Fig. 5. Meiosis. In the first meiotic division, homologous chromosomes line up parallel to each other at the equatorial plane (A). Crossing over occurs between two of the sister chromatids (B), permitting the exchange of corresponding chromosomal segments. Reduction division results in daughter cells (C) that contain only one chromosome of each homologous pair. The second meiotic division produces daughter cells (D) with just one chromosome from each homologous pair, the haploid number. Here they are shown as chromatids, each one representing a different “arm” of the 4-armed homologous chromosome pair formed at the beginning of meiosis.