Figure 4.

Photomicrograph of S-phase labeled Apl (left-hand top) and Aunc (left-hand bottom) in the adult rhesus monkeys testis removed 3 h after an i.v. bolus of BrdU.

The undifferentiated progeny of Apl and Aunc may be recognized as label-retaining cells observed in the second testis removed 11 days later (right-hand panels). Presumably, labeled Apl and Aps in the second testis (right-hand top two panels) were derived from Ap in S-phase 11 days earlier. The parents of labeled Aunc in the second testis (right-hand bottom two panels) are less clear. Dark brown precipitate in the nuclei indicates the presence of BrdU. PAS/hematoxylin was used as the counter stain. Bar = 10 µm.