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- Jansson, Mija, 1979-, et al.
(författare)
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Monitoring rate of inbreeding and loss of genetic variation in traditional Swedish dog breeds of conservation concern using pedigree data
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Increasing conservation genetic focus is directed towards domestic animal populations because: 1) domestic animals are of direct socio-economic importance to humans, and 2) strong selective breeding for a single or a few traits are considered to rapidly deplete the genetic variability of many domestic animal populations. International policy work within the Convention on Biological Diversity identifies strategies for minimizing genetic erosion of domesticated animals as one of the key biodiversity targets for 2010-2020. We investigated recent rate of inbreeding and loss of genetic variation in 12 traditional Swedish dog breeds, 10 of which have been identified as of conservation concern by the Swedish Board of Agriculture. We used studbook data provided by the Swedish Kennel Club with pedigrees dating back to the mid 20th century and comprising 5-10 generations with 350-60,000 individuals per pedigree. We assessed levels of inbreeding and loss of genetic variation measured in relation to the number of founding animals (founder alleles) among live animals at five points in time (1980, 1990, 2000, 2006, and 2012). We found average inbreeding coefficients among breeds to double over our period of monitoring, from an average of 0.03 over breeds in 1980 to 0.07 in 2012. This is in spite of the majority of breeds being large with pedigrees comprising thousands of individuals. The loss of genetic variation is extensive with an average of 70 percent loss of founder alleles over the study period, and the proportion of founder genome equivalents in relation to the number of founders is on average only 0.09. This is comparable to previously published rates of genetic variability loss in dog breeds, indicating that the explicit conservation goals for these traditional Swedish breeds is not yet reflected in conservation genetic status. One of the breeds is particularly threatened - the Gotland hound with less than 150 living individuals, but this breed also shows comparably larger retention of genetic variation.
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- Jansson, Mija, 1979-, et al.
(författare)
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Supportive release from a zoo population by cross-fostering can significantly increase genetic variation in the highly inbred wild Swedish wolf population
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The wild wolf population (Canis lupus) in Sweden is classified as Endangered and descends from only five individuals. The population is isolated and highly inbred; individuals are on average more related to each other than siblings. Inbreeding depression expressed as reduced litter size and a high frequency of spinal disorders have been reported. Management goals include reducing levels of inbreeding, and one suggestion to achieve this is through crossfostering release of pups from a zoo conservation breeding program into wild dens. We used pedigree data of the wild and zoo populations, respectively, to evaluate to what extent the zoo population can support the wild one with respect to increased genetic variation and reduction of inbreeding. The results show a potential to almost double genetic variation measured as founder alleles from 11.2 to 21.1, despite the fact that the two populations have three common founders. Potentially, the number of founder genome equivalents can be increased from present 1.8 to around 3.2. However, to achieve maximum genetic support, almost 50 percent of the wild population gene pool must consist of genes from the zoo population. Average kinship in the joint population of zoo and wild wolves is 0.15, thus release of zoo wolves cannot in itself be expected to reduce average inbreeding below the management target of 0.1. We conclude that releases from the zoo can support but not resolve the genetically precarious situation of the wild Swedish wolf population.
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- Kurland, Sara, et al.
(författare)
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Genomic dynamics of brown trout (Salmo trutta) populations released to a novel environment
- 2024
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Population translocations occur for a variety of reasons, from displacement due to climate change, to human-induced transfers. Such actions have adverse effects on genetic variation and understanding their microevolutionary consequences requires monitoring. Here, we return to an experimental release of brown trout (Salmo trutta) in order to monitor genomic effects of population translocations. In 1979, fish from each of two genetically and ecologically separate populations were released at one point in time to the same lake system. Whole-genome sequencing data is used to characterize diversity within and divergence between introduced fish from different source populations and fish inhabiting two lakes down-stream of the release sites, sampled 30 years later (c. 5 generations). Diversity and divergence among introduced populations and fish sampled in the wild c. 5 generations later suggest extensive hybridization. Introduced fish are unequally represented in the lakes down-stream of the release sites, with fish from one population mainly contributing to the lake closest to the release site, and the fish from the other dominating the lake further downstream. We also identify genomic regions putatively under directional selection in the new lake system, where genes from one of the introduced populations, regulating metabolism, appear advantageous. Our results demonstrate that genetic effects of population translocations e.g., establishment, hybridization, and adaptation can be rapid after release into novel environments – even for a species with relatively small local effective population sizes and a large, complex genome. This is an important contribution to understanding the microevolutionary effects population translocations have on intraspecific diversity.
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- Palmé, Anna, et al.
(författare)
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Genetic monitoring reveals two sympatric brown trout populations in a small mountain lake
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- It is contentious to what extent sympatric speciation represents a general and taxonomically widespread phenomenon. Documenting the occurrence of multiple, genetically distinct populations within areas lacking barriers to gene flow can increase our understanding of this type of speciation, because such populations are expected to represent the first steps of sympatric speciation. We analyzed the genetic relationships among over 4000 brown trout (Salmo trutta) collected during 19 sampling years from a series of small mountain lakes in northern Scandinavia. Our results clearly indicate the presence of two sympatric populations within these lakes. The populations are characterized by a high degree of genetic divergence coupled with a lack of apparent phenotypic dichotomy. The differentiation pattern appears stable over the two decades monitored, and the exchange of individuals between the two populations appears small. The existence of sympatric populations characterized by substantial genetic divergence may be a much more common phenomenon than anticipated, but difficult to detect in situations where morphological or ecological differentiation is missing. Larger samples than typically collected in a single sampling effort may be needed for revealing situations of sympatry, and for reliable estimation of the number of populations.
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