$ chromosomes, $44$ are autonomies and $2$ are sex chromosomes. The sex chromosomes are not always a perfect pair.
In females there are $44$ autonomies and two $X$ chromosomes, in males there are $44$ autonomies, one $X$ chromosome and one $Y$ chromosome. So the chromosomes
In woman are $44+XX$, while the chromosomes in man are $44+XY$. Let us see the inheritance pattern of $X$ and $Y$ chromosomes.
During gamete formation, the normal diploid chromosome number is halved. This is called the haploid condition. All the eggs of a female have $22+X$ chromosomes. A male produces two types of sperms-one type bears the $22+X$ composition and the other, $22+Y$. Therefore, in every $100$ sperms, $50$ have $Y$ chromosomes and $50$ have $X$ chromosomes.