@article{AdolfiDuKneitzetal.2021, author = {Adolfi, Mateus C. and Du, Kang and Kneitz, Susanne and Cabau, C{\´e}dric and Zahm, Margot and Klopp, Christophe and Feron, Romain and Paix{\~a}o, R{\^o}mulo V. and Varela, Eduardo S. and de Almeida, Fernanda L. and de Oliveira, Marcos A. and N{\´o}brega, Rafael H. and Lopez-Roques, C{\´e}line and Iampietro, Carole and Lluch, J{\´e}r{\^o}me and Kloas, Werner and Wuertz, Sven and Schaefer, Fabian and St{\"o}ck, Matthias and Guiguen, Yann and Schartl, Manfred}, title = {A duplicated copy of id2b is an unusual sex-determining candidate gene on the Y chromosome of arapaima (Arapaima gigas)}, series = {Scientific Reports}, volume = {11}, journal = {Scientific Reports}, number = {1}, doi = {10.1038/s41598-021-01066-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265672}, year = {2021}, abstract = {Arapaima gigas is one of the largest freshwater fish species of high ecological and economic importance. Overfishing and habitat destruction are severe threats to the remaining wild populations. By incorporating a chromosomal Hi-C contact map, we improved the arapaima genome assembly to chromosome-level, revealing an unexpected high degree of chromosome rearrangements during evolution of the bonytongues (Osteoglossiformes). Combining this new assembly with pool-sequencing of male and female genomes, we identified id2bbY, a duplicated copy of the inhibitor of DNA binding 2b (id2b) gene on the Y chromosome as candidate male sex-determining gene. A PCR-test for id2bbY was developed, demonstrating that this gene is a reliable male-specific marker for genotyping. Expression analyses showed that this gene is expressed in juvenile male gonads. Its paralog, id2ba, exhibits a male-biased expression in immature gonads. Transcriptome analyses and protein structure predictions confirm id2bbY as a prime candidate for the master sex-determiner. Acting through the TGF beta signaling pathway, id2bbY from arapaima would provide the first evidence for a link of this family of transcriptional regulators to sex determination. Our study broadens our current understanding about the evolution of sex determination genetic networks and provide a tool for improving arapaima aquaculture for commercial and conservation purposes.}, language = {en} } @article{AdolfiHerpinMartinezBengocheaetal.2021, author = {Adolfi, Mateus C. and Herpin, Amaury and Martinez-Bengochea, Anabel and Kneitz, Susanne and Regensburger, Martina and Grunwald, David J. and Schartl, Manfred}, title = {Crosstalk Between Retinoic Acid and Sex-Related Genes Controls Germ Cell Fate and Gametogenesis in Medaka}, series = {Frontiers in Cell and Developmental Biology}, volume = {8}, journal = {Frontiers in Cell and Developmental Biology}, issn = {2296-634X}, doi = {10.3389/fcell.2020.613497}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-222669}, year = {2021}, abstract = {Sex determination (SD) is a highly diverse and complex mechanism. In vertebrates, one of the first morphological differences between the sexes is the timing of initiation of the first meiosis, where its initiation occurs first in female and later in male. Thus, SD is intimately related to the responsiveness of the germ cells to undergo meiosis in a sex-specific manner. In some vertebrates, it has been reported that the timing for meiosis entry would be under control of retinoic acid (RA), through activation of Stra8. In this study, we used a fish model species for sex determination and lacking the stra8 gene, the Japanese medaka (Oryzias latipes), to investigate the connection between RA and the sex determination pathway. Exogenous RA treatments act as a stress factor inhibiting germ cell differentiation probably by activation of dmrt1a and amh. Disruption of the RA degrading enzyme gene cyp26a1 induced precocious meiosis and oogenesis in embryos/hatchlings of female and even some males. Transcriptome analyzes of cyp26a1-/-adult gonads revealed upregulation of genes related to germ cell differentiation and meiosis, in both ovaries and testes. Our findings show that germ cells respond to RA in a stra8 independent model species. The responsiveness to RA is conferred by sex-related genes, restricting its action to the sex differentiation period in both sexes.}, language = {en} }