AnSD(Segregation Distribution) –MR(Male Recombination) chromosome isolated from a natural population ofDrosophila melanogaster

Abstract

SUMMARYA second chromosome line ofDrosophila melanogaster(S-90), isolated from a northern California natural population, is able to induce (1) an increased frequency of X-chromosome visible mutations, (2) male recombination activity subject to reciprocal cross suppression, and (3) strong meiotic drive from heterozygous males. Based upon several lines of evidence (including the response to suppressor chromosomes of both systems) we conclude thatS-90contains bothSD(Segregation Distortion) andMR(PorI) chromosome activity. The two systems appear to behave independently and simultaneously, and a small centromeric region of theS-90chromosome appears to contain the major genetic elements of both systems.