TY  - JOUR
A1  - Franchini, Paolo
A1  - Jones, Julia C.
A1  - Xiong, Peiwen
A1  - Kneitz, Susanne
A1  - Gompert, Zachariah
A1  - Warren, Wesley C.
A1  - Walter, Ronald B.
A1  - Meyer, Axel
A1  - Schartl, Manfred
T1  - Long-term experimental hybridisation results in the evolution of a new sex chromosome in swordtail fish
JF  - Nature Communications
N2  - The remarkable diversity of sex determination mechanisms known in fish may be fuelled by exceptionally high rates of sex chromosome turnovers or transitions. However, the evolutionary causes and genomic mechanisms underlying this variation and instability are yet to be understood. Here we report on an over 30-year evolutionary experiment in which we tested the genomic consequences of hybridisation and selection between two Xiphophorus fish species with different sex chromosome systems. We find that introgression and imposing selection for pigmentation phenotypes results in the retention of an unexpectedly large maternally derived genomic region. During the hybridisation process, the sex-determining region of the X chromosome from one parental species was translocated to an autosome in the hybrids leading to the evolution of a new sex chromosome. Our results highlight the complexity of factors contributing to patterns observed in hybrid genomes, and we experimentally demonstrate that hybridisation can catalyze rapid evolution of a new sex chromosome.
KW  - evolutionary genetics
KW  - experimental evolution
KW  - genome evolution
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228396
VL  - 9
ER  - 
TY  - JOUR
A1  - Adolfi, Mateus C.
A1  - Du, Kang
A1  - Kneitz, Susanne
A1  - Cabau, Cédric
A1  - Zahm, Margot
A1  - Klopp, Christophe
A1  - Feron, Romain
A1  - Paixão, Rômulo V.
A1  - Varela, Eduardo S.
A1  - de Almeida, Fernanda L.
A1  - de Oliveira, Marcos A.
A1  - Nóbrega, Rafael H.
A1  - Lopez-Roques, Céline
A1  - Iampietro, Carole
A1  - Lluch, Jérôme
A1  - Kloas, Werner
A1  - Wuertz, Sven
A1  - Schaefer, Fabian
A1  - Stöck, Matthias
A1  - Guiguen, Yann
A1  - Schartl, Manfred
T1  - A duplicated copy of id2b is an unusual sex-determining candidate gene on the Y chromosome of arapaima (Arapaima gigas)
JF  - Scientific Reports
N2  - 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.
KW  - evolutionary genetics
KW  - genetic markers
KW  - genome
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-265672
VL  - 11
IS  - 1
ER  -