Meiosis is a process of cell division that involves the production of gametes. The process takes place in two stages meiosis i and meiosis ii resulting to four haploid daughter cells. Non-disjuction is a condition that results from the failure of separation of sister chromatids or the homologous chromosomes during cell division. This includes failure of sister chromatids to separate during mitosis or meiosis ii and failure of homologous chromososmes to separate during meiosis i. If it occurs during meiosis ii, then the result is a germline mutation in either the oocyte or the spermatocyte.