Zp-R,the identification and mapping of a homeotic mutation associated with ectopic eyes in D.simulans. R.P. Lachtermacher , C.E. Vanario-Alonso , E. Abdelhay. IBCCF, UFRJ, Rio de Janeiro, Rio de Janeiro, Brasil.

   The Antennapedia (Antp) and eyeless (ey) are master control genes with the power to start developmental programs. The genetic analysis of a spontaneous D.simulans mutant, showing an atennae to leg transformation, and occasional ectopic eye formation was carried out. X chromosome substitution and segregation tests using a D.simulans balancer,resulted in the establishment of a mutant isoline,Zp-R. This isoline showed 89% of flies with Antp-like phenotype and 6.6% with ectopic eyes in addition. These phenotypes suggest that the mutation is dominant. Genetic mapping was performed using D.simulans genetic markers 3L jv'se'. The frequency of recombination values were 35.9 and after converting this result to genetic map distance,Zp-R was localized between sections 70 and 71(3L). A comparative cytological analysis of 3L chromosome, between Zp-R and wt D.simulans showed a sequence of approximately five unidentified bands inserted between sections 70C and 71C. Another difference was a fragment insertion containing sections 70B until 70F into section 67B. A molecular analysis by Southern blot using a D.melanogaster eyeless probe at low stringency, showed significative differences in hybridization patterns between Zp-R and D.simulans wild type adult genomic DNA samples. These results suggest that this mutation is affecting a gene containing a homeobox which is probably involved in antennae/eye developmental programs.