Connectivity and population subdivision at the fringe of a large brown bear (Ursus arctos) population in North Western Europe

Kopatz, Alexander; Eiken, Hans Geir; Hagen, Snorre B.; Ruokonen, Minna; Esparza‐Salas, Rodrigo; Schregel, Julia; Kojola, Ilpo; Smith, Martin A.; Wartiainen, Ingvild; Aspholm, Paul Eric; Wikan, Steinar; Rykov, Alexander M.; Макарова, О. Л.; Polikarpova, Natalia; Tirronen, Konstantin; Danilov, Pjotr; Aspi, Jouni

doi:10.1007/s10592-012-0317-2

Cited by 72 publications

(53 citation statements)

References 84 publications

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“…Previously, we have detected bi-directional migration rates of about 30% between bears in Eastern Finland and bears further east in Arkhangelsk, Russia [28]. Another study applying autosomal microsatellites to a restricted number of samples suggested that Finnish bears are divided into a northern and a southern subpopulation [30].…”

Section: Introductionmentioning

confidence: 85%

Admixture and Gene Flow from Russia in the Recovering Northern European Brown Bear (Ursus arctos)

et al. 2014

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Large carnivores were persecuted to near extinction during the last centuries, but have now recovered in some countries. It has been proposed earlier that the recovery of the Northern European brown bear is supported by migration from Russia. We tested this hypothesis by obtaining for the first time continuous sampling of the whole Finnish bear population, which is located centrally between the Russian and Scandinavian bear populations. The Finnish population is assumed to experience high gene flow from Russian Karelia. If so, no or a low degree of genetic differentiation between Finnish and Russian bears could be expected. We have genotyped bears extensively from all over Finland using 12 validated microsatellite markers and compared their genetic composition to bears from Russian Karelia, Sweden, and Norway. Our fine masked investigation identified two overlapping genetic clusters structured by isolation-by-distance in Finland (pairwise FST = 0.025). One cluster included Russian bears, and migration analyses showed a high number of migrants from Russia into Finland, providing evidence of eastern gene flow as an important driver during recovery. In comparison, both clusters excluded bears from Sweden and Norway, and we found no migrants from Finland in either country, indicating that eastern gene flow was probably not important for the population recovery in Scandinavia. Our analyses on different spatial scales suggest a continuous bear population in Finland and Russian Karelia, separated from Scandinavia.

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Section: Introductionmentioning

confidence: 85%

Admixture and Gene Flow from Russia in the Recovering Northern European Brown Bear (Ursus arctos)

et al. 2014

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“…Polar bears exhibit low levels of population differentiation at biparentally inherited and mitochondrial markers throughout their range (Paetkau et al 1999;Cronin and MacNeil 2012;Miller et al 2012;Campagna et al 2013). Brown bears, in contrast, show considerable phylogeographic structuring at mitochondrial markers (Davison et al 2011;Edwards et al 2011;Hirata et al 2013;Keis et al 2013), and population structuring can also be discerned at biparentally inherited microsatellites (Paetkau et al 1997;Tammeleht et al 2010;Kopatz et al 2012). Most mtDNA clades are confined to certain geographical regions and are not shared between continents, although one brown bear clade is widespread throughout Eurasia and extends into North America (Korsten et al 2009;Davison et al 2011).…”

Section: Introductionmentioning

confidence: 99%

“…Surprisingly, all range-wide phylogeographic studies on brown bears have so far relied on mtDNA. Studies of autosomal markers were regionally restricted to either North America or Eurasia (Paetkau et al 1997;Tammeleht et al 2010;Kopatz et al 2012;Cahill et al 2013), and no phylogeographic study of Y chromosome markers in bears exists. However, analysis of male-specific markers is crucial to understand bear evolution in the light of their well-documented male-biased dispersal (McLellan and Hovey 2001;Zedrosser et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Brown and Polar Bear Y Chromosomes Reveal Extensive Male-Biased Gene Flow within Brother Lineages

Bidon

Janke

Fain

et al. 2014

Molecular Biology and Evolution

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Brown and polar bears have become prominent examples in phylogeography, but previous phylogeographic studies relied largely on maternally inherited mitochondrial DNA (mtDNA) or were geographically restricted. The male-specific Y chromosome, a natural counterpart to mtDNA, has remained underexplored. Although this paternally inherited chromosome is indispensable for comprehensive analyses of phylogeographic patterns, technical difficulties and low variability have hampered its application in most mammals. We developed 13 novel Y-chromosomal sequence and microsatellite markers from the polar bear genome and screened these in a broad geographic sample of 130 brown and polar bears. We also analyzed a 390-kb-long Y-chromosomal scaffold using sequencing data from published male ursine genomes. Y chromosome evidence support the emerging understanding that brown and polar bears started to diverge no later than the Middle Pleistocene. Contrary to mtDNA patterns, we found 1) brown and polar bears to be reciprocally monophyletic sister (or rather brother) lineages, without signals of introgression, 2) male-biased gene flow across continents and on phylogeographic time scales, and 3) male dispersal that links the Alaskan ABC islands population to mainland brown bears. Due to female philopatry, mtDNA provides a highly structured estimate of population differentiation, while male-biased gene flow is a homogenizing force for nuclear genetic variation. Our findings highlight the importance of analyzing both maternally and paternally inherited loci for a comprehensive view of phylogeographic history, and that mtDNA-based phylogeographic studies of many mammals should be reevaluated. Recent advances in sequencing technology render the analysis of Y-chromosomal variation feasible, even in nonmodel organisms.

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“…Our previous data on autosomal STRs showed extensive gene flow between Finnish and Russian brown bears (Kopatz et al . , ), but low gene flow farther westwards (Schregel et al . ; Kopatz et al .…”

Section: Discussionmentioning

confidence: 99%

“…We used DNA samples of verified male individuals, analysed and stored in the course of regional and national monitoring programmes conducted in Sweden and Norway, as well as during previous studies conducted in Finland (Kopatz et al . , ; Schregel et al . ; Hagen et al .…”

Section: Methodsmentioning

confidence: 99%

Y chromosome haplotype distribution of brown bears (Ursus arctos) in Northern Europe provides insight into population history and recovery

Schregel

Eiken

Grøndahl³

et al. 2015

Molecular Ecology

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High-resolution, male-inherited Y-chromosomal markers are a useful tool for population genetic analyses of wildlife species, but to date have only been applied in this context to relatively few species besides humans. Using nine Y-chromosomal STRs and three Y-chromosomal single nucleotide polymorphism markers (Y-SNPs), we studied whether male gene flow was important for the recent recovery of the brown bear (Ursus arctos) in Northern Europe, where the species declined dramatically in numbers and geographical distribution during the last centuries but is expanding now. We found 36 haplotypes in 443 male extant brown bears from Sweden, Norway, Finland and northwestern Russia. In 14 individuals from southern Norway from 1780 to 1920, we found two Y chromosome haplotypes present in the extant population as well as four Y chromosome haplotypes not present among the modern samples. Our results suggested major differences in genetic connectivity, diversity and structure between the eastern and the western populations in Northern Europe. In the west, our results indicated that the recovered population originated from only four male lineages, displaying pronounced spatial structuring suggestive of large-scale population size increase under limited male gene flow within the western subpopulation. In the east, we found a contrasting pattern, with high haplotype diversity and admixture. This first population genetic analysis of male brown bears shows conclusively that male gene flow was not the main force of population recovery.

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Connectivity and population subdivision at the fringe of a large brown bear (Ursus arctos) population in North Western Europe

Cited by 72 publications

References 84 publications

Admixture and Gene Flow from Russia in the Recovering Northern European Brown Bear (Ursus arctos)

Admixture and Gene Flow from Russia in the Recovering Northern European Brown Bear (Ursus arctos)

Brown and Polar Bear Y Chromosomes Reveal Extensive Male-Biased Gene Flow within Brother Lineages

Y chromosome haplotype distribution of brown bears (Ursus arctos) in Northern Europe provides insight into population history and recovery

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