meiöz

Meiöz, often written as meiotic in English, refers to the biological process of meiosis, a specialized form of cell division that reduces the chromosome number by half. It converts a diploid germ cell into haploid gametes, providing the genetic material necessary for sexual reproduction and creating genetic diversity through recombination.

Meiosis consists of two consecutive divisions: meiosis I and meiosis II. In meiosis I, homologous chromosomes pair and exchange genetic material in a process called crossing over, which occurs during prophase I. This pairing and recombination increase genetic variation in the offspring. The homologous chromosomes then separate, reducing the chromosome number by half. In meiosis II, the sister chromatids separate, similar to mitosis, producing four genetically distinct haploid cells.

During prophase I, a series of sub-stages occurs: leptotene, zygotene, pachytene, diplotene, and diakinesis, reflecting progressive chromosome pairing, synapsis, and recombination. Metaphase I aligns homologous pairs at the equator, anaphase I pulls apart the homologues, and telophase I concludes the first division. Meiosis II involves prophase II, metaphase II, anaphase II, and telophase II, leading to the separation of sister chromatids and the formation of four haploid gametes.

Meiöz occurs in the germ cells of animals, plants, and fungi. In animals, it underpins spermatogenesis and oogenesis; in plants and fungi, it participates in life cycles that alternate between haploid and diploid phases. Errors in meiosis, such as nondisjunction, can lead to aneuploidies and developmental disorders.