Spermatogonia

Definition

Undifferentiated diploid male germ cells that reside in the germinal epithelium and serve as the stem-cell population for spermatogenesis. In arthropods, spermatogonia undergo mitotic divisions to self-renew and to produce primary spermatocytes, which then enter meiosis; this occurs in structurally diverse testicular arrangements ranging from paired tubular testes in insects to diffuse testicular tissue in some arachnids. The balance between self-renewal and differentiation is regulated by somatic support cells (analogous to vertebrate Sertoli cells) and local signaling within the gonadal microenvironment.

Etymology

New Latin, from Greek sperma (seed) + gone (generation, offspring)

Example

In Drosophila melanogaster, a small cluster of spermatogonia attached to a somatic hub cell at the apical tip of the testis divide asymmetrically to maintain the stem-cell pool while producing daughter cells that differentiate into 64-cell spermatogonial cysts.

Related Terms

• Spermatogenesis
• Spermatocyte
• Spermatid
• spermatozoon
• germ line
• Testis
• Gonad
• Meiosis
• stem cell

Usage Notes

The singular form spermatogonium is used when referring to an individual cell; spermatogonia refers to the population or plural. In arthropod literature, the term is sometimes used more loosely to include early spermatogonial stages that have already initiated differentiation; precise usage varies by taxon. Contrast with oogonia, the female germ-line stem cells. Not to be confused with Spermatogonia, the diatom genus (Chromista: Bacillariophyceae).