The evolutionary fate of recently duplicated retrogenes in mice.

Inferences about the evolutionary impact of gene duplications often rely on the analysis of their long-term outcome. The fate of the majority of them must, however, be decided shortly after duplication. Here we analysed the evolutionary pattern of 10 mouse genes very recently duplicated by retrotransposition, by sequencing the retroposed copy in five to 10 closely related mouse species. In all cases the retroposed copy experienced accelerated nonsynonymous evolution whereas the divergence pattern of the source copy appeared unaffected by the duplication, consistent with the neofunctionalization model. The analysis further revealed that most retrogenes, including pseudogenes, did not experience a period of relaxed neutral evolution, but have been submitted to purifying selection ever since their retroposition. We propose that these duplicates play a biochemical role but are not indispensable. Purifying selection prevents them from acquiring a negative role until they are lost or silenced. This period of unnecessary redundancy could in rare cases give the time for new functions to evolve.

Mouse biodiversity in the genomic era.

Comparative genomics has developed by comparison of distantly related genomes, for which the link between the reported evolutionary changes and species development/physiology/ecology is not obvious. It is argued that the mouse (genus Mus) is an optimal model for microevolutionary genomics in vertebrates. This is because the mouse genome sequence, physical and genetic map have been completed, because mouse genetics, morpho-anatomy, pathology, behavior and ecology are well-studied, and because the Mus genus is a diverse, well- documented taxon, allowing comparative studies at the level of individual, population, subspecies, and species. The potential of the interaction between mouse genome and mouse biodiversity is illustrated by recent studies of speciation in the house mouse Mus musculus, and studies about the evolution of isochores, the peculiar pattern of GC-content variation across mammalian genomes.

Qualitative and quantitative molecular detection of enteroviruses in water from bathing areas and from a sewage treatment plant.

Pathogenic enteric viruses can be introduced into the environment as a result of human activities. Enteroviruses are regularly detected in environmental waters or shellfish and can provoke potentially serious diseases. Some authors believe that enteroviruses could represent an interesting indicator of viral contamination in the environment. Since molecular approaches seem to be promising for the detection of these viruses, we developed a simple qualitative RT-PCR procedure for enteroviruses, together with a quantitative RT-PCR assay using RNA internal standard. After one-tube-RT-PCR, this standard and wild enterovirus RNA were detected by differential hybridization with specific probes and a fluorimetric reaction. The quantification of enteroviruses, conducted in a sewage treatment plant, showed a decreasing number of genomic copies from the entrance to the exit (from 3.8 x 10(5) to 5.4 x 10(4) RNA copies/mL) but indicated the presence of enterovirus RNA in the neighboring river (2.2 x 10(3) RNA copies/mL). In bathing areas, enterovirus RNA was detected in 16 out of 226 samples, with copies numbers ranging from 3.7 x 10(2) RNA copies/mL to 7 x 10(4) RNA copies/mL.