@article {38312, title = {Genome-Wide Survey of Natural Selection on Functional, Structural, and Network Properties of Polymorphic Sites in Saccharomyces Paradoxus}, journal = {Molecular Biology and EvolutionMol Biol EvolMolecular Biology and EvolutionMol Biol Evol}, volume = {28}, year = {2011}, type = {10.1093/molbev/msr085}, abstract = {Background. To characterize the genetic basis of phenotypic evolution, numerous studies have identified individual genes that have likely evolved under natural selection. However, phenotypic changes may represent the cumulative effect of similar evolutionary forces acting on functionally related groups of genes. Phylogenetic analyses of divergent yeast species have identified functional groups of genes that have evolved at significantly different rates, suggestive of differential selection on the functional properties. However, due to environmental heterogeneity over long evolutionary timescales, selection operating within a single lineage may be dramatically different, and it is not detectable via interspecific comparisons alone. Moreover, interspecific studies typically quantify selection on protein-coding regions using the Dn/Ds ratio, which cannot be extended easily to study selection on noncoding regions or synonymous sites. The population genetic-based analysis of selection operating within a single lineage ameliorates these limitations. Findings. We investigated selection on several properties associated with genes, promoters, or polymorphic sites, by analyzing the derived allele frequency spectrum of single nucleotide polymorphisms (SNPs) in 28 strains of Saccharomyces paradoxus. We found evidence for significant differential selection between many functionally relevant categories of SNPs, underscoring the utility of function-centric approaches for discovering signatures of natural selection. When comparable, our findings are largely consistent with previous studies based on interspecific comparisons, with one notable exception: our study finds that mutations from an ancient amino acid to a relatively new amino acid are selectively disfavored, whereas interspecific comparisons have found selection against ancient amino acids. Several of our findings have not been addressed through prior interspecific studies: we find that synonymous mutations from preferred to unpreferred codons are selected against and that synonymous SNPs in the linker regions of proteins are relatively less constrained than those within protein domains. Conclusions. We present the first global survey of selection acting on various functional properties in S. paradoxus. We found that selection pressures previously detected over long evolutionary timescales have also shaped the evolution of S. paradoxus. Importantly, we also make novel discoveries untenable via conventional interspecific analyses.}, keywords = {derived allele frequency, Evolution, natural selection, yeast}, isbn = {0737-4038, 1537-1719}, author = {Vishnoi, Anchal and Sethupathy, Praveen and Simola, Daniel and Plotkin, Joshua B. and Sridhar Hannenhalli} } @article {38379, title = {Microbial oceanography in a sea of opportunity}, journal = {NatureNature}, volume = {459}, year = {2009}, type = {10.1038/nature08056}, abstract = {Plankton use solar energy to drive the nutrient cycles that make the planet habitable for larger organisms. We can now explore the diversity and functions of plankton using genomics, revealing the gene repertoires associated with survival in the oceans. Such studies will help us to appreciate the sensitivity of ocean systems and of the ocean{\textquoteright}s response to climate change, improving the predictive power of climate models.}, keywords = {Astronomy, astrophysics, Biochemistry, Bioinformatics, Biology, biotechnology, cancer, cell cycle, cell signalling, climate change, Computational Biology, development, developmental biology, DNA, drug discovery, earth science, ecology, environmental science, Evolution, evolutionary biology, functional genomics, Genetics, Genomics, geophysics, immunology, interdisciplinary science, life, marine biology, materials science, medical research, medicine, metabolomics, molecular biology, molecular interactions, nanotechnology, Nature, neurobiology, neuroscience, palaeobiology, pharmacology, Physics, proteomics, quantum physics, RNA, Science, science news, science policy, signal transduction, structural biology, systems biology, transcriptomics}, isbn = {0028-0836}, author = {Bowler, Chris and Karl, David M. and Rita R. Colwell} } @article {38472, title = {Role of transposable elements in trypanosomatids}, journal = {Microbes and InfectionMicrobes and Infection}, volume = {10}, year = {2008}, type = {16/j.micinf.2008.02.009}, abstract = {Transposable elements constitute 2-5\% of the genome content in trypanosomatid parasites. Some of them are involved in critical cellular functions, such as the regulation of gene expression in Leishmania spp. In this review, we highlight the remarkable role extinct transposable elements can play as the source of potential new functions.}, keywords = {Cellular function, Domestication, Evolution, Gene expression, Leishmania, Regulation of mRNA stability, Retroposon, Transposable element, Trypanosoma}, isbn = {1286-4579}, author = {Bringaud, Frederic and Ghedin, Elodie and Najib M. El-Sayed and Papadopoulou, Barbara} } @article {38243, title = {Evolution of non-LTR retrotransposons in the trypanosomatid genomes: Leishmania major has lost the active elements}, journal = {Molecular and Biochemical ParasitologyMolecular and Biochemical Parasitology}, volume = {145}, year = {2006}, type = {16/j.molbiopara.2005.09.017}, abstract = {The ingi and L1Tc non-LTR retrotransposons - which constitute the ingi clade - are abundant in the genome of the trypanosomatid species Trypanosoma brucei and Trypanosoma cruzi, respectively. The corresponding retroelements, however, are not present in the genome of a closely related trypanosomatid, Leishmania major. To study the evolution of non-LTR retrotransposons in trypanosomatids, we have analyzed all ingi/L1Tc elements and highly degenerate ingi/L1Tc-related sequences identified in the recently completed T. brucei, T. cruzi and L. major genomes. The coding sequences of 242 degenerate ingi/L1Tc-related elements (DIREs) in all three genomes were reconstituted by removing the numerous frame shifts. Three independent phylogenetic analyses conducted on the conserved domains encoded by these elements show that all DIREs, including the 52 L. major DIREs, form a monophyletic group belonging to the ingi clade. This indicates that the trypanosomatid ancestor contained active mobile elements that have been retained in the Trypanosoma species, but were lost from L. major genome, where only remnants (DIRE) are detectable. All 242 DIREs analyzed group together according to their species origin with the exception of 11 T. cruzi DIREs which are close to the T. brucei ingi/DIRE families. Considering the absence of known horizontal transfer between the African T. brucei and the South-American T. cruzi, this suggests that this group of elements evolved at a lower rate when compared to the other trypanosomatid elements. Interestingly, the only nucleotide sequence conserved between ingi and L1Tc (the first 79 residues) is also present at the 5{\textquoteright}-extremity of all the full length DIREs and suggests a possible role for this conserved motif, as well as for DIREs.}, keywords = {Degenerate retroelement, Evolution, Ingi, L1Tc, Leishmania major, Non-LTR retrotransposon, Retroposon, Trypanosoma brucei, Trypanosoma cruzi}, isbn = {0166-6851}, author = {Bringaud, Frederic and Ghedin, Elodie and Blandin, Ga{\"e}lle and Bartholomeu, Daniella C. and Caler, Elisabet and Levin, Mariano J. and Baltz, Th{\'e}o and Najib M. El-Sayed} }