Project description:The naked mole-rat (NMR; Heterocephalus glaber) has recently gained considerable attention in the scientific community for its unique potential to unveil novel insights in the fields of medicine, biochemistry, and evolution. NMRs exhibit unique adaptations that include protracted fertility, cancer resistance, eusociality, and anoxia. This suite of adaptations is not found in other rodent species, suggesting that interrogating conserved and accelerated regions in the NMR genome will find regions of the NMR genome fundamental to their unique adaptations. However, the current NMR genome assembly has limits that make studying structural variations, heterozygosity, and non-coding adaptations challenging. We present a complete diploid naked-mole rat genome assembly by integrating long-read and 10X-linked read genome sequencing of a male NMR and its parents, and Hi-C sequencing in the NMR hypothalamus (N=2). Reads were identified as maternal, paternal or ambiguous (TrioCanu). We then polished genomes with Flye, Racon and Medaka. Assemblies were then scaffolded using the following tools in order: Scaff10X, Salsa2, 3d-DNA, Minimap2-alignment between assemblies, and the Juicebox Assembly Tools. We then subjected the assemblies to another round of polishing, including short-read polishing with Freebayes. We assembled the NMR mitochondrial genome with mitoVGP. Y chromosome contigs were identified by aligning male and female 10X linked reads to the paternal genome and finding male-biased contigs not present in the maternal genome. Contigs were assembled with publicly available male NMR Fibroblast Hi-C-seq data (SRR820318). Both assemblies have their sex chromosome haplotypes merged so that both assemblies have a high-quality X and Y chromosome. Finally, assemblies were evaluated with Quast, BUSCO, and Merqury, which all reported the base-pair quality and contiguity of both assemblies as high-quality. The assembly will next be annotated by Ensembl using public RNA-seq data from multiple tissues (SRP061363). Together, this assembly will provide a high-quality resource to the NMR and comparative genomics communities.

Project description:As a result of increasing thermal fluctuations and mean temperature values, organisms will experience conditions beyond their physiological limits. In situ adaptation to thermal regimes is mediated via directional selection and phenotypic plasticity. The latter involves physiological and morphological adjustments realized by underlying molecular mechanisms. Understanding species' adaptive capacities requires investigating these adjustive processes. Yet, acclimation through phenotypic plasticity remains largely unexplored, especially at the molecular level; For example, whether cold-adapted species inhabiting freshwater spring ecosystems have evolved adaptive mechanisms to cope with warming of freshwater habitats has, to our knowledge, never been investigated. This work reports a comprehensive proteomics study of the stenotopic species Crunoecia irrorata (Curtis, 1834) (Trichoptera: Lepistomatidae) acclimated to 10, 15 and 20 °C for 168 h. A liquid chromatography tandem mass spectrometry (LC-MS/MS)-based shotgun proteomics approach identified molecular mechanisms underlying acclimation. We constructed a homology-based database by combining genomic and transcriptomic data from related species and quantified 1356 proteins, of which 186 were differentially expressed between temperature treatments. Through functional annotation, we identified candidate proteins facilitating, among others, trehalose accumulation, tracheal system alteration, and heat shock protein regulation, then discuss concomitant ecophysiological implications. These results provide new insights into the mechanisms of adaptive responses to warming of species inhabiting freshwater ecosystems sensitive to climate change. Further, identified candidate proteins will aid in developing targeted experiments to understand their compensatory physiology. To our knowledge, this is the first study utilizing this approach to investigate the nature of phenotypic plasticity of aquatic macroinvertebrates.

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Trichoptera

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