Mention the total number of chromosomes along with the sex chromosomes that are present in a human female and a human male. Explain how in sexually producing organisms the number of chromosomes in the progeny remains the same as that of the parents.
Human beings have 46/23 pairs of chromosomes out of these 22 pairs/44 are autosomes and 2 or ore pair are sex chromosomes. In male, there are XY sex chromosomes. In female, there are 2 × 13 as sex chromosomes.
Sexually reproducing animals produce haploid gametes by meiosis. These gametes unite to form diploid zygote that gives rise to individual so the chromosome number remains same in parent and progeny.
Both parents contribute equal DNA material to progeny. Every sexually reproducing organism bears two sets of all genes, one inherited from each parent. Each germ cell have only one gene set. So male gamete and female gamete carry one gene for each characteristic from gene pairs of parents. But when a male gamete fuses with a female gamete during fertilisation, they make a new cell the zygote with a full set of genes. Therefore, zygote grows and develops to form a new organism having equal characteristics and chromosomes from’ both parents.