Fig. 3. piy mutation behaves in a cell-autonomous manner. (A) Transplantation of wild-type zebrafish cells into wild-type recipient retinas. Wild-type donor cells (brown) form retinal columns. (B) Transplantation of wild-type cells into piy mutant recipient retinas. Although most of the recipient cells undergo apoptosis, wild-type donor cells (brown) survive and form retinal columns (arrowheads). (C) Transplantation of piy mutant cells into wild-type recipient retinas. Transplanted mutant cells fail to form retinal columns and instead remain as a very small cell mass (arrowhead). (D) Transplantation of piy mutant cells into wild-type recipient retinas. piy donor mutant cells (red) are TUNEL-positive (green, arrowheads) in the wild-type recipient retina.