@article{KuhlGuiguenHoehneetal.2021,
  author    = {Kuhl, Heiner and Guiguen, Yann and H{\"o}hne, Christin and Kreuz, Eva and Du, Kang and Klopp, Christophe and Lopez-Roques,, C{\´e}line and Yebra-Pimentel, Elena Santidrian and Ciorpac, Mitica and Gessner, J{\"o}rn and Holostenco, Daniela and Kleiner, Wibke and Kohlmann, Klaus and Lamatsch, Dunja K. and Prokopov, Dmitry and Bestin, Anastasia and Bonpunt, Emmanuel and Debeuf, Bastien and Haffray, Pierrick and Morvezen, Romain and Patrice, Pierre and Suciu, Radu and Dirks, Ron and Wuertz, Sven and Kloas, Werner and Schartl, Manfred and St{\"o}ck, Matthias},
  title     = {A 180 Myr-old female-specific genome region in sturgeon reveals the oldest known vertebrate sex determining system with undifferentiated sex chromosomes},
  series = {Philosophical Transactions of the Royal Society B},
  volume    = {376},
  journal   = {Philosophical Transactions of the Royal Society B},
  doi       = {10.1098/rstb.2020.0089},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-363050},
  year      = {2021},
  abstract  = {Several hypotheses explain the prevalence of undifferentiated sex chromosomes in poikilothermic vertebrates. Turnovers change the master sex determination gene, the sex chromosome or the sex determination system (e.g. XY to WZ). Jumping master genes stay main triggers but translocate to other chromosomes. Occasional recombination (e.g. in sex-reversed females) prevents sex chromosome degeneration. Recent research has uncovered conserved heteromorphic or even homomorphic sex chromosomes in several clades of non-avian and non-mammalian vertebrates. Sex determination in sturgeons (Acipenseridae) has been a long-standing basic biological question, linked to economical demands by the caviar-producing aquaculture. Here, we report the discovery of a sex-specific sequence from sterlet (Acipenser ruthenus). Using chromosome-scale assemblies and pool-sequencing, we first identified an approximately 16 kb female-specific region. We developed a PCR-genotyping test, yielding female-specific products in six species, spanning the entire phylogeny with the most divergent extant lineages (A. sturio, A. oxyrinchus versus A. ruthenus, Huso huso), stemming from an ancient tetraploidization. Similar results were obtained in two octoploid species (A. gueldenstaedtii, A. baerii). Conservation of a female-specific sequence for a long period, representing 180 Myr of sturgeon evolution, and across at least one polyploidization event, raises many interesting biological questions. We discuss a conserved undifferentiated sex chromosome system with a ZZ/ZW-mode of sex determination and potential alternatives. This article is part of the theme issue 'Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part I)'.},
  language  = {en}
}
@article{DuWuertzAdolfietal.2019,
  author    = {Du, Kang and Wuertz, Sven and Adolfi, Mateus and Kneitz, Susanne and St{\"o}ck, Matthias and Oliveira, Marcos and N{\´o}brega, Rafael and Ormanns, Jenny and Kloas, Werner and Feron, Romain and Klopp, Christophe and Parrinello, Hugues and Journot, Laurent and He, Shunping and Postlethwait, John and Meyer, Axel and Guiguen, Yann and Schartl, Manfred},
  title     = {The genome of the arapaima (Arapaima gigas) provides insights into gigantism, fast growth and chromosomal sex determination system},
  series = {Scientific Reports},
  volume    = {9},
  journal   = {Scientific Reports},
  doi       = {10.1038/s41598-019-41457-x},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201333},
  pages     = {5293},
  year      = {2019},
  abstract  = {We have sequenced the genome of the largest freshwater fish species of the world, the arapaima. Analysis of gene family dynamics and signatures of positive selection identified genes involved in the specific adaptations and unique features of this iconic species, in particular it's large size and fast growth. Genome sequences from both sexes combined with RAD-tag analyses from other males and females led to the isolation of male-specific scaffolds and supports an XY sex determination system in arapaima. Whole transcriptome sequencing showed that the product of the gland-like secretory organ on the head surface of males and females may not only provide nutritional fluid for sex-unbiased parental care, but that the organ itself has a more specific function in males, which engage more in parental care.},
  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}
}