gametogénesis

Gametogenesis, or gametogénesis, is the biological process by which diploid germ cells develop into haploid gametes. In animals, it comprises two main pathways: spermatogenesis in males and oogenesis in females. Primordial germ cells migrate to the gonads and proliferate by mitosis to form spermatogonia and oogonia. In males, spermatogenesis proceeds continually after puberty in the testes, producing spermatocytes that undergo meiosis I and II to yield four haploid spermatozoa per primary spermatocyte; spermiogenesis then shapes the sperm cells. In females, oogenesis begins during fetal development; a finite cohort of oocytes arrests in prophase I until puberty, and typically one ovulated secondary oocyte per cycle resumes meiosis II upon fertilization, yielding one mature ovum and polar bodies. Meiosis reduces chromosome number and introduces genetic variation through recombination and independent assortment; cytokinesis is often unequal in oogenesis, producing a large oocyte and smaller polar bodies.

In plants, gametogenesis forms the male and female gametophytes: microsporogenesis and megasporogenesis generate microspores and megaspores, which develop into pollen grains and embryo sacs, respectively; the resulting gametes are produced within gametophytic structures, and fertilization restores the diploid state.

Key regulatory themes include hormonal control in animals (FSH, LH, and sex steroids) and developmental support in plants, with meiosis errors contributing to aneuploidy or infertility. Gametogenesis is central to sexual reproduction and genetic diversity.