Breakpoint distribution in male-linked translocations in Anopheles stephensi Liston.

A series of translocations involving the male chromosome and chromosome 3 was analyzed in Anopheles stephensi. Using three genetic markers in 3R, namely sp, dp, and Bl, the recombination distance between the breakpoint and each of the three markers was assessed. On the basis of control recombination it was possible to assign the breakpoint to the chromosome relative to the three markers. It was shown that the majority of breakpoints were located in the vicinity of dp-Bl and translocations were identified that showed complete linkage with each of the markers. The results are compared with the published data on radiation-induced breakage and used to interpret the difficulties that have been experienced in producing a genetic sexing system in this species.