Meiosis II

Meiosis II is the second cell division of meiosis, which can either start immediately after meiosis I,  without any prior DNA synthesis, or, after a brief time interval called interkinesis. Like mitosis, meiosis II follows an equational division, except in meiosis II, a haploid cell gets divided into two haploid cells. Meiosis II  is divided into four stages – prophase II, metaphase II, anaphase II, and telophase II. Prophase II is characterized by the thickening and shortening of the chromosomes. Centrioles move to opposite poles and begin to form a meiotic spindle which is followed by the dissolution of the nuclear membrane. In metaphase II, the chromosomes line up at the equatorial plane of the cell. Unlike in mitosis, the sister chromatids constituting each chromosome are non-identical  as they underwent recombination in meiosis I.  In anaphase II, the cohesin complex that holds the two sister chromatids together, breaks down, allowing single chromatids to move towards opposite poles. Like homologous chromosomes in meiosis I, these sister chromatids also undergo independent assortment and contribute to the production of the genetically unique gametes. Telophase II is marked by the reformation of the nuclear envelope and decondensation of the chromatids. Finally, cytokinesis divides each parental cell into two haploid cells. These haploid cells can act as gametes in sexual reproduction in animals or as spores in plants, with their unique genetic makeup helping to increase the genetic diversity.