Fig. 6.

Spermatogenesis in Drosophila. The stem cell niche is maintained by 12 non-dividing somatic cells, called ‘hub,’ anchored with GSCs and CySCs. The stem cell niche's maintenance is tightly regulated by a cascade of genes and pathways. Each GSC was encysted by two CySCs. Upon asymmetric division, each GSC self-renews and gives rise to gonialblast (GB), and each CySC self-renews and gives rise to cyst cells (early cysts and late cysts) that encyst the germ cells throughout the spermatogenesis until they develop into spermatids. The GB undergoes four rounds of transit amplifying (TA) mitotic divisions to produce 16 interconnected (by ring canals) spermatogonial cells that differentiate into early spermatocytes, and these spermatocytes undergo meiosis to produce 64 haploid spermatids. They then undergo elongation and coiling to become mature spermatids. The box represents the region where cytoophidia is normally abundant. Created with BioRender.com