FIGURE 3.

(A) Germ cells survive beyond birth in male Dazl null animals with an outbred genetic background (C57Bl/6 × CD1) but not inbred C57Bl/6. Testes were taken at 1 d post partum and stained with anti-Mvh antibody to detect germ cells (red) and counterstained with DAPI (blue). (B) Germ cell survival in outbred Dazl null male mice. Testes were taken at varying times after birth, fixed, and stained with anti-GCNA antibody. The percentage of tubules present containing GCNA-positive cells (brown staining) was determined for individual animals. (C) Representative images showing GCNA-positive cells in Dazl ^+/+ and ^−/− animals with C57Bl/6× CD1 genetic background. Meiotic progression appears normal up until 7 d pp for those germ cells that remain in the null animals. From 10 d pp onward, GCNA-positive cells remain at edges of tubules and/or appear apoptotic, indicating that progression beyond this stage does not occur at any appreciable rate.