GENETIC AND CYTOLOGICAL MAPPING OF A Y-2 TRANSLOCATION IN THE MEDITERRANEAN FRUIT-FLY CERATITIS-CAPITATA

In this paper we analyze genetically and cytologically a Y - chromosom e 2 translocation with several markers, some of which are potentially useful for large scale sex separation. The breakpoint of this Y-2 tran slocation is located at region 6B on the trichogene polytene chromosom e map. It was found that, in strains carrying this TY-2, only 40% of t he fertilized eggs survived to the adult stage, 26% of them dying as e mbryos, 27% as larvae, and 7% as pupae. Early lethality is explained b y the nonviability of adjacent-1 products of meiosis containing a dele tion of section 1A-6B. The reciprocal segregation products, carrying t his chromosome segment in triplicate, survive until late stages. By an alyzing the phenotype of these individuals we conclude that all marker s used in this study are located outside the triplicated region and th at the male determining factor is not included in the piece of the Y c hromosome translocated to chromosome 2. The male recombination frequen cies of several genes located on chromosome 2 relative to the breakpoi nt of translocation T5038 have also been studied here.