Fig. 4. zpg is required for survival of bam `stem-cell tumors'. Ovaries from flies of the indicated genotypes were stained with anti-Vasa (green) and the mAb 1B1 antibody (red). zpg bam /+ bam ovaries showed the bam phenotype with many `stem cell-like' germ cells and no egg chambers (A). zpg bam / zpg+ flies had the zpg phenotype with few germ cells at the tip of the ovariole (B). zpg and bam or bgcn double mutant ovaries (C,D) had a similar phenotype to that of zpg, with only a few germ cells located at the tip of the ovary. However, the number of germ cells at the tip was higher than in zpg single mutants (compare panel B with panels C,D). Scale bar in D: 50 µm for A-D.