Fig. 1. Progressive definition of polar cell marker expression. A101/TM6 (A,B) and PZ80/Cy0 (C) ovarioles stained with anti-ß-galactosidase antibodies. Insets in A and C show magnification of indicated groups of 3 polar cell marker-expressing cells found in stage 2 to 4 egg chambers. B shows a group of 5 A101⁺ cells found in a stage 2 egg chamber.