Spermatocytes

Spermatocytes are male germ cells within the seminiferous tubules of the testes that arise from spermatogonia and proceed through meiosis as part of spermatogenesis. There are two main classes: primary spermatocytes and secondary spermatocytes. Primary spermatocytes are diploid cells (2n) that form after mitotic divisions of spermatogonia and enter the first meiotic division (meiosis I) in the adluminal compartment of the seminiferous tubules.

During meiosis I, homologous chromosomes separate, producing two haploid secondary spermatocytes (n). Each secondary spermatocyte then undergoes meiosis II, in which sister chromatids separate, yielding four haploid spermatids per primary spermatocyte. Spermatids subsequently undergo spermiogenesis to become mature spermatozoa.

Spermatocytes are located within the seminiferous epithelium and are supported by Sertoli cells, which provide nutrients and regulatory signals. The process of spermatogenesis begins at puberty and continues throughout life in most males. Meiosis in spermatocytes introduces genetic recombination and independent assortment, increasing genetic diversity of the resulting sperm.

In humans, primary spermatocytes carry 46 chromosomes; after meiosis I and II, the resulting spermatids contain 23 chromosomes, one chromatid each. Abnormalities during meiosis in spermatocytes can contribute to infertility or congenital anomalies if aneuploid gametes form.