title: Accelerated pseudogenization on the neo-X chromosome in Drosophila miranda.
abstract: Y chromosomes often degenerate via the accumulation of pseudogenes and transposable elements. By contrast, little is known about X-chromosome degeneration. Here we compare the pseudogenization process between genes on the neo-sex chromosomes in Drosophila miranda and their autosomal orthologues in closely related species. The pseudogenization rate on the neo-X is much lower than the rate on the neo-Y, but appears to be higher than the rate on the orthologous autosome in D. pseudoobscura. Genes under less functional constraint and/or genes with male-biased expression tend to become pseudogenes on the neo-X, indicating the accumulation of slightly deleterious mutations and the feminization of the neo-X. We also find a weak trend that the genes with female-benefit/male-detriment effects identified in D. melanogaster are pseudogenized on the neo-X, implying the masculinization of the neo-X. These observations suggest that both X and Y chromosomes can degenerate due to a complex suite of evolutionary forces.
authors.affiliation: Center for Information Biology, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan.|Department of Genetics, SOKENDAI, 1111 Yata, Mishima, Shizuoka 411-8540, Japan.|Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minamiosawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Nozawa
authors.affiliation: Center for Information Biology, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Onizuka
authors.affiliation: Center for Information Biology, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan.
authors.forename: Mai
authors.initials: M
authors.lastname: Fujimi
authors.affiliation: Center for Information Biology, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan.|Department of Genetics, SOKENDAI, 1111 Yata, Mishima, Shizuoka 411-8540, Japan.
authors.forename: Kazuho
authors.initials: K
authors.lastname: Ikeo
authors.affiliation: Center for Information Biology, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan.|King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center, Biological and Environmental Science and Engineering, 4700 KAUST, Thuwal 23955-6900; Kingdom of Saudi Arabia.
authors.forename: Takashi
authors.initials: T
authors.lastname: Gojobori
mesh_terms: D000818:Animals; D004330:Drosophila / Q000235:genetics*; D019143:Evolution, Molecular; D005260:Female; D005262:Feminization; D005786:Gene Expression Regulation; D050172:Genes, X-Linked; D007621:Karyotyping; D008297:Male; D010802:Phylogeny; D011544:Pseudogenes; D014960:X Chromosome / Q000235:genetics*; D014998:Y Chromosome / Q000235:genetics