title: Consequences of a demographic bottleneck on genetic structure and variation in the Scandinavian brown bear.
abstract: The Scandinavian brown bear went through a major decline in population size approximately 100 years ago, due to intense hunting. After being protected, the population subsequently recovered and today numbers in the thousands. The genetic diversity in the contemporary population has been investigated in considerable detail, and it has been shown that the population consists of several subpopulations that display relatively high levels of genetic variation. However, previous studies have been unable to resolve the degree to which the demographic bottleneck impacted the contemporary genetic structure and diversity. In this study, we used mitochondrial and microsatellite DNA markers from pre- and postbottleneck Scandinavian brown bear samples to investigate the effect of the bottleneck. Simulation and multivariate analysis suggested the same genetic structure for the historical and modern samples, which are clustered into three subpopulations in southern, central and northern Scandinavia. However, the southern subpopulation appears to have gone through a marked change in allele frequencies. When comparing the mitochondrial DNA diversity in the whole population, we found a major decline in haplotype numbers across the bottleneck. However, the loss of autosomal genetic diversity was less pronounced, although a significant decline in allelic richness was observed in the southern subpopulation. Approximate Bayesian computations provided clear support for a decline in effective population size during the bottleneck, in both the southern and northern subpopulations. These results have implications for the future management of the Scandinavian brown bear because they indicate a recent loss in genetic diversity and also that the current genetic structure may have been caused by historical ecological processes rather than recent anthropogenic persecution.
authors.affiliation: Department of Bioinformatics and Genetics, Swedish Museum of Natural History, SE-10405, Stockholm, Sweden.|Department of Zoology, Stockholm University, SE-106 91, Stockholm, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Xenikoudakis
authors.affiliation: Department of Bioinformatics and Genetics, Swedish Museum of Natural History, SE-10405, Stockholm, Sweden.|Department of Zoology, Stockholm University, SE-106 91, Stockholm, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Ersmark
authors.affiliation: Department of Bioinformatics and Genetics, Swedish Museum of Natural History, SE-10405, Stockholm, Sweden.
authors.forename: J-L
authors.initials: JL
authors.lastname: Tison
authors.affiliation: Department of Fish and Wildlife Sciences, University of Idaho, 875 Perimeter Drive MS 1136, Moscow, ID, 83844, USA.
authors.forename: L
authors.initials: L
authors.lastname: Waits
authors.affiliation: Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, SE-90183, Umeå, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Kindberg
authors.affiliation: Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, NO-1432, Ås, Norway.|Norwegian Institute for Nature Research, PO Box 5685 Sluppen, NO-7485, Trondheim, Norway.
authors.forename: J E
authors.initials: JE
authors.lastname: Swenson
authors.affiliation: Department of Bioinformatics and Genetics, Swedish Museum of Natural History, SE-10405, Stockholm, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Dalén
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D004272:DNA, Mitochondrial / Q000235:genetics; D005787:Gene Frequency; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes; D018895:Microsatellite Repeats; D011156:Population Density; D011157:Population Dynamics; D012537:Scandinavian and Nordic Countries; D017422:Sequence Analysis, DNA; D001503:Ursidae / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial
keywords: Ursus arctos; bottleneck; decline; microsatellites; mtDNA