A sex-ratio meiotic drive system in Drosophila simulans. II: an X-linked distorter.
The evolution of heteromorphic sex chromosomes creates a genetic condition favoring the invasion of sex-ratio meiotic drive elements, resulting in the biased transmission of one sex chromosome over the other, in violation of Mendel's first law. The molecular mechanisms of sex-ratio meiotic drive may therefore help us to understand the evolutionary forces shaping the meiotic behavior of the sex chromosomes. Here we characterize a sex-ratio distorter on the X chromosome (Dox) in Drosophila simulans by genetic and molecular means. Intriguingly, Dox has very limited coding capacity. It evolved from another X-linked gene, which also evolved de nova. Through retrotransposition, Dox also gave rise to an autosomal suppressor, not much yang (Nmy). An RNA interference mechanism seems to be involved in the suppression of the Dox distorter by the Nmy suppressor. Double mutant males of the genotype dox; nmy are normal for both sex-ratio and spermatogenesis. We postulate that recurrent bouts of sex-ratio meiotic drive and its subsequent suppression might underlie several common features observed in the heterogametic sex, including meiotic sex chromosome inactivation and achiasmy.
Tao
Yun
Y
Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America. ytao3@emory.edu
Araripe
Luciana
L
Kingan
Sarah B
SB
Ke
Yeyan
Y
Xiao
Hailian
H
Hartl
Daniel L
DL
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics; D019143:Evolution, Molecular; D005260:Female; D016153:Genes, Suppressor; D008297:Male; D008540:Meiosis; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D034622:RNA Interference; D012744:Sex Ratio; D014960:X Chromosome / Q000235:genetics*; D014998:Y Chromosome / Q000235:genetics
D029721:Drosophila Proteins