Question

The progeny of a sexually reproducing organism is never the replica of the parents in all respects. Mention factors that cause this variation.

Answer 1

Genetic variation in sexually reproducing species arises primarily, because parental genes are shuffled into new combinations, i.e., new genotypes in the offspring. The three major sources of such variations are (1) Independent assortment of chromosomes during meiosis; (2) Reciprocal recombination of linked genes on chromosomes by crossing over in prophase-I of meiosis; and (3) Random fertilization of gametes. Hence, the progeny of a sexually reproducing organism is never the replica of the parents.