| 1. |
- Wennerström, Lovisa, et al.
(författare)
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Genetic landscape with sharp discontinuities shaped by complex demographic history in moose (Alces alces)
- 2016
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Ingår i: Journal of Mammalogy. - : Oxford University Press (OUP). - 0022-2372 .- 1545-1542. ; 97:1, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- The moose (Alces alces) is the most intensely managed game species in Fennoscandia; approximately one-third of the population, ca. 160,000 animals, is harvested annually. Despite the species' biological and socioeconomic importance, there are knowledge gaps with respect to its intraspecific diversity and genetic structure. Recent studies of moose in neighboring countries report 2 genetic groups in Finland, 3 in Norway with one of them suggested to be of ancient origin, and no indications of bottlenecks. To delineate the spatial genetic landscape of the Swedish moose, we used allozyme variability from over 20,000 georeferenced moose collected all over Sweden in combination with 12 microsatellites (n = 1,200) and mitochondrial DNA (mtDNA) sequences (n = 44). We combined individual-based and traditional statistical approaches with coalescence-based simulations. The results indicate a complex history with bottlenecks and recent expansions that is consistent with historical records. Swedish moose are separated into 2 major genetic groups, a northern and a southern one, where the southern group is further divided into 3 subgroups. The 2 main subpopulations are moderately differentiated (F-ST = 0.1; R-ST = 0.07) and separated by sharp genetic discontinuities occurring over a relatively narrow transition zone in central Sweden that coincides with a similar, previously reported transition zone in Norway. This differentiation is not reflected in mtDNA variation, where no significant divergence was observed. Together with the F-ST andR(ST) similarities, this suggests that the 2 major subpopulations in Sweden reflect divergence shaped after the postglacial recolonization of Scandinavia. Neighborhood size assessments indicate that gene flow is relatively restricted with an estimated average dispersal distance of 3.5-11.1 km, and spatial autocorrelograms suggest that genetic similarity decreases almost linearly over space resulting in continuous genetic clines within major subgroups. Management areas largely coincide with genetic clusters, simplifying the integration of genetic information into management.
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| 2. |
- Xenikoudakis, G., et al.
(författare)
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Consequences of a demographic bottleneck on genetic structure and variation in the Scandinavian brown bear
- 2015
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Ingår i: Molecular Ecology. - : John Wiley & Sons. - 0962-1083 .- 1365-294X. ; 24:13, s. 3441-3454
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Tidskriftsartikel (refereegranskat)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.
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