title: Genetic Variability and Structuring of Arctic Charr (Salvelinus alpinus) Populations in Northern Fennoscandia.
abstract: Variation in presumably neutral genetic markers can inform us about evolvability, historical effective population sizes and phylogeographic history of contemporary populations. We studied genetic variability in 15 microsatellite loci in six native landlocked Arctic charr (Salvelinus alpinus) populations in northern Fennoscandia, where this species is considered near threatened. We discovered that all populations were genetically highly (mean FST ≈ 0.26) differentiated and isolated from each other. Evidence was found for historical, but not for recent population size bottlenecks. Estimates of contemporary effective population size (Ne) ranged from seven to 228 and were significantly correlated with those of historical Ne but not with lake size. A census size (NC) was estimated to be approximately 300 individuals in a pond (0.14 ha), which exhibited the smallest Ne (i.e. Ne/NC = 0.02). Genetic variability in this pond and a connected lake is severely reduced, and both genetic and empirical estimates of migration rates indicate a lack of gene flow between them. Hence, albeit currently thriving, some northern Fennoscandian populations appear to be vulnerable to further loss of genetic variability and are likely to have limited capacity to adapt if selection pressures change.
authors.affiliation: Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, Helsinki, Finland.
authors.forename: Takahito
authors.initials: T
authors.lastname: Shikano
authors.affiliation: Kilpisjärvi Biological Station, University of Helsinki, Kilpisjärvi, Finland.
authors.forename: Antero
authors.initials: A
authors.lastname: Järvinen
authors.affiliation: Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, Helsinki, Finland.
authors.forename: Paula
authors.initials: P
authors.lastname: Marjamäki
authors.affiliation: Kilpisjärvi Biological Station, University of Helsinki, Kilpisjärvi, Finland; Department of Environmental Sciences, University of Helsinki, Helsinki, Finland.
authors.forename: Kimmo K
authors.initials: KK
authors.lastname: Kahilainen
authors.affiliation: Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, Helsinki, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Merilä
mesh_terms: D000483:Alleles; D025041:Animal Migration; D000818:Animals; D016000:Cluster Analysis; D056426:Genetic Loci; D014644:Genetic Variation; D005828:Genetics, Population; D018895:Microsatellite Repeats; D058974:Phylogeography; D011156:Population Density; D014337:Trout / Q000145:classification / Q000235:genetics*