a sex-ratio meiotic drive system in drosophila simulans. i an autosomal suppressor性别比例在果蝇simulans减数分裂驱动系统。.pdfVIP

PLoS BIOLOGY A sex-ratio Meiotic Drive System in Drosophila simulans. I: An Autosomal Suppressor 1,2* 3¤ 1 1 1 Yun Tao , John P. Masly , Luciana Araripe , Yeyan Ke , Daniel L. Hartl 1 Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America, 2 Department of Biology, Emory University, Atlanta, Georgia, United States of America, 3 Department of Biology, University of Rochester, Rochester, New York, United States of America Sex ratio distortion (sex-ratio for short) has been reported in numerous species such as Drosophila, where distortion can readily be detected in experimental crosses, but the molecular mechanisms remain elusive. Here we characterize an autosomal sex-ratio suppressor from D. simulans that we designate as not much yang (nmy, polytene chromosome position 87F3). Nmy suppresses an X-linked sex-ratio distorter, contains a pair of near-perfect inverted repeats of 345 bp, and evidently originated through retrotransposition from the distorter itself. The suppression is likely mediated by sequence homology between the suppressor and distorter. The strength of sex-ratio is greatly enhanced by lower temperature. This temperature sensitivity was used to assign the sex-ratio etiology to the maturation process of the Y- bearing sperm, a hypothesis corroborated by both light microscope observations and ultrastructural studies. It has long been suggested that an X-linked sex-ratio distorter can evolve by exploiting loopholes in the meiotic machinery for its own transmission advantage, which may be offset by other changes in the genome that control the selfish distorter. Data obtained in this study hel