@article {9730, title = {Not Frozen in the Ice: Large and Dynamic Rearrangements in the Mitochondrial Genomes of the Antarctic Fish}, journal = {Genome Biology and Evolution}, volume = {13}, year = {2021}, month = {2021 Mar 01}, abstract = {

The vertebrate mitochondrial genomes generally present a typical gene order. Exceptions are uncommon and important to study the genetic mechanisms of gene order rearrangements and their consequences on phylogenetic output and mitochondrial function. Antarctic notothenioid fish carry some peculiar rearrangements of the mitochondrial gene order. In this first systematic study of 28 species, we analyzed known and undescribed mitochondrial genome rearrangements for a total of eight different gene orders within the notothenioid fish. Our reconstructions suggest that transpositions, duplications, and inversion of multiple genes are the most likely mechanisms of rearrangement in notothenioid mitochondrial genomes. In Trematominae, we documented an extremely rare inversion of a large genomic segment of 5,300 bp that partially affected the gene compositional bias but not the phylogenetic output. The genomic region delimited by nad5 and trnF, close to the area of the Control Region, was identified as the hot spot of variation in Antarctic fish mitochondrial genomes. Analyzing the sequence of several intergenic spacers and mapping the arrangements on a newly generated phylogeny showed that the entire history of the Antarctic notothenioids is characterized by multiple, relatively rapid, events of disruption of the gene order. We hypothesized that a pre-existing genomic flexibility of the ancestor of the Antarctic notothenioids may have generated a precondition for gene order rearrangement, and the pressure of purifying selection could have worked for a rapid restoration of the mitochondrial functionality and compactness after each event of rearrangement.

}, keywords = {Animals, Antarctic Regions, Evolution, Molecular, Fishes, Freezing, Gene Order, Gene Rearrangement, Genes, Mitochondrial, Genome, Mitochondrial, Genomics, Ice, Models, Genetic, Phylogeny, Vertebrates}, issn = {1759-6653}, doi = {10.1093/gbe/evab017}, url = {https://doi.org/10.1093/gbe/evab017}, author = {Papetti, Chiara and Babbucci, Massimiliano and Dettai, Agn{\`e}s and Basso, Andrea and Lucassen, Magnus and Harms, Lars and C{\'e}line Bonillo and Heindler, Franz Maximilian and Patarnello, Tomaso and Negrisolo, Enrico} } @article {3394, title = {The Jumonji gene family in Crassostrea gigas suggests evolutionary conservation of Jmj-C histone demethylases orthologues in the oyster gametogenesis and development.}, journal = {Gene}, volume = {538}, year = {2014}, month = {2014 Mar 15}, pages = {164-75}, abstract = {

Jumonji (Jmj) proteins are histone demethylases, which control the identity of stem cells. Jmj genes were characterized from plants to mammals where they have been implicated in the epigenetic regulation of development. Despite the Pacific oyster Crassostrea gigas representing one of the most important aquaculture resources worldwide, the molecular mechanisms governing the embryogenesis and reproduction of this lophotrochozoan species remain poorly understood. However, annotations in the C. gigas EST library suggested the presence of putative Jumonji genes, raising the question of the conservation of this family of histone demethylases in the oyster. Using Primer walking, 5{\textquoteright}-RACE PCR and in silico analyses, we characterized nine Jumonji orthologues in the oyster, called Cg-Jmj, bearing conserved domains critical for putative histone demethylase activity. Phylogenic analyses revealed that oyster Jumonji cluster into two distinct groups: {\textquoteright}single-domain Jmj{\textquoteright} and {\textquoteright}multi-domain Jmj{\textquoteright}, and define 8 subgroups corresponding to each cognate orthologues in metazoans. RT-qPCR investigations showed specific regulations of Cg-Jmj mRNAs during the early development and along the reproduction cycle. Furthermore, in situ and in toto hybridizations indicate that oyster Jumonji genes are transcribed mostly within the gonad in adult oysters whereas they display a ubiquitous expression during embryonic and larval development. Our study demonstrates the presence of nine Jumonji orthologues in the oyster C. gigas. Their domain conservation and their expression profile suggest an implication during reproduction and development, questioning about the epigenetic regulation by histone methylation in lophotrochozoans.

}, keywords = {Animals, Base Sequence, Conserved Sequence, Crassostrea, Evolution, Molecular, Gametogenesis, Gene Expression Regulation, Developmental, Jumonji Domain-Containing Histone Demethylases, Molecular Sequence Data, Multigene Family, RNA, Messenger}, issn = {1879-0038}, doi = {10.1016/j.gene.2013.12.016}, author = {Alexandre Fellous and Pascal Favrel and Guo, Ximing and Guillaume Rivi{\`e}re} } @article {3486, title = {New Sicydiinae phylogeny (Teleostei: Gobioidei) inferred from mitochondrial and nuclear genes: insights on systematics and ancestral areas.}, journal = {Mol Phylogenet Evol}, volume = {70}, year = {2014}, month = {2014 Jan}, pages = {260-71}, abstract = {

The Sicydiinae subfamily (Teleostei: Gobioidei) is the biggest contributor to the diversity of fish communities in river systems of tropical islands. These species are found in the Indo-Pacific area, the Caribbean region and West Africa. They spawn in freshwater, their planktotrophic larvae drift downstream to the sea where they develop, before returning to the rivers to grow and reproduce. Hence, they are called amphidromous. Their phylogeny has been explored using a total of 3545 sites from 5 molecular markers (mitochondrial DNA: 16S rDNA, cytochrome oxidase I, cytochrome b; nuclear DNA: rhodopsin gene and a nuclear marker specially developed for this study, the interferon regulatory factor 2 binding protein 1-IRF2PB1). Sequences were obtained for 59 Sicydiinae specimens of 9 known genera. The Bayesian and maximum likelihood analyses support the monophyly of the subfamily as well as the monophylyof all genera except Sicydium, which is paraphyletic. Five major clades were identified within this subfamily. One clade contained the genus Stiphodon. Another clade contained Sicyopterus, Sicydium and Parasicydium with Sicyopterus as sister genus of Sicydium. The non-monophyly of Sicydium subclade, because it includes the monotypic genus Parasicydium, challenged the validity of Parasicydium genus. Ancestral area reconstruction showed that the subfamily emerged in the Central West Pacific region implying that previous hypotheses proposing a dispersal route for Sicydiinae into the Atlantic Ocean are unsupported by the present analysis. Our results suggest that the hypotheses for the dispersal route of the genus Sicydium should be reconsidered.

}, keywords = {Animals, Bayes Theorem, Cell Nucleus, Cytochromes b, DNA, Mitochondrial, DNA, Ribosomal, Electron Transport Complex IV, Evolution, Molecular, Female, Mitochondria, Perciformes, Phylogeny, Sequence Analysis, DNA}, issn = {1095-9513}, doi = {10.1016/j.ympev.2013.09.026}, author = {Taillebois, Laura and Castelin, Magalie and Clara Lord and Chabarria, Ryan and Dettai, Agn{\`e}s and Philippe Keith} }