Wolf population genetics in Europe: a systematic review, meta-analysis and suggestions for conservation and management (original) (raw)
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CHALLENGES IN EUROPEAN WOLF POPULATION MANAGEMENT
After centuries of intense persecution, wolves (Canis lupus) were regarded as being practically extinct in Europe. Today the wolf is granted the highest protection status in many EU countries and wolf populations are growing at an annual rate of 30 – 35 %. As wolf territories were established in settled areas, fragmentation was an increasingly important problem in the conservation of wolves. The sparse and fragmented wolf populations may have interbred with feral dogs during the early 1970's causing introgression and resulting in a complex mixture of parental genes from both dogs and wolves. Genetic monitoring of wolves started in the 1990's and the quality of the reference data constructed for populations analysis solely relied upon the expertise of the sampling personnel. As the wolves were being exterminated in Europe one century earlier, less efforts were put on separating hybrids from pure wolves due to the lack of experience and education. As the recovery of the wolf population had higher priority than wolf conservation, this led to large scale introgression resulting in a huge variety of wolves' phenotypes within limited areas. When genetic methods developed, more effort was put on conservation issues. This, in turn, has led into several interesting studies. Ettorio Randi et al found extensive introgression (87 %) in the Italian wolf population [3]. According to his research team, hybridization happened during the early phases of population re‐expansion in Italy. Zhenxin Fan et al came to the conclusion that 25 % of the European wolf population carries traces of dog introgression [4]. Large scale introgression has most likely polluted the reference populations in different countries making it impossible to separate pure wolves from wolves with dog genes. This, in turn, has led into a situation, where genetically pure wolves do not meet the morphological requirements defined when systematics as the science for identifying organisms was created. In order to turn wolf conservation back on track I present problems found in population analysis with SNP and microsatellites, and encourage the scientific community to use genetic markers and methods connected to phenotypic traits in order to verify the results of traditional population analysis. This paper focuses on the Agouti Signalling Protein (ASIP) that controls the localized expression of red and black pigment in the domestic dog through interaction with other genes [1].
PloS one, 2017
The survival of isolated small populations is threatened by both demographic and genetic factors. Large carnivores declined for centuries in most of Europe due to habitat changes, overhunting of their natural prey and direct persecution. However, the current rewilding trends are driving many carnivore populations to expand again, possibly reverting the erosion of their genetic diversity. In this study we reassessed the extent and origin of the genetic variation of the Italian wolf population, which is expanding after centuries of decline and isolation. We genotyped wolves from Italy and other nine populations at four mtDNA regions (control-region, ATP6, COIII and ND4) and 39 autosomal microsatellites. Results of phylogenetic analyses and assignment procedures confirmed in the Italian wolves a second private mtDNA haplotype, which belongs to a haplogroup distributed mostly in southern Europe. Coalescent analyses showed that the unique mtDNA haplotypes in the Italian wolves likely ori...
Living on the edge: reconstructing the genetic history of the Finnish wolf population
BMC Evolutionary Biology, 2014
Background: Many western European carnivore populations became almost or completely eradicated during the last~200 years, but are now recovering. Extirpation of wolves started in Finland in the 19th century, and for more than 150 years the population size of wolves has remained small. To investigate historical patterns of genetic variation, we extracted DNA from 114 wolf samples collected in zoological museums over the last~150 years. Fifteen microsatellite loci were used to look at genotypic variation in this historical sample. Additionally, we amplified a 430 bp sequence of mtDNA control region from the same samples. Contemporary wolf samples (N = 298) obtained after the population recovery in the mid-1990s, were used as a reference. Results: Our analyses of mtDNA revealed reduced variation in the mtDNA control region through the loss of historical haplotypes observed prior to wolf declines. Heterozygosity at autosomal microsatellite loci did not decrease significantly. However, almost 20% of microsatellite alleles were unique to wolves collected before the 1960s. The genetic composition of the population changed gradually with the largest changes occurring prior to 1920. Half of the oldest historical samples formed a distinguishable genetic cluster not detected in the modern-day Finnish or Russian samples, and might therefore represent northern genetic variation lost from today's gene pool. Point estimates of N e were small (13.2 and 20.5) suggesting population fragmentation. Evidence of a genetic population bottleneck was also detected. Conclusions: Our genetic analyses confirm changes in the genetic composition of the Finnish wolf population through time, despite the geographic interconnectivity to a much larger population in Russia. Our results emphasize the need for restoration of the historical connectivity between the present wolf populations to secure long-term viability. This might be challenging, however, because the management policies between Western and Eastern Europe often differ greatly. Additionally, wolf conservation is still a rather controversial issue, and anthropogenic pressure towards wolves remains strong.
PLoS ONE, 2014
Despite continuous historical distribution of the grey wolf (Canis lupus) throughout Eurasia, the species displays considerable morphological differentiation that resulted in delimitation of a number of subspecies. However, these morphological discontinuities are not always consistent with patterns of genetic differentiation. Here we assess genetic distinctiveness of grey wolves from the Caucasus (a region at the border between Europe and West Asia) that have been classified as a distinct subspecies C. l. cubanensis. We analysed their genetic variability based on mtDNA control region, microsatellite loci and genome-wide SNP genotypes (obtained for a subset of the samples), and found similar or higher levels of genetic diversity at all these types of loci as compared with other Eurasian populations. Although we found no evidence for a recent genetic bottleneck, genome-wide linkage disequilibrium patterns suggest a long-term demographic decline in the Caucasian population -a trend consistent with other Eurasian populations. Caucasian wolves share mtDNA haplotypes with both Eastern European and West Asian wolves, suggesting past or ongoing gene flow. Microsatellite data also suggest gene flow between the Caucasus and Eastern Europe. We found evidence for moderate admixture between the Caucasian wolves and domestic dogs, at a level comparable with other Eurasian populations. Taken together, our results show that Caucasian wolves are not genetically isolated from other Eurasian populations, share with them the same demographic trends, and are affected by similar conservation problems.
Background: Many western European carnivore populations became almost or completely eradicated during the last~200 years, but are now recovering. Extirpation of wolves started in Finland in the 19th century, and for more than 150 years the population size of wolves has remained small. To investigate historical patterns of genetic variation, we extracted DNA from 114 wolf samples collected in zoological museums over the last~150 years. Fifteen microsatellite loci were used to look at genotypic variation in this historical sample. Additionally, we amplified a 430 bp sequence of mtDNA control region from the same samples. Contemporary wolf samples (N = 298) obtained after the population recovery in the mid-1990s, were used as a reference. Results: Our analyses of mtDNA revealed reduced variation in the mtDNA control region through the loss of historical haplotypes observed prior to wolf declines. Heterozygosity at autosomal microsatellite loci did not decrease significantly. However, almost 20% of microsatellite alleles were unique to wolves collected before the 1960s. The genetic composition of the population changed gradually with the largest changes occurring prior to 1920. Half of the oldest historical samples formed a distinguishable genetic cluster not detected in the modern-day Finnish or Russian samples, and might therefore represent northern genetic variation lost from today's gene pool. Point estimates of N e were small (13.2 and 20.5) suggesting population fragmentation. Evidence of a genetic population bottleneck was also detected. Conclusions: Our genetic analyses confirm changes in the genetic composition of the Finnish wolf population through time, despite the geographic interconnectivity to a much larger population in Russia. Our results emphasize the need for restoration of the historical connectivity between the present wolf populations to secure long-term viability. This might be challenging, however, because the management policies between Western and Eastern Europe often differ greatly. Additionally, wolf conservation is still a rather controversial issue, and anthropogenic pressure towards wolves remains strong.
Scientific Reports, 2022
Intra-and inter-specific gene flow are natural evolutionary processes. However, human-induced hybridization is a global conservation concern across taxa, and the development of discriminant genetic markers to differentiate among gene flow processes is essential. Wolves (Canis lupus) are affected by hybridization, particularly in southern Europe, where ongoing recolonization of historic ranges is augmenting gene flow among divergent populations. Our aim was to provide diagnostic canid markers focused on the long-divergent Iberian, Italian and Dinaric wolf populations, based on existing genomic resources. We used 158 canid samples to select a panel of highly informative single nucleotide polymorphisms (SNPs) to (i) distinguish wolves in the three regions from domestic dogs (C. l. familiaris) and golden jackals (C. aureus), and (ii) identify their first two hybrid generations. The resulting 192 SNPs correctly identified the five canid groups, all simulated first-generation (F1) hybrids (0.482 ≤ Q i ≤ 0.512 between their respective parental groups) and all first backcross (BC1) individuals (0.723 ≤ Q i ≤ 0.827 to parental groups). An assay design and test with invasive and non-invasive canid samples performed successfully for 178 SNPs. By separating natural population admixture from interspecific hybridization, our reduced panel can help advance evolutionary research, monitoring, and timely conservation management. During the past centuries, long-term isolation and demographic declines in southern European peninsular populations of wolves (Canis lupus) caused considerable genetic drift that is now apparent in their genome-wide profiles 1-5. However, the ongoing spatial and demographic recovery of most European wolf populations, mainly due to legal protection and increased prey and habitat availability 6,7 , has prompted a gradual process of natural contact with dispersal and gene flow among discrete populations 8-10 .
Mammal Review, 2015
1. Following protection measures implemented since the 1970s, large carnivores are currently increasing in number and returning to areas from which they were absent for decades or even centuries. Monitoring programmes for these species rely extensively on non-invasive sampling and genotyping. However, attempts to connect results of such studies at larger spatial or temporal scales often suffer from the incompatibility of genetic markers implemented by researchers in different laboratories. This is particularly critical for long-distance dispersers, revealing the need for harmonized monitoring schemes that would enable the understanding of gene flow and dispersal dynamics. 2. Based on a review of genetic studies on grey wolves Canis lupus from Europe, we provide an overview of the genetic markers currently in use, and identify opportunities and hurdles for studies based on continent-scale datasets. 3. Our results highlight an urgent need for harmonization of methods to enable transnational research based on data that have already been collected, and to allow these data to be linked to material collected in the future. We suggest timely standardization of newly developed genotyping approaches, and propose that action is directed towards the establishment of shared single nucleotide polymorphism panels, next-generation sequencing of microsatellites, a common reference sample collection and an online database for data exchange. 4. Enhanced cooperation among genetic researchers dealing with large carnivores in consortia would facilitate streamlining of methods, their faster and wider adoption, and production of results at the large spatial scales that ultimately matter for the conservation of these charismatic species.
Genetic assessment of the Iberian wolf Canis lupus signatus captive breeding program
Conservation Genetics, 2006
Monitoring the loss of genetic diversity in wild populations after a bottleneck event is a priority in conservation and management plans. Here, we used diverse molecular markers to search for signatures of demographic bottlenecks in two wolf populations; an isolated population from the Iberian Peninsula and a non-isolated population from European Russia. Autosomal, mtDNA and Y-chromosomal diversity and the effective population size (N e ) were significantly lower in the Iberian population. Neutrality tests using mtDNA sequences, such as R 2, Fu and Li's F*, Tajima's D and Fu's F s , were positively significant in the Iberian population, suggesting a population decline, but were not significant for the Russian population, likely due to its larger effective population size. However, three tests using autosomal data confirmed the occurrence of the genetic bottleneck in both populations. The M-ratio test was the only one providing significant results for both populations. Given the lack of consistency among the different tests, we recommend using multiple approaches to investigate possible past bottlenecks. The small effective population size (about 50) in the Iberian Peninsula compared to the presumed extant population size could indicate that the bottleneck was more powerful than initially suspected or an overestimation of the current population. The risks associated with small effective population sizes suggest that the genetic change in this population should be closely monitored in the future. On the other hand, the relatively small effective population size for Russian wolves (a few hundred individuals) could indicate some fragmentation, contrary to what is commonly assumed.
Scientific Reports
Local extinction and recolonization events can shape genetic structure of subdivided animal populations. The gray wolf (Canis lupus) was extirpated from most of Europe, but recently recolonized big part of its historical range. An exceptionally dynamic expansion of wolf population is observed in the western part of the Great European Plain. Nonetheless, genetic consequences of this process have not yet been fully understood. We aimed to assess genetic diversity of this recently established wolf population in Western Poland (WPL), determine its origin and provide novel data regarding the population genetic structure of the grey wolf in Central Europe. We utilized both spatially explicit and non-explicit Bayesian clustering approaches, as well as a model-independent, multivariate method DAPC, to infer genetic structure in large dataset (881 identified individuals) of wolf microsatellite genotypes. To put the patterns observed in studied population into a broader biogeographic context ...