Dataset Information

Global patterns of sequence evolution in Drosophila.

ABSTRACT: BACKGROUND: Sequencing of the genomes of several Drosophila allows for the first precise analyses of how global sequence patterns change among multiple, closely related animal species. A basic question is whether there are characteristic features that differentiate chromosomes within a species or between different species. RESULTS: We explored the euchromatin of the chromosomes of seven Drosophila species to establish their global patterns of DNA sequence diversity. Between species, differences in the types and amounts of simple sequence repeats were found. Within each species, the autosomes have almost identical oligonucleotide profiles. However, X chromosomes and autosomes have, in all species, a qualitatively different composition. The X chromosomes are less complex than the autosomes, containing both a higher amount of simple DNA sequences and, in several cases, chromosome-specific repetitive sequences. Moreover, we show that the right arm of the X chromosome of Drosophila pseudoobscura, which evolved from an autosome 10 - 18 millions of years ago, has a composition which is identical to that of the original, left arm of the X chromosome. CONCLUSION: The consistent differences among species, differences among X chromosomes and autosomes and the convergent evolution of X and neo-X chromosomes demonstrate that strong forces are acting on drosophilid genomes to generate peculiar chromosomal landscapes. We discuss the relationships of the patterns observed with differential recombination and mutation rates and with the process of dosage compensation.

SUBMITTER: Gallach M

PROVIDER: S-EPMC2180185 | biostudies-literature | 2007

REPOSITORIES: biostudies-literature

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Global patterns of sequence evolution in Drosophila.

Gallach Miguel M Arnau Vicente V Marín Ignacio I

BMC genomics 20071109

<h4>Background</h4>Sequencing of the genomes of several Drosophila allows for the first precise analyses of how global sequence patterns change among multiple, closely related animal species. A basic question is whether there are characteristic features that differentiate chromosomes within a species or between different species.<h4>Results</h4>We explored the euchromatin of the chromosomes of seven Drosophila species to establish their global patterns of DNA sequence diversity. Between species, ...[more]

PMID: 17996078

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Project description:Thermoacidophilic methane-oxidizing Verrucomicrobia of the candidate genus Methylacidiphilum represent a bacterial taxon adapted to highly acidic (pH 1-4) and moderate temperature (∼65°C) methane-containing geothermal environments. Their apparent ubiquity in acidic terrestrial volcanic areas makes them ideal model organisms to study prokaryotic biogeography. Three Methylacidiphilum species isolated from distantly-separated geothermal regions in Russia, New Zealand, and Italy were previously described. We have explored the intra-taxon phylogenetic patterns of these organisms based on comparative genome analyses and phenotypic comparisons with six new Verrucomicrobia methanotroph isolates from other globally-separated acidic geothermal locations. Comparison of rRNA and particulate methane monooxygenase (pmoCAB) operon sequences indicates a close phylogenetic relationship among the new isolates as well as with the previously characterized strains. All share similar cell morphology including the presence of extensive intracellular inclusion bodies and lack of intracellular membrane systems, which are typical for proteobacterial methanotrophs. However, genome sequence comparisons and concatenated MLST-based phylogenetic analyses separate the new isolates into three distinct species-level groups. Three recently processed isolates from the Azores (each from geographically-separate hot springs within the region) and a single isolate from Iceland are highly similar, sharing more than 88% in silico genome homology with each other as well as with the previous isolate, Methylacidiphilum fumariolicum strain SolV, from Italy. These appear to constitute a distinct European/Atlantic clade. However, two of the new isolates - one from the Yellowstone National Park (United States) and another from The Philippines - constitute separate and novel Methylacidiphilum species. There is no clear correlation between fatty acid profiles and geographic distance between origins, or any phylogenetic relationship. Serological analysis using antiserum raised against M. kamchatkense strain Kam1 revealed large differences in the degree of cross-reactivity with no correlation with other factors. However, the genetic distance between the strains does correlate to the distance between their geographic origins and suggests a global biogeographic pattern shaped by an isolation-by-distance mechanism. These results further confirm terrestrial geothermal springs as isolated islands featuring allopatric prokaryotic speciation.

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Global patterns of sequence evolution in Drosophila.

Publications

Global patterns of sequence evolution in Drosophila.

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