Fig. 5. Karyotypic analysis of RNAi treated individuals. (A) PCR with Y-specific oligonucleotides carried on medfly genomic DNA. From lane 1 to 10, PCR on single males developed from dsRNA-injected embryos; lanes 11 and 12, PCR on single wild-type females; lanes 13 and 14, PCR on single wild-type males. PCR on flies of mixed sexes and a negative control are shown, respectively, in lanes 15 and 16. The PCR amplification patterns in lanes 1,2,6 and 7 correspond to those of wild-type males, indicating that the analysed adults have an XY karyotype. By contrast, no bands are detected in lanes 3-5,8-10 indicating that these males lack a Y chromosome and therefore are XX sexually transformed males. (B) Positive PCR control with Cctra specific primers (Cctra164+ and Cctra481–) showing that medfly genomic DNA is present in all samples. Lane M (A,B) presents the molecular weight marker.