Fig. 1. Development of PGCs in urogenital ridge aggregates. Donor PGCs carrying a lacZ transgene were isolated from 11.5 dpc (A,B), 12.5 dpc (C) or 13.5 dpc (D) female genital ridges, and from 11.5 dpc (E,F), 12.5 dpc (G) or 13.5 dpc (H) male genital ridges, as indicated. The donor PGCs were aggregated with male (B-E) or female (A,F,G,H) 12.5 dpc recipient urogenital ridges (UGR) and cultured for 3-4 days. Donor PGCs are identified by a cyan perinuclear dot. Donor PGCs developing as oocytes (arrowheads) have condensed chromatin staining. Donor PGCs developing as prospermatogonia (arrows) have diffuse chromatin staining and prominent nucleoli. Scale bar: 10 µm.