Fig. 1. Stwl is required for GSC maintenance. (A-C) Ovaries from heterozygous control animals (A) were dissected 10 days post-eclosion. Germ cells were labeled with the germ cell marker anti-Vasa (green), a fusome marker (anti-Hts, red) and the nuclear dye Hoechst (blue). Ovaries from stwl^Z1/stwl⁹⁵ mutant animals were dissected at 4 days (B) and 10 days (C) post-eclosion. (D-G) GSC clones were induced by heat-shock in adult animals and identified by the absence of nuclear GFP. (D) Clones induced in control wild-type genotype. Arrow points to the GSC. (E,F) The presence of clonally-related mutant germ cell clusters at 7 days post-heat-shock (outlined) indicated that each germ cell cluster was derived from a mutant stem cell. The stem cell region of this germarium, however, contained only wild-type stem cells (arrows). (G) Graph showing the frequency of negatively-marked stem cell clones from a wild-type FRT chromosome (blue) or two stwl-null chromosomes (yellow, pink) over a 2-week period.