[1] Male gametogonia which are located within the testes during development and adulthood are called spermatogonium (plural spermatogonia).
[1] Female gametogonia, known as oogonium (plural oogonia),[1] are found within the ovaries of the developing foetus and were thought to be depleted at or after birth.
[3] Mice and other mammalian species undergo epigenesis during development,[3] where germ cells are separated from the somatic lineage during early gastrulation,[5] occurring at embryonic day 7 in mice,[7][8][5] and are derived directly from proximal epiblast cells relative to the extraembryonic ectoderm.
[8][5] The germ cell population (~40 in mice), after specification, migrate to the developing gonads [7][8] where they differentiate further into gametogonia.
[9] Animal models are an effective research tool due to the commonality of sexual reproduction which is thought to have same or similar mechanisms across species.
[10][5] The germ cells are bipotential in that prior to migrating to the gonads, they are capable of forming either spermatogonia or oogonia.
[10][5] The specification into either female or male fates for the organism itself also depends on the development of the gonads, which have yet to differentiate into ether ovaries or testes.
[10] In the ovary, after mitosis, the gametogonium undergo meiosis, which is initiated by intrinsic competence factor DazL and extrinsic retinoic acid, excreted by the mesonephros.