Meiosis undergo a second form of cell division that makes the sexually-reproducing
organisms reproduce cells with half the number of chromosomes.
This results to a
mixing or shuffled of the homologous pairs, a tendency of crossing
over that causes exchanges of alleles on the homologous pairs and random fertilization unites different combinations of maternal
and paternal chromosomes, which means that when zygotes are formed, the
gene combination will be different each time, even if they come from the same
two parents.
