Low Spontaneous Mutation Rate and Pleistocene Radiation of Pea Aphids.

Accurate estimates of divergence times are essential to understand the evolutionary history of species. It allows linking evolutionary histories of the diverging lineages with past geological, climatic, and other changes in environment and shed light on the processes involved in speciation. The pea aphid radiation includes multiple host races adapted to different legume host plants.

Intrinsic pre-zygotic reproductive isolation of distantly related pea aphid host races.

Human activities may weaken or destroy reproductive isolation between young taxa, leading to their fusion with consequences for population and community ecology. Pea aphid host races are adapted to different legume taxa, providing a degree of pre-mating isolation mediated by habitat choice. Yet, all races can feed and reproduce on the broad bean (), a major crop which represents a 'universal host plant', which can promote hybridization between races.

Repeated unidirectional introgression of nuclear and mitochondrial DNA between four congeneric Tanganyikan cichlids.

With an increasing number of reported cases of hybridization and introgression, interspecific gene flow between animals has recently become a widely accepted and broadly studied phenomenon. In this study, we examine patterns of hybridization and introgression in Ophthalmotilapia spp., a genus of cichlid fish from Lake Tanganyika, using mitochondrial and nuclear DNA from all four species in the genus and including specimens from over 800 km of shoreline.

When environmental changes do not cause geographic separation of fauna: differential responses of Baikalian invertebrates.

Background: While the impact of climate fluctuations on the demographic histories of species caused by changes in habitat availability is well studied, populations of species from systems without geographic isolation have received comparatively little attention. Using CO1 mitochondrial sequences, we analysed phylogeographic patterns and demographic histories of populations of five species (four gastropod and one amphipod species) co-occurring in the southwestern shore of Lake Baikal, an area where environmental oscillations have not resulted in geographical isolation of habitats.

Results: Species with stronger habitat preferences (gastropods B.