Autoria: ADOLFI, M. C.; DU, K.; KNEITZ, S.; CABAU, C.; ZAHM, M.; KLOPP, C.; FERON, R.; PAIXÃO, R. V.; VARELA, E. S.; O'SULLIVAN, F. L. A.; OLIVEIRA, M. A. de; NÓBREGA, R. H.; LOPEZ-ROQUES, C.; IAMPIETRO, C.; LLUCH, J.; KLOAS, W.; WUERTZ, S.; SCHAEFER, F.; STÖCK, M.; GUIGUEN, Y.; SCHARTL, M.

Resumo: 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 B 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.

Ano de publicação: 2021

Tipo de publicação: Artigo de periódico

Unidade: Embrapa Pesca e Aquicultura

Palavras-chave: Arapaima gigas, Chromosomes, Cromossoma, Cytogenetics, Fish, Peixe, Pirarucu, Sex chromosomes, Sex determination