TY - JOUR A1 - Garcia, Tzintzuni I. A1 - Matos, Isa A1 - Shen, Yingjia A1 - Pabuwal, Vagmita A1 - Coelho, Maria Manuela A1 - Wakamatsu, Yuko A1 - Schartl, Manfred A1 - Walter, Ronald B. T1 - Novel Method for Analysis of Allele Specific Expression in Triploid Oryzias latipes Reveals Consistent Pattern of Allele Exclusion JF - PLOS ONE N2 - Assessing allele-specific gene expression (ASE) on a large scale continues to be a technically challenging problem. Certain biological phenomena, such as X chromosome inactivation and parental imprinting, affect ASE most drastically by completely shutting down the expression of a whole set of alleles. Other more subtle effects on ASE are likely to be much more complex and dependent on the genetic environment and are perhaps more important to understand since they may be responsible for a significant amount of biological diversity. Tools to assess ASE in a diploid biological system are becoming more reliable. Non-diploid systems are, however, not uncommon. In humans full or partial polyploid states are regularly found in both healthy (meiotic cells, polynucleated cell types) and diseased tissues (trisomies, non-disjunction events, cancerous tissues). In this work we have studied ASE in the medaka fish model system. We have developed a method for determining ASE in polyploid organisms from RNAseq data and we have implemented this method in a software tool set. As a biological model system we have used nuclear transplantation to experimentally produce artificial triploid medaka composed of three different haplomes. We measured ASE in RNA isolated from the livers of two adult, triploid medaka fish that showed a high degree of similarity. The majority of genes examined (82%) shared expression more or less evenly among the three alleles in both triploids. The rest of the genes (18%) displayed a wide range of ASE levels. Interestingly the majority of genes (78%) displayed generally consistent ASE levels in both triploid individuals. A large contingent of these genes had the same allele entirely suppressed in both triploids. When viewed in a chromosomal context, it is revealed that these genes are from large sections of 4 chromosomes and may be indicative of some broad scale suppression of gene expression. KW - RNA-SEQ data KW - copy-number alteration KW - squalius alburnoides KW - gene expression KW - medaka KW - variant detection KW - transplantation KW - genome KW - generation KW - evolution Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-116000 SN - 1932-6203 VL - 9 IS - 6 ER - TY - JOUR A1 - Biscotti, Maria Assunta A1 - Gerdol, Marco A1 - Canapa, Adriana A1 - Forconi, Mariko A1 - Olmo, Ettore A1 - Pallavicini, Alberto A1 - Barucca, Marco A1 - Schartl, Manfred T1 - The Lungfish Transcriptome: A Glimpse into Molecular Evolution Events at the Transition from Water to Land JF - Scientific Reports N2 - Lungfish and coelacanths are the only living sarcopterygian fish. The phylogenetic relationship of lungfish to the last common ancestor of tetrapods and their close morphological similarity to their fossil ancestors make this species uniquely interesting. However their genome size, the largest among vertebrates, is hampering the generation of a whole genome sequence. To provide a partial solution to the problem, a high-coverage lungfish reference transcriptome was generated and assembled. The present findings indicate that lungfish, not coelacanths, are the closest relatives to land-adapted vertebrates. Whereas protein-coding genes evolve at a very slow rate, possibly reflecting a “living fossil” status, transposable elements appear to be active and show high diversity, suggesting a role for them in the remarkable expansion of the lungfish genome. Analyses of single genes and gene families documented changes connected to the water to land transition and demonstrated the value of the lungfish reference transcriptome for comparative studies of vertebrate evolution. KW - lungfish KW - transcriptome KW - genome KW - sarcopterygian fish Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167753 VL - 6 IS - 21571 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 -