Chromosomes Specific: Each kind of organism has a specific number of chromosomes. This number remains constant in all individuals of a species generation after generation. The nucleus of your zygote and each somatic cell of your body that arose from it contain 46-chromosomes. It is the diploid (2n) no. of our species homo sapiens.

Similarly frog’s species constant number is 26; and for garden pea it is 14. These-chromosomes are in the form of pairs. Two chromosomes, which are similar in their shape, size and position of centromere, make one homologus pair. So your 46 chromosomes are actually 23 pairs of homologous-chromosomes. Each member of a homologus pair is called a homologue.


One homologue of each pair comes from father’ the other homologue comes from mother. Thus every cell of your body contains two sets of 23 chromosomes each. One haploid set (n=23) is paternal is origin, which has been contributed by the sperm nucleus, while the other haploid se (n=23) is maternal which has come from the egg nucleus. These two sets of-chromosomes have provided the physical basis of your heredity.