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The duplication of entire genomes has long been recognized as having great potential for evolutionary novelties, but the mechanisms underlying their resolution through gene loss are poorly understood. Here we show that in the unicellular eukaryote Paramecium tetraurelia, a ciliate, most of the nearly 40,000 genes arose through at least three successive(More)
Unraveling the evolutionary forces responsible for variations of neutral substitution patterns among taxa or along genomes is a major issue in the identification of functional sequence features. Mammalian genomes show large-scale regional variations of GC-content (the isochores), but the substitution processes at the origin of this structure are poorly(More)
We have sequenced to high levels of accuracy 714-kb and 233-kb regions of the mouse and bovine X-inactivation centers (Xic), respectively, centered on the Xist gene. This has provided the basis for a fully annotated comparative analysis of the mouse Xic with the 2.3-Mb orthologous region in human and has allowed a three-way species comparison of the core(More)
Unraveling the evolutionary forces responsible for variations of neutral substitution patterns among taxa or along genomes is a major issue for detecting selection within sequences. Mammalian genomes show large-scale regional variations of GC-content (the isochores), but the substitution processes at the origin of this structure are poorly understood. We(More)
In an attempt to understand the origin of CpG islands (CGIs) in mammalian genomes, we have studied their location and structure according to the expression pattern of genes and to the G + C content of isochores in which they are embedded. We show that CGIs located over the transcription start site (named start CGIs) are very different structurally from the(More)
B ASE composition is spatially structured in mamma-isochores may simply reflect variable mutation processes among genomic regions, consistent with the neutral lian genomes. From sodium chloride centrifuga-tion experiments, Bernardi et al. (1985) defined three model. Such variation in mutational biases has never been demonstrated. Alternatively, isochores(More)
The analysis of evolutionary rates is a popular approach to characterizing the effect of natural selection at the molecular level. Sequences contributing to species adaptation are expected to evolve faster than nonfunctional sequences because favourable mutations have a higher fixation probability than neutral ones. Such an accelerated rate of evolution(More)
Insertions of parasitic DNA within coding sequences are usually deleterious and are generally counter-selected during evolution. Thanks to nuclear dimorphism, ciliates provide unique models to study the fate of such insertions. Their germline genome undergoes extensive rearrangements during development of a new somatic macronucleus from the germline(More)
Integr8 is a new web portal for exploring the biology of organisms with completely deciphered genomes. For over 190 species, Integr8 provides access to general information, recent publications, and a detailed statistical overview of the genome and proteome of the organism. The preparation of this analysis is supported through Genome Reviews, a new database(More)
  • J Romiguier, P Gayral, M Ballenghien, A Bernard, V Cahais, A Chenuil +15 others
  • 2014
Genetic diversity is the amount of variation observed between DNA sequences from distinct individuals of a given species. This pivotal concept of population genetics has implications for species health, domestication, management and conservation. Levels of genetic diversity seem to vary greatly in natural populations and species, but the determinants of(More)