title: Genetic and phenoptypic differentiation of zebra mussel populations colonizing Spanish river basins.
abstract: Zebra mussel populations in Ebro and Mijares Rivers (northern Spain) were analyzed to study the mechanisms by which this aquatic species deals with pollution. Variability analyses of mitochondrial cytochrome oxidase I gene and of one nuclear microsatellite were performed for ten populations from the Ebro River and one from the Mijares River. Comparison of these results with those from five additional European populations indicated that the Spanish populations constitute a homogeneous gene pool. Transcriptome analyses of gill samples from a subset of the Spanish populations showed changes on expression levels that correlated with variations in general fitness and loads of heavy metals. The less polluted upstream Ebro populations showed overexpression of mitochondrial and cell proliferation-related genes compared to the more polluted, downstream Ebro populations. Our data indicate that heavy metals were the main factors explaining these transcriptomic patterns, and that zebra mussel is resilient to pollutants (like mercury and organochlorine compounds) proved to be extremely toxic to vertebrates. We propose that zebra mussel populations sharing a common gene pool may acclimate to different levels and forms of pollution through modulations in their transcriptomic profile, although direct selection on genes showing differential expression patterns cannot be ruled out.
authors.affiliation: Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research, IDAEA-CSIC, Jordi Girona 18, 08034 Barcelona, Spain.
authors.forename: Anna
authors.initials: A
authors.lastname: Navarro
authors.forename: Javier
authors.initials: J
authors.lastname: Sánchez-Fontenla
authors.forename: David
authors.initials: D
authors.lastname: Cordero
authors.forename: Melisa
authors.initials: M
authors.lastname: Faria
authors.forename: Juan B
authors.initials: JB
authors.lastname: Peña
authors.forename: Carlos
authors.initials: C
authors.lastname: Saavedra
authors.forename: Mercedes
authors.initials: M
authors.lastname: Blázquez
authors.forename: Olga
authors.initials: O
authors.lastname: Ruíz
authors.forename: Rocío
authors.initials: R
authors.lastname: Ureña
authors.forename: Amparo
authors.initials: A
authors.lastname: Torreblanca
authors.forename: Carlos
authors.initials: C
authors.lastname: Barata
authors.forename: Benjamin
authors.initials: B
authors.lastname: Piña
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects*; D000818:Animals; D049875:Dreissena / Q000502:physiology*; D017753:Ecosystem; D059647:Gene-Environment Interaction; D005838:Genotype; D010641:Phenotype; D045483:Rivers; D013030:Spain; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical