title: Sex-specific adaptation drives early sex chromosome evolution in Drosophila.
abstract: Most species' sex chromosomes are derived from ancient autosomes and show few signatures of their origins. We studied the sex chromosomes of Drosophila miranda, where a neo-Y chromosome originated only approximately 1 million years ago. Whole-genome and transcriptome analysis reveals massive degeneration of the neo-Y, that male-beneficial genes on the neo-Y are more likely to undergo accelerated protein evolution, and that neo-Y genes evolve biased expression toward male-specific tissues--the shrinking gene content of the neo-Y becomes masculinized. In contrast, although older X chromosomes show a paucity of genes expressed in male tissues, neo-X genes highly expressed in male-specific tissues undergo increased rates of protein evolution if haploid in males. Thus, the response to sex-specific selection can shift at different stages of X differentiation, resulting in masculinization or demasculinization of the X-chromosomal gene content.
authors: Department of Integrative Biology, University of California Berkeley, Berkeley, CA 94720, USA.
authors: Qi
authors: Q
authors: Zhou
authors: Doris
authors: D
authors: Bachtrog
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D000818:Animals; D004330:Drosophila / Q000235:genetics / Q000502:physiology*; D019143:Evolution, Molecular; D005260:Female; D005786:Gene Expression Regulation; D017344:Genes, Insect; D055106:Genome-Wide Association Study; D008297:Male; D009154:Mutation; D016366:Open Reading Frames; D012737:Sex Factors; D013737:Testis; D014960:X Chromosome / Q000235:genetics*; D014998:Y Chromosome / Q000235:genetics*