@article{FranchiniJonesXiongetal.2018, author = {Franchini, Paolo and Jones, Julia C. and Xiong, Peiwen and Kneitz, Susanne and Gompert, Zachariah and Warren, Wesley C. and Walter, Ronald B. and Meyer, Axel and Schartl, Manfred}, title = {Long-term experimental hybridisation results in the evolution of a new sex chromosome in swordtail fish}, series = {Nature Communications}, volume = {9}, journal = {Nature Communications}, doi = {10.1038/s41467-018-07648-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228396}, year = {2018}, abstract = {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.}, language = {en} } @article{KimAmoresKangetal.2019, author = {Kim, Bo-Mi and Amores, Angel and Kang, Seunghyun and Ahn, Do-Hwan and Kim, Jin-Hyoung and Kim, Il-Chan and Lee, Jun Hyuck and Lee, Sung Gu and Lee, Hyoungseok and Lee, Jungeun and Kim, Han-Woo and Desvignes, Thomas and Batzel, Peter and Sydes, Jason and Titus, Tom and Wilson, Catherine A. and Catchen, Julian M. and Warren, Wesley C. and Schartl, Manfred and Detrich, H. William III and Postlethwait, John H. and Park, Hyun}, title = {Antarctic blackfin icefish genome reveals adaptations to extreme environments}, series = {Nature Ecology \& Evolution}, volume = {3}, journal = {Nature Ecology \& Evolution}, doi = {10.1038/s41559-019-0812-7}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-325811}, pages = {469-478}, year = {2019}, abstract = {Icefishes (suborder Notothenioidei; family Channichthyidae) are the only vertebrates that lack functional haemoglobin genes and red blood cells. Here, we report a high-quality genome assembly and linkage map for the Antarctic blackfin icefish Chaenocephalus aceratus, highlighting evolved genomic features for its unique physiology. Phylogenomic analysis revealed that Antarctic fish of the teleost suborder Notothenioidei, including icefishes, diverged from the stickleback lineage about 77 million years ago and subsequently evolved cold-adapted phenotypes as the Southern Ocean cooled to sub-zero temperatures. Our results show that genes involved in protection from ice damage, including genes encoding antifreeze glycoprotein and zona pellucida proteins, are highly expanded in the icefish genome. Furthermore, genes that encode enzymes that help to control cellular redox state, including members of the sod3 and nqo1 gene families, are expanded, probably as evolutionary adaptations to the relatively high concentration of oxygen dissolved in cold Antarctic waters. In contrast, some crucial regulators of circadian homeostasis (cry and per genes) are absent from the icefish genome, suggesting compromised control of biological rhythms in the polar light environment. The availability of the icefish genome sequence will accelerate our understanding of adaptation to extreme Antarctic environments.}, language = {en} } @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} }