Chiasmata appear as evidence that crossing over has occurred. Neither synapsis nor crossing over occurs.
Individual chromosomes line up on the metaphase plate.
I separates pairs of chromosomes. Centromeres do not divide and sister chromatids of each chromosome move together to the pole of the cell. Mitosis separates sister chromatids of individual chromosomes. Centromeres divide and sister chromatids move to opposite poles of the cell. V. Sexual life cycles produce genetic variation among offspring Meiosis and fertilization are the primary sources of genetic variation in sexually reproducing organisms.