Chromosomes are divided into two groups based on characteristics.
(i) Autosomes: All the chromosomes present in the body cells of organisms are called autosomes. The number of autosomes is 22 pairs or 44. It does not carry hereditary characteristics.
(ii) Sex Chromosomes: Chromosomes which determine the sex of an organism are called sex chromosomes. Sex chromosomes are called allosomes/heterochromosomes. The number of sex chromosomes is one pair or 2. X and Y.
In 1891, the scientist Henking observed that certain elements of the nucleus were involved in the production of spermatozoa in insects. He named it X-body. It is recognized as the X chromosome in sex determination. Later another sex chromosome was discovered in males. It is called Y chromosome. Sex chromosomes can be carriers of color blindness or hemophilia. This problem is called Sex Linked Inheritance.