- The initial development of a nephron occurs in a nephrogenic compartment (framed). The recruitment of progenitor cells takes place in the nephrogenic niche and pretubular aggregate. The shaping of the nephron runs in the renal vesicle, comma-shaped, and S-shaped body. Traces left by damage or scheduled reduction are indicated in gray. Traces were reported from the human h, baboon b, and rodent r kidney. [–] not investigated