caa a22 4500 530216868 CHVBK 20200120040831.0 cr unu---uuuuu 181027e20181005xx s 000 0 eng 10.1186/s13059-018-1548-4 doi (SERVAL)BIB_3979DBC2E6AC 30290841 pmid 000446444000002 isiid Evolutionary and developmental dynamics of sex-biased gene expression in common frogs with proto-Y chromosomes [Elektronische Daten] [W.J. Ma, P. Veltsos, R. Sermier, D.J. Parker, N. Perrin] The patterns of gene expression on highly differentiated sex chromosomes differ drastically from those on autosomes, due to sex-specific patterns of selection and inheritance. As a result, X chromosomes are often enriched in female-biased genes (feminization) and Z chromosomes in male-biased genes (masculinization). However, it is not known how quickly sexualization of gene expression and transcriptional degeneration evolve after sex-chromosome formation. Furthermore, little is known about how sex-biased gene expression varies throughout development. We sample a population of common frogs (Rana temporaria) with limited sex-chromosome differentiation (proto-sex chromosome), leaky genetic sex determination evidenced by the occurrence of XX males, and delayed gonadal development, meaning that XY individuals may first develop ovaries before switching to testes. Using high-throughput RNA sequencing, we investigate the dynamics of gene expression throughout development, spanning from early embryo to froglet stages. Our results show that sex-biased expression affects different genes at different developmental stages and increases during development, reaching highest levels in XX female froglets. Additionally, sex-biased gene expression depends on phenotypic, rather than genotypic sex, with similar expression in XX and XY males; correlates with gene evolutionary rates; and is not localized to the proto-sex chromosome nor near the candidate sex-determining gene Dmrt1. The proto-sex chromosome of common frogs does not show evidence of sexualization of gene expression, nor evidence for a faster rate of evolution. This challenges the notion that sexually antagonistic genes play a central role in the initial stages of sex-chromosome evolution. Ma W.J. aut Veltsos P. aut Sermier R. aut Parker D.J. aut Perrin N. aut Genome biology 19/1(2018-10-05), 156 19:1<156 2018 19 1 article serval SERVAL 700 1- Ma W.J. aut SERVAL 700 1- Veltsos P. aut SERVAL 700 1- Sermier R. aut SERVAL 700 1- Parker D.J. aut SERVAL 700 1- Perrin N. aut SERVAL 773 0- Genome biology 19/1(2018-10-05), 156 19:1<156 2018 19 BK010053 XK010053 XK010000 SERVAL SERVAL SERVAL article