Meiotic drive in natural populations of Drosophila melanogaster .4: Instability at the Segregation Distorter locus

In a collection of flies from a natural population of Drosophila melanogaster, several second chromosomes have been isolated that contain, in the centromere region .of chromosome 11, a locus (named segregation-distorter and symbolized SO) that conditions, in heterozygous males, a highly abnormal segregation ratio in favor of the SD-bearing chromosome. Experiments bearing on the cytogenetic basis of the phenomenon of segregation-distortion and on the formal genetics of the SD locus have been reported by SANDLER, HIRAIZUMI, and SANDLER (1959). and by SANDLER and HIRAIZUMI ( 1959).