Fig. 1. shar-pei mutant clones result in outgrowths on head, thorax and halteres. Wild-type (left column) and mutant (right column) adult structures imaged by light and scanning electron microscopy (SEM). (A,B) Dorsal views of a normal sized fly (A) and a fly with a shrp mutant head (B). Both flies are genetic mosaics. We used the eyFLP transgene to induce recombination in most cells of the eye-antennal disc (Newsome et al., 2000). To increase the number of clone cells, a cell-lethal mutation on the homologous chromosome was used to eliminate homozygous twin clone cells (Newsome et al., 2000). In the normal sized fly, 80% of cells are white but otherwise wild type. In the mutant fly, white cells are also homozygous mutant for shrp. These mutant cells make up virtually the entire eye. The body is wild type and serves as a reference for comparison of head sizes, because mitotic recombination was specifically induced in the developing head by using eyFLP. The genotypes are (A) y w eyFLP; FRT82B/FRT82B cell lethal p[w⁺] and (B) y w eyFLP; FRT82B shrp¹/FRT82B cell lethal p[w⁺]. (C,D) SEM images of a wild-type fly and a fly with a shrp³ mutant head produced by eyFLP induced mitotic recombination as for (B). (E,F) Higher magnifications of C,D. The mutant tissue is severely overgrown and folds up. Ocelli (arrows), bristles and hairs differentiated normally. (G,H) Wild-type thorax and a thorax with shrp³ mutant clones. The clones result in overgrown tissue (arrow). (I,J) Wild-type haltere (I) and haltere with shrp³ mutant clones (J). The mutant haltere is much larger than normal.