Meiosis
![In meiosis, the chromosomes duplicate (during interphase) and homologous chromosomes exchange genetic information (chromosomal crossover) before a first division, called meiosis I. The daughter cells divide again in meiosis II, splitting up sister chromatids to form haploid gametes. Male and female gametes fuse during fertilization, creating a diploid cell with a complete set of paired chromosomes.](/Images/godic/202502/22/Meiosis_Overview.svg4611.png")
![A video of meiosis I in a crane fly spermatocyte, played back at 120× the recorded speed.](/Images/godic/202502/22/-Calyculin-A-an-enhancer-of-myosin-speeds-up-anaphase-chromosome-movement-1475-9268-6-1-S1.ogv4611.jpg")
![Gametic life cycle.](/Images/godic/202502/22/Gametic_meiosis4611.png")
![Zygotic life cycle.](/Images/godic/202502/22/Zygotic_meiosis4611.png")
Meiosis /maɪˈoʊsᵻs/ is a specialized type of cell division that reduces the chromosome number by half. This process occurs in all sexually reproducing single-celled and multicellular eukaryotes, including animals, plants, and fungi. Errors in meiosis resulting in aneuploidy are the leading known cause of miscarriage and the most frequent genetic cause of developmental disabilities.