Gametogenesis

Depending on the biological life cycle of the organism, gametogenesis occurs by meiotic division of diploid gametocytes into various gametes, or by mitosis.

The existence of a multicellular, haploid phase in the life cycle between meiosis and gametogenesis is also referred to as alternation of generations.

It can take place either through mitotic or meiotic division of diploid gametocytes into different cells depending on an organism's biological life cycle.

[1] Animals produce gametes directly through meiosis from diploid mother cells in organs called gonads (testis in males and ovaries in females).

However, gametogonia are themselves successors of primordial germ cells (PGCs) from the dorsal endoderm of the yolk sac migrate along the hindgut to the genital ridge.

[4] Fungi, algae, and primitive plants form specialized haploid structures called gametangia, where gametes are produced through mitosis.

In some fungi, such as the Zygomycota, the gametangia are single cells, situated on the ends of hyphae, which act as gametes by fusing into a zygote.

In sexually reproducing organisms, it is a type of cell division that results in fewer chromosomes being present in gametes.

Premeiotic, post meiotic, pre mitotic, or postmitotic events are all possibilities if imprints are created during male and female gametogenesis.

During the growth of sperm cells, the male DNA is extensively demethylated in plants, whereas the converse is true in animals.

Scheme showing analogies in the process of maturation of the ovum and the development of the spermatids, following their individual pathways. The oocytes and spermatocytes are both gametocytes. Ova and spermatids are complete gametes. In reality, the first polar body typically dies without dividing.