1
|
Fertilization and embryonic developmental capacity of epididymal and testicular sperm and immature spermatids and spermatocytes. ACTA ACUST UNITED AC 2009. [DOI: 10.1017/s096227990000140x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Spermatogenesis in mammalian species begins after birth. The gonocytes, arrested at G2 of the cell cycle in the foetus, resume mitotic proliferation after birth. As identified in the mouse, the gonocytes migrate towards the periphery of the seminiferous cords at day 4 to day 6 after birth and are located in close contact with the basal lamina. From this stage the gonocytes are referred to as primitive type A spermatogonia. These cells continue mitotic proliferation and differentiate to form type B spermatogonia. By day 10 after birth, many of the type B spermatogonia have formed preleptotene primary spermatocytes which undergo a final phase of DNA synthesis (leptotene) prior to entering meiotic prophase (zygotene).
Collapse
|