Adaptive alien genes are maintained amid a vanishing introgression footprint in a sea squirt.

Human transport of species across oceans disrupts natural dispersal barriers and facilitates hybridization between previously allopatric species. The recent introduction of the North Pacific sea squirt, , into the native range of the North Atlantic sea squirt, , is a good example of this outcome. Recent studies have revealed an adaptive introgression in a single chromosomal region from the introduced into the native species.

Marine transmissible cancer navigates urbanized waters, threatening spillover.

Inter-individual transmission of cancer cells represents a unique form of microparasites increasingly reported in marine bivalves. In this study, we sought to understand the ecology of the propagation of Bivalve Transmissible Neoplasia 2 (MtrBTN2), a transmissible cancer affecting four mussel species worldwide. We investigated the prevalence of MtrBTN2 in the mosaic hybrid zone of and along the French Atlantic coast, sampling contrasting natural and anthropogenic habitats.

Transcriptomics of mussel transmissible cancer MtrBTN2 suggests accumulation of multiple cancer traits and oncogenic pathways shared among bilaterians.

Transmissible cancer cell lines are rare biological entities giving rise to diseases at the crossroads of cancer and parasitic diseases. These malignant cells have acquired the amazing capacity to spread from host to host. They have been described only in dogs, Tasmanian devils and marine bivalves.

Anthropogenic Change and the Process of Speciation.

Anthropogenic impacts on the environment alter speciation processes by affecting both geographical contexts and selection patterns on a worldwide scale. Here we review evidence of these effects. We find that human activities often generate spatial isolation between populations and thereby promote genetic divergence but also frequently cause sudden secondary contact and hybridization between diverging lineages.