The genetic constitution of gametes is finally decided at the anaphase-I after which each cell receives half the chromosome number, (from ' $2 n$ ' in parent cell it changes to ' $n$ ' in daughter cells.) During this phase, the two homologous pair of each chromosome separate and move toward opposite poles attached by microtubule of the spindle apparatus. These are further separated in anaphase-II, wherein the sister chromatids of each chromosome separate and move towards opposite poles. It cannot be metaphase-I or metaphase-II because during these stages, the chromosomes or chromatids, merely arrange themselves at the metaphasic plate.