Genetik der Wölfe: Hybridisierung, Introgression und Abstammungslinien

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Dr_R.Goatcabin
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Genetik der Wölfe: Hybridisierung, Introgression und Abstammungslinien

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Eine lockere Auswahl an Studien, die genetische Fragestellungen hinsichtlich Hybridisierung und anderem beim Wolf Canis lupus (und Subspecies) behandelt. Wer sich zum Superexperten weiterbilden will, hangelt sich durch die Dissertation von Hindrikson (2016) und anhängender Literaturliste dazu. ... Knock yourself out.


Andersone et al. (2002): Hybridisation between wolves and dogs in Latvia as documented using mitochondrial and microsatellite DNA markers. DOI: 10.1078/1616-5047-00012.
Abstract
Crossbreeding between wolves and dogs in the wild has been sometimes reported, but always poorly documented in scientific literature. However, documenting frequency of hybridisation and introgression is important for conservation of wild living wolf populations and for the management of free ranging dogs. Here we report the results of molecular genetic analyses of 31 wolf samples collected in Latvia from 1997 to 1999, including six pups originated from a litter found in northern Latvia in March 1999, and six wolves showing morphological traits that suggested hybrid origin. Nucleotide sequencing of the hypervariable part of the mtDNA control-region and genotyping of 16 microsatellite loci suggested that both pups and the morphologically anomalous wolves might originate from crossbreeding with dogs. Causes of wolf-dog crossbreeding, as well as possible management effort to avoid further hybridisation in the wild, are discussed.
Bensch et al. (2006): Selection for Heterozygosity Gives Hope to a Wild Population of Inbred Wolves. DOI: 10.1371/journal.pone.0000072.

Abstract
Recent analyses have questioned the usefulness of heterozygosity estimates as measures of the inbreeding coefficient (f), a finding that may have dramatic consequences for the management of endangered populations. We confirm that f and heterozygosity is poorly correlated in a wild and highly inbred wolf population. Yet, our data show that for each level of f, it was the most heterozygous wolves that established themselves as breeders, a selection process that seems to have decelerated the loss of heterozygosity in the population despite a steady increase of f. The markers contributing to the positive relationship between heterozygosity and breeding success were found to be located on different chromosomes, but there was a substantial amount of linkage disequilibrium in the population, indicating that the markers are reflecting heterozygosity over relatively wide genomic regions. Following our results we recommend that management programs of endangered populations include estimates of both f and heterozygosity, as they may contribute with complementary information about population viability.
Czarnomska et al. (2013): Concordant mitochondrial and microsatellite DNA structuring between Polish lowland and Carpathian Mountain wolves. DOI: 10.1007/s10592-013-0446-2.
Abstract
Phylogeographic studies of highly mobile large carnivores suggest that intra-specific genetic differentiation of modern species might be the consequence of the most recent Pleistocene glaciation. However, the relative influence of biogeographical processes and subsequent human-induced population fragmentation requires a better understanding. Poland represents the western edge of relatively continuous distributions of many wide-ranging species, e.g. lynx (Lynx lynx), wolves (Canis lupus), moose (Alces alces) and, therefore, a key area for understanding historic and contemporary patterns of gene flow in central Europe. We examined wolf genetic structure in Poland and in a recently recolonized area in eastern Germany using microsatellite profiles (n = 457) and mitochondrial DNA sequencing (mtDNA, n = 333) from faecal samples. We found significant genetic structure and high levels of differentiation between wolves in the Carpathian Mountains and the Polish lowlands. Our findings are consistent with previously reported mtDNA subdivision between northern lowlands and southern mountains, and add new and concordant findings based on autosomal marker variation. Wolves in western Poland and eastern Germany showed limited differentiation from northeastern Poland. Although the presence of private alleles suggests immigration also from areas not sampled in this study, most individuals seem to be immigrants from northeastern Poland or their descendants. We observed moderate genetic differentiation between certain northeastern lowland regions separated by less than 50 km. Moreover, mtDNA results indicated a southeastern subpopulation near the border with Ukraine. The observed structure might reflect landscape fragmentation and/or ecological differences resulting in natal habitat-biased dispersal.
Donfrancesco et al. (2019): Unravelling the Scientific Debate on How to Address Wolf-Dog Hybridization in Europe. DOI: 10.3389/fevo.2019.00175.
Abstract
Anthropogenic hybridization is widely perceived as a threat to the conservation of biodiversity. Nevertheless, to date, relevant policy and management interventions are unresolved and highly convoluted. While this is due to the inherent complexity of the issue, we hereby hypothesize that a lack of agreement concerning management goals and approaches, within the scientific community, may explain the lack of social awareness on this phenomenon, and the absence of effective pressure on decision-makers. By focusing on wolf x dog hybridization in Europe, we hereby (a) assess the state of the art of issues on wolf x dog hybridization within the scientific community, (b) assess the conceptual bases for different viewpoints, and (c) provide a conceptual framework aiming at reducing the disagreements. We adopted the Delphi technique, involving a three-round iterative survey addressed to a selected sample of experts who published at Web of Science listed journals, in the last 10 years on wolf x dog hybridization and related topics. Consensus was reached that admixed individuals should always be defined according to their genetic profile, and that a reference threshold for admixture (i.e., q-value in assignment tests) should be formally adopted for their identification. To mitigate hybridization, experts agreed on adopting preventive, proactive and, when concerning small and recovering wolf populations, reactive interventions. Overall, experts' consensus waned as the issues addressed became increasingly practical, including the adoption of lethal removal. We suggest three non-mutually exclusive explanations for this trend: (i) value-laden viewpoints increasingly emerge when addressing practical issues, and are particularly diverging between experts with different disciplinary backgrounds (e.g., ecologists, geneticists); (ii) some experts prefer avoiding the risk of potentially giving carte blanche to wolf opponents to (illegally) remove wolves, based on the wolf x dog hybridization issue; (iii) room for subjective interpretation and opinions result from the paucity of data on the effectiveness of different management interventions. These results have management implications and reveal gaps in the knowledge on a wide spectrum of issues related not only to the management of anthropogenic hybridization, but also to the role of ethical values and real-world management concerns in the scientific debate.
Dufresnes et al. (2019): Two decades of non-invasive genetic monitoring of the grey wolves recolonizing the Alps support very limited dog introgression. DOI: 10.1038/s41598-018-37331-x.
Abstract
Potential hybridization between wolves and dogs has fueled the sensitive conservation and political debate underlying the recovery of the grey wolf throughout Europe. Here we provide the first genetic analysis of wolf-dog admixture in an area entirely recolonized, the northwestern Alps. As part of a long-term monitoring program, we performed genetic screening of thousands of non-invasive samples collected in Switzerland and adjacent territories since the return of the wolf in the mid-1990s. We identified a total of 115 individuals, only 2 of them showing significant signs of admixture stemming from past interbreeding with dogs, followed by backcrossing. This low rate of introgression (<2% accounting for all wolves ever detected over 1998–2017) parallels those from other European populations, especially in Western Europe (<7%). Despite potential hybridization with stray dogs, few founders and strong anthropogenic pressures, the genetic integrity of the Alpine population has remained intact throughout the entire recolonization process. In a context of widespread misinformation, this finding should reduce conflicts among the different actors involved and facilitate wolf conservation. Real-time genetic monitoring will be necessary to identify potential hybrids and support an effective management of this emblematic population.
Iacolina et al. (2010): Y-chromosome microsatellite variation in Italian wolves: A contribution to the study of wolf-dog hybridization patterns. DOI: 10.1016/j.mambio.2010.02.004.
Abstract
One major concern in wolf (Canis lupus) conservation is the risk of genetic contamination due to crossbreeding with domestic dogs. Although genetic monitoring of wolf populations has become widely used, the behavioural mechanisms involved in wolf-dog hybridization and the detrimental effects of genetic introgression are poorly known. In this study we analysed Y-chromosome microsatellite variation in the recovering Italian wolf population and detected strikingly different allele frequencies between wolves and dogs. Four Y haplotypes were found in 74 analysed male wolves, and all of them were present in a focus wolf population in the Apennines. On the other hand, only 1 haplotype was found in the recolonizing wolf population from the Western Alps. The most common haplotype in a sample of domestic dogs, was also found in 5 wolves, 2 of which revealing a signature of recent hybridization. Moreover, another suspect hybrid carried a private haplotype of possible canine origin. These results give support to the idea that female wolves can breed with male stray dogs in the wild. The Y-chromosome variation in Italian wolves contrasts with the previously observed lack of mitochondrial variation. Further investigations are needed to clarify at what extent historical or recent wolf-dog hybridization events may have contributed to the observed haplotype diversity. In conclusion, the two molecular markers employed in this study represent effective means to trace directional genetic introgression into the wolves male lineage and have the noteworthy advantage of being suitable for analyses on low-quality DNA samples.
Hindrikson (2016): Grey wolf (Canis lupus) populations in Estonia and Europe: genetic diversity, population structure and -processes, and hybridization between wolves and dogs. Dissertation, http://dspace.ut.ee/handle/10062/54145.
Summary
Knowledge of wolf population genetics and hybridization between wolves and dogs are of great importance for effective conservation and management of the species at both local and global scales. There are numerous studies published on wolf population genetics in different countries and regions in Europe, however the data on Baltic population, specifically part of the population represented by Estonian and Latvian wolves, were lacking. Studies including all European countries in a comprehencive analysis of large scale spatial-genetic patterns and trends of genetic variation in Europe were also lacking. The goal of this thesis was to provide information on wolf population structure and processes in Europe with a particular emphasis on Estonia and Latvia, including the wolfdog hybridization.
Hybridization between grey wolf and domestic dog was ascertained in Estonia (for the first time) and Latvia using a combined analysis of maternal, paternal and biparental genetic markers. Six hybrid individuals from Estonia and two from Latvia were initially detected from their atypical morphological traits and their hybrid status was subsequently confirmed using genetic analysis. Analysis of mtDNA showed that the two hybrids from Latvia represented a very rare case of hybridization – the first record from Europe – between a female dog and a male wolf.
Population genetic analysis demonstrated that the relatively small wolf population shared between Estonia and Latvia is represented by four genetic groups. While three of the four genetic groups were geographically well defined, being either Estonian or Latvian based, one of the groups was distributed widely in Estonia and Latvia. The spatially explicit DResD analysis provided clear evidence of spatial variation of genetic divergence: (a) at the smallest spatial scale (20–80 km) several blending areas of different groups appeared with relatively high genetic distance between otherwise geographically closely positioned individuals; (b): at the medium scale (80–140 km) a putative territory of an expanding pack was detected in south-west Estonia, coinciding with one of the core areas of group D (c): at the largest spatial scale (140–250 km) a large area in the northeastern part of Estonia was identified as a migration corridor.
To describe large-scale trends and patterns of genetic variation in European wolf populations, we conducted a meta-analysis based on the results of previous microsatellite studies and included also new data, covering all 19 European countries for which wolf genetic information is available: Norway, Sweden, Finland, Estonia, Latvia, Lithuania, Poland, Czech Republic, Slovakia, Germany, Belarus, Russia, Italy, Croatia, Bulgaria, Bosnia and Herzegovina, Greece, Spain and Portugal. We compared different indices of genetic diversity in wolf populations and found a significant spatial trend in heterozygosity across Europe from south-west (lowest genetic diversity) to north-east (highest). The range of spatial autocorrelation calculated on the basis of three characteristics of genetic28 diversity was 650−850 km, suggesting that the genetic diversity of a given wolf population can be influenced by populations up to 850 km away.
Various human-related factors are undoubtedly the main source of threats to wolf populations in Europe: the majority of populations face similar common threats such as overharvesting (including poaching), low public acceptance, conflicts due to livestock depredation, habitat destruction, barriers to gene flow and interactions with dogs leading to possible hybridization. For the long-term survival and favourable conservation status of European wolves there is a need to increase the overall population size and favour wolf dispersal and connectivity among and within populations. For science-based wolf conservation and management at regional and Europe-wide scales it was suggested (1) to manage wolf populations according to biological units, which requires additional genetic analysis covering all wolf populations in Europe to define the exact number and spatial distribution of populations; (2) to increase scientific knowledge and inform stakeholders and the general public, there is a need to establish a European Union Wolf Scientific Committee and a European Union Reference Laboratory of Wolf Studies.
Hindrikson et al. (2012): Bucking the Trend in Wolf-Dog Hybridization: First Evidence from Europe of Hybridization between Female Dogs and Male Wolves. DOI: 10.1371/journal.pone.0046465.
Abstract
Studies on hybridization have proved critical for understanding key evolutionary processes such as speciation and adaptation. However, from the perspective of conservation, hybridization poses a concern, as it can threaten the integrity and fitness of many wild species, including canids. As a result of habitat fragmentation and extensive hunting pressure, gray wolf (Canis lupus) populations have declined dramatically in Europe and elsewhere during recent centuries. Small and fragmented populations have persisted, but often only in the presence of large numbers of dogs, which increase the potential for hybridization and introgression to deleteriously affect wolf populations. Here, we demonstrate hybridization between wolf and dog populations in Estonia and Latvia, and the role of both genders in the hybridization process, using combined analysis of maternal, paternal and biparental genetic markers. Eight animals exhibiting unusual external characteristics for wolves - six from Estonia and two from Latvia - proved to be wolf-dog hybrids. However, one of the hybridization events was extraordinary. Previous field observations and genetic studies have indicated that mating between wolves and dogs is sexually asymmetrical, occurring predominantly between female wolves and male dogs. While this was also the case among the Estonian hybrids, our data revealed the existence of dog mitochondrial genomes in the Latvian hybrids and, together with Y chromosome and autosomal microsatellite data, thus provided the first evidence from Europe of mating between male wolves and female dogs. We discuss patterns of sexual asymmetry in wolf-dog hybridization.
Hindrikson et al. (2017): Wolf population genetics in Europe: a systematic review, meta-analysis and suggestions for conservation and management: Wolf population genetics in Europe. DOI: 10.1111/brv.12298.
Abstract
The grey wolf (Canis lupus) is an iconic large carnivore that has increasingly been recognized as an apex predator with intrinsic value and a keystone species. However, wolves have also long represented a primary source of human–carnivore conflict, which has led to long‐term persecution of wolves, resulting in a significant decrease in their numbers, genetic diversity and gene flow between populations. For more effective protection and management of wolf populations in Europe, robust scientific evidence is crucial. This review serves as an analytical summary of the main findings from wolf population genetic studies in Europe, covering major studies from the ‘pre‐genomic era’ and the first insights of the ‘genomics era’. We analyse, summarize and discuss findings derived from analyses of three compartments of the mammalian genome with different inheritance modes: maternal (mitochondrial DNA), paternal (Y chromosome) and biparental [autosomal microsatellites and single nucleotide polymorphisms (SNPs)]. To describe large‐scale trends and patterns of genetic variation in European wolf populations, we conducted a meta‐analysis based on the results of previous microsatellite studies and also included new data, covering all 19 European countries for which wolf genetic information is available: Norway, Sweden, Finland, Estonia, Latvia, Lithuania, Poland, Czech Republic, Slovakia, Germany, Belarus, Russia, Italy, Croatia, Bulgaria, Bosnia and Herzegovina, Greece, Spain and Portugal. We compared different indices of genetic diversity in wolf populations and found a significant spatial trend in heterozygosity across Europe from south‐west (lowest genetic diversity) to north‐east (highest). The range of spatial autocorrelation calculated on the basis of three characteristics of genetic diversity was 650−850 km, suggesting that the genetic diversity of a given wolf population can be influenced by populations up to 850 km away. As an important outcome of this synthesis, we discuss the most pressing issues threatening wolf populations in Europe, highlight important gaps in current knowledge, suggest solutions to overcome these limitations, and provide recommendations for science‐based wolf conservation and management at regional and Europe‐wide scales.
Gottelli et al. (1994): Molecular genetics of the most endangered canid: the Ethiopian wolf Canis simensis. DOI: 10.1111/j.1365-294X.1994.tb00070.x.
Abstract
The world's most endangered canid is the Ethiopian wolf Canis simensis, which is found in six isolated areas of the Ethiopian highlands with a total population of no more than 500 individuals. Ethiopian wolf populations are declining due to habitat loss and extermination by humans. Moreover, in at least one population, Ethiopian wolves are sympatric with domestic dogs, which may hybridize with them, compete for food, and act as disease vectors. Using molecular techniques, we address four questions concerning Ethiopian wolves that have conservation implications. First, we determine the relationships of Ethiopian wolves to other wolf‐like canids by phylogenetic analysis of 2001 base pairs of mitochondrial DNA (mtDNA) sequence. Our results suggest that the Ethiopian wolf is a distinct species more closely related to gray wolves and coyotes than to any African canid. The mtDNA sequence similarity with gray wolves implies that the Ethiopian wolf may hybridize with domestic dogs, a recent derivative of the gray wolf. We examine this possibility through mtDNA restriction fragment analysis and analysis of nine microsatellite loci in populations of Ethiopian wolves. The results imply that hybridization has occurred between female Ethiopian wolves and male domestic dogs in one population. Finally, we assess levels of variability within and between two Ethiopian wolf populations. Although these closely situated populations are not differentiated, the level of variability in both is low, suggesting long‐term effective population sizes of less than a few hundred individuals. We recommend immediate captive breeding of Ethiopian wolves to protect their gene pool from dilution and further loss of genetic variability.
Kraus et al. (2015): A single-nucleotide polymorphism-based approach for rapid and cost-effective genetic wolf monitoring in Europe based on noninvasively collected samples. DOI: 10.1111/1755-0998.12307.
Abstract
Noninvasive genetics based on microsatellite markers has become an indispensable tool for wildlife monitoring and conservation research over the past decades. However, microsatellites have several drawbacks, such as the lack of standardisation between laboratories and high error rates. Here, we propose an alternative single‐nucleotide polymorphism (SNP)‐based marker system for noninvasively collected samples, which promises to solve these problems. Using nanofluidic SNP genotyping technology (Fluidigm), we genotyped 158 wolf samples (tissue, scats, hairs, urine) for 192 SNP loci selected from the Affymetrix v2 Canine SNP Array. We carefully selected an optimised final set of 96 SNPs (and discarded the worse half), based on assay performance and reliability. We found rates of missing data in this SNP set of <10% and genotyping error of ~1%, which improves genotyping accuracy by nearly an order of magnitude when compared to published data for other marker types. Our approach provides a tool for rapid and cost‐effective genotyping of noninvasively collected wildlife samples. The ability to standardise genotype scoring combined with low error rates promises to constitute a major technological advancement and could establish SNPs as a standard marker for future wildlife monitoring.
Lucchini et al. (2004): Evidence of genetic distinction and long-term population decline in wolves (Canis lupus) in the Italian Apennines. DOI: 10.1046/j.1365-294X.2004.02077.x.
Abstract
Historical information suggests the occurrence of an extensive human‐caused contraction in the distribution range of wolves (Canis lupus) during the last few centuries in Europe. Wolves disappeared from the Alps in the 1920s, and thereafter continued to decline in peninsular Italy until the 1970s, when approximately 100 individuals survived, isolated in the central Apennines. In this study we performed a coalescent analysis of multilocus DNA markers to infer patterns and timing of historical population changes in wolves surviving in the Apennines. This population showed a unique mitochondrial DNA control‐region haplotype, the absence of private alleles and lower heterozygosity at microsatellite loci, as compared to other wolf populations. Multivariate, clustering and Bayesian assignment procedures consistently assigned all the wolf genotypes sampled in Italy to a single group, supporting their genetic distinction. Bottleneck tests showed evidences of population decline in the Italian wolves, but not in other populations. Results of a Bayesian coalescent model indicate that wolves in Italy underwent a 100‐ to 1000‐fold population contraction over the past 2000–10 000 years. The population decline was stronger and longer in peninsular Italy than elsewhere in Europe, suggesting that wolves have apparently been genetically isolated for thousands of generations south of the Alps. Ice caps covering the Alps at the Last Glacial Maximum (c. 18 000 years before present), and the wide expansion of the Po River, which cut the alluvial plains throughout the Holocene, might have provided effective geographical barriers to wolf dispersal. More recently, the admixture of Alpine and Apennine wolf populations could have been prevented by deforestation, which was already widespread in the fifteenth century in northern Italy. This study suggests that, despite the high potential rates of dispersal and gene flow, local wolf populations may not have mixed for long periods of time.
McFarlane & Pemberton (2019): Detecting the True Extent of Introgression during Anthropogenic Hybridization. DOI: 10.1016/j.tree.2018.12.013.
Abstract
Anthropogenic hybridization is increasingly common and is likely to result in a breakdown of reproductive isolation between ‘good’ species.
Backcrossed individuals that have only a small proportion of one parental genome are difficult to differentiate from parental individuals by using the most common current technologies.
Bimodal hybrid zones are characterized by introgression and backcrossing. The majority of hybrid individuals in these systems have low levels of introgression. The problems posed by bimodal hybrid zones have been largely overlooked in the literature.
Genome-wide sampling of genetic markers at high densities allow increased precision in the estimate of admixture proportions, which makes it feasible to detect multi-generation backcrosses, and will thus make it easier to differentiate bimodal hybrid zones from hybrid swarms or systems without introgression.
Hybridization among naturally separate taxa is increasing owing to human impact, and can result in taxon loss. Previous classification of anthropogenic hybridization has largely ignored the case of bimodal hybrid zones, in which hybrids commonly mate with parental species, resulting in many backcrossed individuals with a small proportion of introgressed genome. Genetic markers can be used to detect such hybrids, but until recently too few markers have been used to detect the true extent of introgression. Recent studies of wolves and trout have employed thousands of markers to reveal previously undetectable backcrosses. This improved resolution will lead to increased detection of late-generation backcrosses, shed light on the consequences of anthropogenic hybridization, and pose new management issues for conservation scientists.
Mech et al. (2017): Studies of wolf x coyote hybridization via artificial insemination. DOI: 10.1371/journal.pone.0184342.
Abstract
Following the production of western gray wolf (Canis lupus) x western coyote (Canis latrans) hybrids via artificial insemination (AI), the present article documents that the hybrids survived in captivity for at least 4 years and successfully bred with each other. It further reports that backcrossing one of the hybrids to a male gray wolf by AI also resulted in the birth of live pups that have survived for at least 10 months. All male hybrids (F1 and F2) produced sperm by about 10 months of age, and sperm quality of the F1 males fell within the fertile range for domestic dogs, but sperm motility and morphology, in particular, were low in F2 males at 10 months but improved in samples taken at 22 months of age. These studies are relevant to a long-standing controversy about the identity of the red wolf (Canis rufus), the existence of a proposed new species (Canis lycaon) of gray wolf, and to the role of hybridization in mammalian evolution.
Mech et al. (2014): Production of Hybrids between Western Gray Wolves and Western Coyotes. DOI: 10.1371/journal.pone.0088861.
Abstract
Using artificial insemination we attempted to produce hybrids between captive, male, western, gray wolves (Canis lupus) and female, western coyotes (Canis latrans) to determine whether their gametes would be compatible and the coyotes could produce and nurture offspring. The results contribute new information to an ongoing controversy over whether the eastern wolf (Canis lycaon) is a valid unique species that could be subject to the U. S. Endangered Species Act. Attempts with transcervically deposited wolf semen into nine coyotes over two breeding seasons yielded three coyote pregnancies. One coyote ate her pups, another produced a resorbed fetus and a dead fetus by C-section, and the third produced seven hybrids, six of which survived. These results show that, although it might be unlikely for male western wolves to successfully produce offspring with female western coyotes under natural conditions, western-gray-wolf sperm are compatible with western-coyote ova and that at least one coyote could produce and nurture hybrid offspring. This finding in turn demonstrates that gamete incompatibility would not have prevented western, gray wolves from inseminating western coyotes and thus producing hybrids with coyote mtDNA, a claim that counters the view that the eastern wolf is a separate species. However, some of the difficulties experienced by the other inseminated coyotes tend to temper that finding and suggest that more experimentation is needed, including determining the behavioral and physical compatibility of western gray wolves copulating with western coyotes. Thus although our study adds new information to the controversy, it does not settle it. Further study is needed to determine whether the putative Canis lycaon is indeed a unique species.
Mellersh et al. (1997): A Linkage Map of the Canine. DOI: 10.1006/geno.1997.5098.

Abstract
A genetic linkage map of the canine genome has been developed by typing 150 microsatellite markers using 17 three-generation pedigrees, composed of 163 F2individuals. One hundred and thirty-nine markers were linked to at least one other marker with a lod score ≥ 3.0, identifying 30 linkage groups. The largest chromosome had 9 markers spanning 106.1 cM. The average distance between markers was 14.03 cM, and the map covers an estimated 2073 cM. Eleven markers were informative on the mapping panel, but were unlinked to any other marker. These likely represent single markers located on small, distinct canine chromosomes. This map will be the initial resource for mapping canine traits of interest and serve as a foundation for development of a comprehensive canine genetic map.
Moura et al. (2014): Unregulated hunting and genetic recovery from a severe population decline: the cautionary case of Bulgarian wolves. DOI: 10.1007/s10592-013-0547-y.

Abstract
European wolf (Canis lupus) populations have suffered extensive decline and range contraction due to anthropogenic culling. In Bulgaria, although wolves are still recovering from a severe demographic bottleneck in the 1970s, hunting is allowed with few constraints. A recent increase in hunting pressure has raised concerns regarding long-term viability. We thus carried out a comprehensive conservation genetic analysis using microsatellite and mtDNA markers. Our results showed high heterozygosity levels (0.654, SE 0.031) and weak genetic bottleneck signals, suggesting good recovery since the 1970s decline. However, we found high levels of inbreeding (F IS = 0.113, SE 0.019) and a N e/N ratio lower than expected for an undisturbed wolf population (0.11, 95 % CI 0.08–0.29). We also found evidence for hybridisation and introgression from feral dogs (C. familiaris) in 10 out of 92 wolves (9.8 %). Our results also suggest admixture between wolves and local populations of golden jackals (C. aureus), but less extensive as compared with the admixture with dogs. We detected local population structure that may be explained by fragmentation patterns during the 1970s decline and differences in local ecological characteristics, with more extensive sampling needed to assess further population substructure. We conclude that high levels of inbreeding and hybridisation with other canid species, which likely result from unregulated hunting, may compromise long-term viability of this population despite its current high genetic diversity. The existence of population subdivision warrants an assessment of whether separate management units are needed for different subpopulations. Our study highlights conservation threats for populations with growing numbers but subject to unregulated hunting.
Peltola & Heikkilä, Jari (2018): Outlaws or Protected? DNA, Hybrids, and Biopolitics in a Finnish Wolf-Poaching Case. DOI: 10.1163/15685306-12341509.

Abstract
By analyzing a 2015 Finnish court case on wolf poaching, we discuss how wild animals are categorized, gain legal status based on their species identification, and affect the categorization of humans either as poachers or hunters concerned about the genetic purity of the species. The court had to evaluate the reliability, accuracy, and relevance of scientific knowledge to distinguish “pure” wolves from hybrids. Dealing with complicated questions of canid species identification, the court decision took a position in the debate on what to conserve in a world which escapes simple categorizations. Hence, we interpret the case as an example of biopolitics, addressing the challenges and tensions of governing life by differentiating between valued and less valued, killable and threatened lifeforms, and human responsibilities towards them.
Pilot et al. (2018): Widespread, long-term admixture between grey wolves and domestic dogs across Eurasia and its implications for the conservation status of hybrids. DOI: 10.1111/eva.12595.

Abstract
Hybridisation between a domesticated species and its wild ancestor is an important conservation problem, especially if it results in the introgression of domestic gene variants into wild species. Nevertheless, the legal status of hybrids remains unregulated, partially because of the limited understanding of the hybridisation process and its consequences. The occurrence of hybridisation between grey wolves and domestic dogs is well documented from different parts of the wolf geographic range, but little is known about the frequency of hybridisation events, their causes and the genetic impact on wolf populations. We analysed 61K SNPs spanning the canid genome in wolves from across Eurasia and North America and compared that data to similar data from dogs to identify signatures of admixture. The haplotype block analysis, which included 38 autosomes and the X chromosome, indicated the presence of individuals of mixed wolf–dog ancestry in most Eurasian wolf populations, but less admixture was present in North American populations. We found evidence for male‐biased introgression of dog alleles into wolf populations, but also identified a first‐generation hybrid resulting from mating between a female dog and a male wolf. We found small blocks of dog ancestry in the genomes of 62% Eurasian wolves studied and melanistic individuals with no signs of recent admixed ancestry, but with a dog‐derived allele at a locus linked to melanism. Consequently, these results suggest that hybridisation has been occurring in different parts of Eurasia on multiple timescales and is not solely a recent phenomenon. Nevertheless, wolf populations have maintained genetic differentiation from dogs, suggesting that hybridisation at a low frequency does not diminish distinctiveness of the wolf gene pool. However, increased hybridisation frequency may be detrimental for wolf populations, stressing the need for genetic monitoring to assess the frequency and distribution of individuals resulting from recent admixture.
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Dr_R.Goatcabin
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Re: Genetik der Wölfe: Hybridisierung, Introgression und Abstammungslinien

Beitrag von Dr_R.Goatcabin »

Randi & Lucchini (2002): Detecting rare introgression of domestic dog genes into wild wolf (Canis lupus) populations by Bayesian admixture analyses of microsatellite variation. DOI: 10.1023/A:1014229610646.
Abstract
Hybridization with free-ranging dogs isthought to threat the genetic integrity ofwolves in Europe, although available mtDNA dataevidenced only sporadic cases of crossbreeding.Here we report results of population assignmentand genetic admixture analyses in 107wild-living Italian wolves, 95 dogs including30 different breeds and feral dogs, andcaptive-reared wolves of unknown or hybridorigins, which were genotyped at 18microsatellites. Two Italian wolves showedunusually dark coats (``black wolves''), and oneshowed a spur in both hindlegs (``fifth fingerwolf''), suggesting hybridization. Italianwolves showed significant deficit ofheterozygotes, positive FIS values anddeviations from Hardy-Weinberg equilibrium.Genetic variability was significantlypartitioned between groups, suggesting thatwolves and dogs represent distinct gene pools.Multivariate ordination of individual genotypesand clustering of inter-individual geneticdistances split wolves and dogs into twodifferent clusters congruent with the priorphenotypic classification, but hybrids andwolves of unknown origin were not identifiedfrom genetic information alone. By contrast, aBayesian admixture analysis assigned all theItalian wolves and dogs to two differentclusters, independent of any prior phenotypicinformation, and simultaneously detected theadmixed gene composition of the hybrids, whichwere assigned to more than one cluster.Captive-reared wolves of unknown origin wereprevalently assigned to the Italian wolfpopulation. Admixture analyses showed that one``black wolf'' had mixed ancestry in the dog genepool and could be a hybrid, while the other twowolves with unusual phenotypes were assigned tothe Italian wolf population.
Randi & Lucchini (2009): Mitochondrial DNA restriction-fragment-length monomorphism in the Italian wolf (Canis lupus) population. DOI: 10.1111/j.1439-0469.1995.tb00215.x.
Abstract
Mitochondrial‐DNA (mtDNA) restriction patterns were studied in 22 wolves (Canis lupus) sampled in central‐northern Italy. A total of 60 restriction sites were detected, encompassing about 2 % of the mitochondrial genome of canids. All wolves showed the same restriction pattern. Therefore, a single mtDNA haplotype was detected in the Italian wolf population. Historical information on peninsular isolation and demographic decline suggest that low genetically effective population size and random drift may have strongly reduced the mtDNA variability of wolves in Italy over the last 100–200 years. A different mtDNA restriction pattern in feral dogs sampled from a wolf range in central Italy was detected. These findings suggest that the hybridization and introgression of female dog genomes into the Italian wolf population may be rare or absent.
Randi (2011): Genetics and conservation of wolves Canis lupus in Europe: Wolf conservation genetics. DOI: 10.1111/j.1365-2907.2010.00176.x.
Abstract
The wolf Canis lupus, the most widespread of the four species of large carnivores in Europe, after centuries of population decline and eradication, is now recovering in many countries. Wolves contribute to regulating prey–predator dynamics and interact with human activities, mainly livestock farming and ungulate hunting. Although wolves are protected in most European countries, illegal or incidental killing is widespread.

Wolf populations do not show any apparent phylogeographic structuring worldwide. Molecular and morphological studies of historical samples showed evidence of wolf ecomorph extinctions, coinciding with the great Pleistocene faunal turnover.

Extant populations show recurrent long‐range dispersal during cycles of expansion and recolonization. Demographically stable populations, in contrast, seem to be characterized by very limited gene flow.

Despite the potential for dispersal and ecological flexibility, landscape genetic approaches have demonstrated the existence of genetically distinct wolf populations, which originated through habitat and prey specializations.

Small isolated wolf populations may suffer from inbreeding depression, although selection for heterozygotes and the rescue effect can foster rapid population recovery. Population structure and dynamics is efficiently monitored by non‐invasive genetic methods, which are also useful to identify wolf × dogCanis lupus familiaris hybridization.

Despite technical advances and a better knowledge of wolf biology, wolf conservation is largely dependent on humans, and on the solution of conflicts with stakeholders.
Randi et al. (2000): Mitochondrial DNA Variability in Italian and East European Wolves: Detecting the Consequences of Small Population Size and Hybridization. DOI: 10.1046/j.1523-1739.2000.98280.x.
Abstract
The Italian wolf (Canis lupus) population has declined continuously over the last few centuries and become isolated as a result of the extermination of other populations in central Europe and the Alps during the nineteenth century. In the 1970s, approximately 100 wolves survived in 10 isolated areas in the central and southern Italian Apennines. Loss of genetic variability, as suggested by preliminary studies of mitochondrial DNA (mtDNA) sequences, hybridization with feral dogs, and the illegal release of captive, non‐native wolves are considered potential threats to the viability of the Italian wolf population. We sequenced 546 base pairs of the mtDNA control region in a comprehensive set of Italian wolves and compared them to those of dogs and other wolf populations from Europe and the Near East. Our data confirm the absence of mtDNA variability in Italian wolves: all 101 individuals sampled across their distribution in Italy had the same, unique haplotype, whereas seven haplotypes were found in only 26 wolves from an outbred population in Bulgaria. Most haplotypes were specific either to wolves or dogs, but some east European wolves shared haplotypes with dogs, indicative of hybridization. In contrast, neither hybridization with dogs nor introgression of non‐native wolves was detected in the Italian population. These findings exclude the introgression of dog genes via matings between male wolves and female dogs, the most likely direction of hybridization. The observed mtDNA monomorphism is the possible outcome of random drift in the declining and isolated Italian wolf population, which probably existed at low effective population size during the last 100–150 years. Low effective population size and the continued loss of genetic variability might be a major threat to the long‐term viability of Italian wolves. A controlled demographic increase, leading to recolonization of the historical wolf range in Italy, should be enforced.
Randi et al. (2014): Multilocus Detection of Wolf x Dog Hybridization in Italy, and Guidelines for Marker Selection. DOI: 10.1371/journal.pone.0086409.

Abstract
Hybridization and introgression can impact the evolution of natural populations. Several wild canid species hybridize in nature, sometimes originating new taxa. However, hybridization with free-ranging dogs is threatening the genetic integrity of grey wolf populations (Canis lupus), or even the survival of endangered species (e.g., the Ethiopian wolf C. simensis). Efficient molecular tools to assess hybridization rates are essential in wolf conservation strategies. We evaluated the power of biparental and uniparental markers (39 autosomal and 4 Y-linked microsatellites, a melanistic deletion at the β-defensin CBD103 gene, the hypervariable domain of the mtDNA control-region) to identify the multilocus admixture patterns in wolf x dog hybrids. We used empirical data from 2 hybrid groups with different histories: 30 presumptive natural hybrids from Italy and 73 Czechoslovakian wolfdogs of known hybrid origin, as well as simulated data. We assessed the efficiency of various marker combinations and reference samples in admixture analyses using 69 dogs of different breeds and 99 wolves from Italy, Balkans and Carpathian Mountains. Results confirmed the occurrence of hybrids in Italy, some of them showing anomalous phenotypic traits and exogenous mtDNA or Y-chromosome introgression. Hybridization was mostly attributable to village dogs and not strictly patrilineal. The melanistic β-defensin deletion was found only in Italian dogs and in putative hybrids. The 24 most divergent microsatellites (largest wolf-dog FST values) were equally or more informative than the entire panel of 39 loci. A smaller panel of 12 microsatellites increased risks to identify false admixed individuals. The frequency of F1 and F2 was lower than backcrosses or introgressed individuals, suggesting hybridization already occurred some generations in the past, during early phases of wolf expansion from their historical core areas. Empirical and simulated data indicated the identification of the past generation backcrosses is always uncertain, and a larger number of ancestry-informative markers is needed.
Rutledge et al. (2012): Intense harvesting of eastern wolves facilitated hybridization with coyotes: Culling Facilitates Hybridization. DOI: 10.1002/ece3.61.

Abstract
Despite ethical arguments against lethal control of wildlife populations, culling is routinely used for the management of predators, invasive or pest species, and infectious diseases. Here, we demonstrate that culling of wildlife can have unforeseen impacts that can be detrimental to future conservation efforts. Specifically, we analyzed genetic data from eastern wolves (Canis lycaon) sampled in Algonquin Provincial Park (APP), Ontario, Canada from 1964 to 2007. Research culls in 1964 and 1965 killed the majority of wolves within a study region of APP, accounting for approximately 36% of the park's wolf population at a time when coyotes were colonizing the region. The culls were followed by a significant decrease in an eastern wolf mitochondrial DNA (mtDNA) haplotype (C1) in the Park's wolf population, as well as an increase in coyote mitochondrial and nuclear DNA. The introgression of nuclear DNA from coyotes, however, appears to have been curtailed by legislation that extended wolf protection outside park boundaries in 2001, although eastern wolf mtDNA haplotype C1 continued to decline and is now rare within the park population. We conclude that the wolf culls transformed the genetic composition of this unique eastern wolf population by facilitating coyote introgression. These results demonstrate that intense localized harvest of a seemingly abundant species can lead to unexpected hybridization events that encumber future conservation efforts. Ultimately, researchers need to contemplate not only the ethics of research methods, but also that future implications may be obscured by gaps in our current scientific understanding.
Salvatori et al. (2019): High levels of recent wolf × dog introgressive hybridization in agricultural landscapes of central Italy. DOI: 10.1007/s10344-019-1313-3.

Abstract
Representing a form of anthropogenic hybridization, wolf–dog interbreeding may potentially compromise the ecological and evolutionary traits of local wolf populations and corrode social tolerance towards wolves. However, estimates of the extent of wolf–dog hybridization in wolf populations are scarce, especially at a multi-pack scale and in human-dominated landscapes. Using non-invasive (n = 215) and invasive (n = 25) samples of wolf-like canids collected in the Province of Grosseto (central Italy, 2012–2014), we assessed the extent of wolf–dog hybridization based on multi-locus genotypes (16 and 49 loci for non-invasive and invasive samples, respectively) and Bayesian clustering techniques. Based on a total of 72 genotypes, the minimum proportion of admixed individuals in our sample was 30.6%, comprising 8 out of the 13 surveyed packs; however, by correcting for the proportion of admixed individuals undetected using the 16-loci compared with the 49-loci marker set (26.7%), we suspect the rate of recent admixture could be closer to 50%. While we did not detect any F1 hybrid, four admixed individuals had a non-negligible probability of being first-generation backcrosses, one of which likely derived from a backcross of a F1 hybrid into the dog population. Complementary genetic markers (i.e., Y-haplotype and K-locus) or anomalous morphological traits further indicated widespread occurrence of admixed individuals of older generations of backcross. This high level of admixture raises serious wolf conservation concerns and exemplifies the expected dynamics of wolf–dog hybridization if left unmanaged in human-dominated landscapes. The implications of our findings need to be urgently upscaled for the implementation of management interventions that cannot be procrastinated any longer at the regional and national scale.
Smeds et al. (2019): The evolutionary history of grey wolf Y chromosomes. DOI: 10.1111/mec.15054.

Abstract
Analyses of Y chromosome haplotypes uniquely provide a paternal picture of evolutionary histories and offer a very useful contrast to studies based on maternally inherited mitochondrial DNA (mtDNA). Here we used a bioinformatic approach based on comparison of male and female sequence coverage to identify 4.7 Mb from the grey wolf (Canis lupis) Y chromosome, probably representing most of the male‐specific, nonampliconic sequence from the euchromatic part of the chromosome. We characterized this sequence and then identified ≈1,500 Y‐linked single nucleotide polymorphisms in a sample of 145 resequenced male wolves, including 75 Finnish wolf genomes newly sequenced in this study, and in 24 dogs and eight other canids. We found 53 Y chromosome haplotypes, of which 26 were seen in grey wolves, that clustered in four major haplogroups. All four haplogroups were represented in samples of Finnish wolves, showing that haplogroup lineages were not partitioned on a continental scale. However, regional population structure was indicated because individual haplotypes were never shared between geographically distant areas, and genetically similar haplotypes were only found within the same geographical region. The deepest split between grey wolf haplogroups was estimated to have occurred 125,000 years ago, which is considerably older than recent estimates of the time of divergence of wolf populations. The distribution of dogs in a phylogenetic tree of Y chromosome haplotypes supports multiple domestication events, or wolf paternal introgression, starting 29,000 years ago. We also addressed the disputed origin of a recently founded population of Scandinavian wolves and observed that founding as well as most recent immigrant haplotypes were present in the neighbouring Finnish population, but not in sequenced wolves from elsewhere in the world, or in dogs.
Stronen et al. (2013): Perspectives on the conservation of wild hybrids. DOI: 10.1016/j.biocon.2013.09.004.

Abstract
Hybridization processes are widespread throughout the taxonomic range and require conservation recognition. Science can help us understand hybridization processes but not whether and when we ought to conserve hybrids. Important questions include the role of humans in hybridization and the value we place on natural and human-induced hybrids concerning their ecological function. Certain hybrids resulting from human actions have replaced the ecological role of extirpated or extinct parent taxa and this ecological role should be preserved. Conservation policies must increasingly recognize populations of wild organisms that hybridize naturally within the context of their historical ecological role. Natural selection acts on individual organisms and the range of characteristics displayed by individual hybrids constitute raw material for evolution. Guidelines must consider the conservation value of individuals and the ethical aspects of removing hybrids for the purpose of conserving population genetic integrity. Conservation policies should focus on protecting the ecological role of taxa affected by hybridization. An informative example is North American canids (Canis), where body size, prey availability, and human landscape modifications may interact and impose local selective pressures. Gray wolves (Canis lupus) and eastern wolves (Canis lycaon or Canis lupus lycaon) or Great Lakes wolves appear to hybridize naturally within the context of their historical ecological role. In contrast, eastern coyotes (C. latrans) exhibit wolf ancestry and have partly replaced the ecological role of an extirpated parent taxa in parts of northeastern North America. The need for advancing conservation policies that reflect our current understanding of ecology and evolution is urgent.
Stronen et al. (2013): North-South Differentiation and a Region of High Diversity in European Wolves (Canis lupus). DOI: 10.1371/journal.pone.0076454.

Abstract
European wolves (Canis lupus) show population genetic structure in the absence of geographic barriers, and across relatively short distances for this highly mobile species. Additional information on the location of and divergence between population clusters is required, particularly because wolves are currently recolonizing parts of Europe. We evaluated genetic structure in 177 wolves from 11 countries using over 67K single nucleotide polymorphism (SNP) loci. The results supported previous findings of an isolated Italian population with lower genetic diversity than that observed across other areas of Europe. Wolves from the remaining countries were primarily structured in a north-south axis, with Croatia, Bulgaria, and Greece (Dinaric-Balkan) differentiated from northcentral wolves that included individuals from Finland, Latvia, Belarus, Poland and Russia. Carpathian Mountain wolves in central Europe had genotypes intermediate between those identified in northcentral Europe and the Dinaric-Balkan cluster. Overall, individual genotypes from northcentral Europe suggested high levels of admixture. We observed high diversity within Belarus, with wolves from western and northern Belarus representing the two most differentiated groups within northcentral Europe. Our results support the presence of at least three major clusters (Italy, Carpathians, Dinaric-Balkan) in southern and central Europe. Individuals from Croatia also appeared differentiated from wolves in Greece and Bulgaria. Expansion from glacial refugia, adaptation to local environments, and human-related factors such as landscape fragmentation and frequent killing of wolves in some areas may have contributed to the observed patterns. Our findings can help inform conservation management of these apex predators and the ecosystems of which they are part.
Taylor et al. (2019): Insights from genomes into the evolutionary importance and prevalence of hybridization in nature. DOI: 10.1038/s41559-018-0777-y.

Abstract
Hybridization is an evolutionary phenomenon that has fascinated biologists for centuries. Prior to the advent of whole-genome sequencing, it was clear that hybridization had played a role in the evolutionary history of many extant taxa, particularly plants. The extent to which hybridization has contributed to the evolution of Earth’s biodiversity has, however, been the topic of much debate. Analyses of whole genomes are providing further insight into this evolutionary problem. Recent studies have documented ancient hybridization in a diverse array of taxa including mammals, birds, fish, fungi, and insects. Evidence for adaptive introgression is being documented in an increasing number of systems, though demonstrating the adaptive function of introgressed genomic regions remains difficult. And finally, several new homoploid hybrid speciation events have been reported. Here we review the current state of the field and specifically evaluate the additional insights gained from having access to whole-genome data and the challenges that remain with respect to understanding the evolutionary relevance and frequency of ancient hybridization, adaptive introgression, and hybrid speciation in nature.
Verardi et al. (2006): Detecting introgressive hybridization between free-ranging domestic dogs and wild wolves (Canis lupus) by admixture linkage disequilibrium analysis: HYBRIDIZATION IN ITALIAN WOLVES and DOGS. DOI: 10.1111/j.1365-294X.2006.02995.x.

Abstract
Occasional crossbreeding between free‐ranging domestic dogs and wild wolves (Canis lupus) has been detected in some European countries by mitochondrial DNA sequencing and genotyping unlinked microsatellite loci. Maternal and unlinked genomic markers, however, might underestimate the extent of introgressive hybridization, and their impacts on the preservation of wild wolf gene pools. In this study, we genotyped 220 presumed Italian wolves, 85 dogs and 7 known hybrids at 16 microsatellites belonging to four different linkage groups (plus four unlinked microsatellites). Population clustering and individual assignments were performed using a Bayesian procedure implemented in structure 2.1, which models the gametic disequilibrium arising between linked loci during admixtures, aiming to trace hybridization events further back in time and infer the population of origin of chromosomal blocks. Results indicate that (i) linkage disequilibrium was higher in wolves than in dogs; (ii) 11 out of 220 wolves (5.0%) were likely admixed, a proportion that is significantly higher than one admixed genotype in 107 wolves found previously in a study using unlinked markers; (iii) posterior maximum‐likelihood estimates of the recombination parameter r revealed that introgression in Italian wolves is not recent, but could have continued for the last 70 (± 20) generations, corresponding to approximately 140–210 years. Bayesian clustering showed that, despite some admixture, wolf and dog gene pools remain sharply distinct (the average proportions of membership to wolf and dog clusters were Qw = 0.95 and Qd = 0.98, respectively), suggesting that hybridization was not frequent, and that introgression in nature is counteracted by behavioural or selective constraints.
Vilà et al. (2003): Combined use of maternal, paternal and bi-parental genetic markers for the identification of wolf–dog hybrids. DOI: 10.1038/sj.hdy.6800175.

Abstract
The identification of hybrids is often a subject of primary concern for the development of conservation and management strategies, but can be difficult when the hybridizing species are closely related and do not possess diagnostic genetic markers. However, the combined use of mitochondrial DNA (mtDNA), autosomal and Y chromosome genetic markers may allow the identification of hybrids and of the direction of hybridization. We used these three types of markers to genetically characterize one possible wolf–dog hybrid in the endangered Scandinavian wolf population. We first characterized the variability of mtDNA and Y chromosome markers in Scandinavian wolves as well as in neighboring wolf populations and in dogs. While the mtDNA data suggested that the target sample could correspond to a wolf, its Y chromosome type had not been observed before in Scandinavian wolves. We compared the genotype of the target sample at 18 autosomal microsatellite markers with those expected in pure specimens and in hybrids using assignment tests. The combined results led to the conclusion that the animal was a hybrid between a Scandinavian female wolf and a male dog. This finding confirms that inter-specific hybridization between wolves and dogs can occur in natural wolf populations. A possible correlation between hybridization and wolf population density and disturbance deserves further research.
Vilà & Wayne (1999): Hybridization between Wolves and Dogs. DOI: 10.1046/j.1523-1739.1999.97425.x.

Abstract
Concern has been expressed that European populations of gray wolves (Canis lupus) have extensively hybridized with domestic dogs (C. familiaris). We reviewed and analyzed surveys of mitochondrial and biparentally inherited genetic markers in dogs and wild populations of wolf‐like canids. Although dog‐wolf hybrids have been observed in the wild, significant introgression of dog markers into wild wolf populations has not yet occurred. Our investigation suggests that hybridization may not be an important conservation concern even in small, endangered wolf populations near human settlements. The behavioral and physiological differences between domestic dogs and gray wolves may be sufficiently great such that mating is unlikely and hybrid offspring rarely survive to reproduce in the wild.
Vilà et al. (1999): Mitochondrial DNA phylogeography and population history of the grey wolf Canis lupus. DOI: 10.1046/j.1365-294x.1999.00825.x.

Abstract
The grey wolf (Canis lupus) and coyote (C. latrans) are highly mobile carnivores that disperse over great distances in search of territories and mates. Previous genetic studies have shown little geographical structure in either species. However, population genetic structure is also influenced by past isolation events and population fluctuations during glacial periods. In this study, control region sequence data from a worldwide sample of grey wolves and a more limited sample of coyotes were analysed. The results suggest that fluctuating population sizes during the late Pleistocene have left a genetic signature on levels of variation in both species. Genealogical measures of nucleotide diversity suggest that historical population sizes were much larger in both species and grey wolves were more numerous than coyotes. Currently, about 300 000 wolves and 7 million coyotes exist. In grey wolves, genetic diversity is greater than that predicted from census population size, reflecting recent historical population declines. By contrast, nucleotide diversity in coyotes is smaller than that predicted by census population size, reflecting a recent population expansion following the extirpation of wolves from much of North America. Both species show little partitioning of haplotypes on continental or regional scales. However, a statistical parsimony analysis indicates local genetic structure that suggests recent restricted gene flow.
Vilà et al. (2003): Rescue of a severely bottlenecked wolf (Canis lupus) population by a single immigrant. DOI: 10.1098/rspb.2002.2184.

Abstract
The fragmentation of populations is an increasingly important problem in the conservation of endangered species. Under these conditions, rare migration events may have important effects for the rescue of small and inbred populations. However, the relevance of such migration events to genetically depauperate natural populations is not supported by empirical data. We show here that the genetic diversity of the severely bottlenecked and geographically isolated Scandinavian population of grey wolves (Canis lupus), founded by only two individuals, was recovered by the arrival of a single immigrant. Before the arrival of this immigrant, for several generations the population comprised only a single breeding pack, necessarily involving matings between close relatives and resulting in a subsequent decline in individual heterozygosity. With the arrival of just a single immigrant, there is evidence of increased heterozygosity, significant outbreeding (inbreeding avoidance), a rapid spread of new alleles and exponential population growth. Our results imply that even rare interpopulation migration can lead to the rescue and recovery of isolated and endangered natural populations.
vonHoldt et al. (2016): Whole-genome sequence analysis shows that two endemic species of North American wolf are admixtures of the coyote and gray wolf. DOI: 10.1126/sciadv.1501714.

Abstract
Protection of populations comprising admixed genomes is a challenge under the Endangered Species Act (ESA), which is regarded as the most powerful species protection legislation ever passed in the United States but lacks specific provisions for hybrids. The eastern wolf is a newly recognized wolf-like species that is highly admixed and inhabits the Great Lakes and eastern United States, a region previously thought to be included in the geographic range of only the gray wolf. The U.S. Fish and Wildlife Service has argued that the presence of the eastern wolf, rather than the gray wolf, in this area is grounds for removing ESA protection (delisting) from the gray wolf across its geographic range. In contrast, the red wolf from the southeastern United States was one of the first species protected under the ESA and was protected despite admixture with coyotes. We use whole-genome sequence data to demonstrate a lack of unique ancestry in eastern and red wolves that would not be expected if they represented long divergent North American lineages. These results suggest that arguments for delisting the gray wolf are not valid. Our findings demonstrate how a strict designation of a species under the ESA that does not consider admixture can threaten the protection of endangered entities. We argue for a more balanced approach that focuses on the ecological context of admixture and allows for evolutionary processes to potentially restore historical patterns of genetic variation.
vonHoldt et al. (2011): A genome-wide perspective on the evolutionary history of enigmatic wolf-like canids. DOI: 10.1101/gr.116301.110.

Abstract
High-throughput genotyping technologies developed for model species can potentially increase the resolution of demographic history and ancestry in wild relatives. We use a SNP genotyping microarray developed for the domestic dog to assay variation in over 48K loci in wolf-like species worldwide. Despite the high mobility of these large carnivores, we find distinct hierarchical population units within gray wolves and coyotes that correspond with geographic and ecologic differences among populations. Further, we test controversial theories about the ancestry of the Great Lakes wolf and red wolf using an analysis of haplotype blocks across all 38 canid autosomes. We find that these enigmatic canids are highly admixed varieties derived from gray wolves and coyotes, respectively. This divergent genomic history suggests that they do not have a shared recent ancestry as proposed by previous researchers. Interspecific hybridization, as well as the process of evolutionary divergence, may be responsible for the observed phenotypic distinction of both forms. Such admixture complicates decisions regarding endangered species restoration and protection.
Vonholdt et al. (2008): The genealogy and genetic viability of reintroduced Yellowstone grey wolves. DOI: 10.1111/j.1365-294X.2007.03468.x.

Abstract
The recovery of the grey wolf in Yellowstone National Park is an outstanding example of a successful reintroduction. A general question concerning reintroduction is the degree to which genetic variation has been preserved and the specific behavioural mechanisms that enhance the preservation of genetic diversity and reduce inbreeding. We have analysed 200 Yellowstone wolves, including all 31 founders, for variation in 26 microsatellite loci over the 10‐year reintroduction period (1995–2004). The population maintained high levels of variation (1995 H0 = 0.69; 2004 H0 = 0.73) with low levels of inbreeding (1995 FIS = –0.063; 2004 FIS = –0.051) and throughout, the population expanded rapidly (N1995 = 21; N2004 = 169). Pedigree‐based effective population size ratios did not vary appreciably over the duration of population expansion (1995 Ne/Ng = 0.29; 2000 Ne/Ng = 0.26; 2004 Ne/Ng = 0.33). We estimated kinship and found only two of 30 natural breeding pairs showed evidence of being related (average r = –0.026, SE = 0.03). We reconstructed the genealogy of 200 wolves based on genetic and field data and discovered that they avoid inbreeding through a wide variety of behavioural mechanisms including absolute avoidance of breeding with related pack members, male‐biased dispersal to packs where they breed with nonrelatives, and female‐biased subordinate breeding. We documented a greater diversity of such population assembly patterns in Yellowstone than previously observed in any other natural wolf population. Inbreeding avoidance is nearly absolute despite the high probability of within‐pack inbreeding opportunities and extensive interpack kinship ties between adjacent packs. Simulations showed that the Yellowstone population has levels of genetic variation similar to that of a population managed for high variation and low inbreeding, and greater than that expected for random breeding within packs or across the entire breeding pool. Although short‐term losses in variation seem minimal, future projections of the population at carrying capacity suggest significant inbreeding depression will occur without connectivity and migratory exchange with other populations.
Wayne & Shaffer (2016): Hybridization and endangered species protection in the molecular era. DOI: 10.1111/mec.13642.

Abstract
After decades of discussion, there is little consensus on the extent to which hybrids between endangered and nonendangered species should be protected by US law. As increasingly larger, genome‐scale data sets are developed, we can identify individuals and populations with even trace levels of genetic admixture, making the ‘hybrid problem’ all the more difficult. We developed a decision‐tree framework for evaluating hybrid protection, including both the processes that produced hybrids (human‐mediated or natural) and the ecological impact of hybrids on natural ecosystems. We then evaluated our decision tree for four case studies drawn from our own work and briefly discuss several other cases from the literature. Throughout, we highlight the management outcomes that our approach provides and the nuances of hybridization as a conservation problem.
Wilson et al. (2012): Y-chromosome evidence supports widespread signatures of three-species Canis hybridization in eastern North America.
DOI: 10.1002/ece3.301.

Abstract
There has been considerable discussion on the origin of the red wolf and eastern wolf and their evolution independent of the gray wolf. We analyzed mitochondrial DNA (mtDNA) and a Y‐chromosome intron sequence in combination with Y‐chromosome microsatellites from wolves and coyotes within the range of extensive wolf–coyote hybridization, that is, eastern North America. The detection of divergent Y‐chromosome haplotypes in the historic range of the eastern wolf is concordant with earlier mtDNA findings, and the absence of these haplotypes in western coyotes supports the existence of the North American evolved eastern wolf (Canis lycaon). Having haplotypes observed exclusively in eastern North America as a result of insufficient sampling in the historic range of the coyote or that these lineages subsequently went extinct in western geographies is unlikely given that eastern‐specific mtDNA and Y‐chromosome haplotypes represent lineages divergent from those observed in extant western coyotes. By combining Y‐chromosome and mtDNA distributional patterns, we identified hybrid genomes of eastern wolf, coyote, gray wolf, and potentially dog origin in Canis populations of central and eastern North America. The natural contemporary eastern Canis populations represent an important example of widespread introgression resulting in hybrid genomes across the original C. lycaon range that appears to be facilitated by the eastern wolf acting as a conduit for hybridization. Applying conventional taxonomic nomenclature and species‐based conservation initiatives, particularly in human‐modified landscapes, may be counterproductive to the effective management of these hybrids and fails to consider their evolutionary potential.
"Though this be madness, yet there is method in 't ..."

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SammysHP
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Re: Genetik der Wölfe: Hybridisierung, Introgression und Abstammungslinien

Beitrag von SammysHP »

Danke, schöne Sammlung! Ein paar Veröffentlichungen habe ich beim Überfliegen bereits wiedererkannt. Bleibt trotzdem noch genug für die langen Winternächte.

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Dr_R.Goatcabin
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Re: Genetik der Wölfe: Hybridisierung, Introgression und Abstammungslinien

Beitrag von Dr_R.Goatcabin »

Dann erfüllt das gelgentliche Ablegen von DOIs in meine Schublade ja doch einen Zweck. - Ich stelle mir gerne vor, dass wenigstens mal die eine hotte Bachelorette süß schnieft, ihr hier Such- und Sortierarbeit abgenommen wurde, sie sich ergo früher auf ihr Motivationsschreiben für den konsekutiven Master konzentrieren kann, und ich werde wieder froh. ^^

Viele der Publikationen referenzieren freilich munter untereinander, aber in den einsamen Winternächten bleibt trotzdem genügend Spiel, solche Listen zu erweitern; je nachdem, welcher Frage gezielter nachgegangen werden soll. Das wird hier dann schnell echt unübersichtlich.
"Though this be madness, yet there is method in 't ..."

Schattenwolf

Re: Genetik der Wölfe: Hybridisierung, Introgression und Abstammungslinien

Beitrag von Schattenwolf »

Danke...mal was seriöses zum Thema. :) Nicht einfach so dahinger..... ;)

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Re: Genetik der Wölfe: Hybridisierung, Introgression und Abstammungslinien

Beitrag von Wolfs-Theoretiker »

Hallo Dr_R.G.

danke für die tollen wissenschaftlichen Arbeiten. Da kann man wirklich drauf zurückgreifen.

Wobei ich mich natürlich nur für die Wölfe aus dem Stammbaum der ZEP interessiere.
Ja der Hindrikson hat da allerhand zu bieten.

Grüsse, WT
"Die Natur betrügt uns nie. Wir sind es immer, die wir uns selbst betrügen." Jean-Jacques Rousseau

Schattenwolf

Re: Genetik der Wölfe: Hybridisierung, Introgression und Abstammungslinien

Beitrag von Schattenwolf »

Hallo W-T.

danke für dein Interesse an der Zentraleuropäischen Flachlandpopulation von Canis lupus.

Viele Grüße, SW
PS: Dann kann der Hybridenschwarm Thread ja nun geschlossen oder gelöscht werden?

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Dr_R.Goatcabin
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Re: Genetik der Wölfe: Hybridisierung, Introgression und Abstammungslinien

Beitrag von Dr_R.Goatcabin »

Für besonders determinierte Forscher: Buchteil in Gompper (2014): Free-ranging dogs and wildlife conservation. Oxford University Press, 312 S. ISBN: 978-0-19-966321-7.

Leonard et al. (2013): Impact of hybridization with domestic dogs on the conservation of wild canids.
This chapter discusses the effects of hybridization with domestic dogs on the conservation of wild canids. Hybridization between gray wolves and dogs are the majority of the documented hybridization between wild and domestic canids, and it does not usually threaten breeding opportunities. The chapter states that hybridization between dogs and rarer wild species can reduce its effective number of breeders, contributing to its genetic diversity erosion.

Lepczyk (2015):Book Review. DOI: 10.1002/jwmg.934.

(Google Übersetzung)
Der beste Freund des Mannes. Diese 3 Wörter sind vielleicht die gebräuchlichste Art, wie wir uns auf Hunde und unsere Beziehung zu ihnen beziehen. Aber Hunde sind sicherlich viel mehr als nur Freunde oder Gefährten, sie sind Teil der menschlichen Gesellschaft sowie vieler Ökosysteme der Welt. Tatsächlich investieren wir an vielen Orten auf der Welt Millionen von Dollar in ihre Fürsorge, ihr Überleben und ihre Freude. Im Gegenzug leisten Hunde eine Reihe wichtiger Aufgaben für die Menschen, von der Viehhaltung bis zur Entdeckung invasiver Arten und vielleicht am wichtigsten Sie sind integraler Bestandteil vieler Familien und Gemeinschaften. Obwohl Hunde seit Jahrtausenden Teil menschlicher Gesellschaften sind und wir sie für viele ausdrückliche Zwecke selektiv gezüchtet haben, wurden sie von seriösen ökologischen Forschungen weitgehend vernachlässigt. Wie FreeRanging Dogs and Wildlife Conservation hervorhebt, ist unser Wissen über die ökologische Rolle von Hunden und die vielfältigen Wechselwirkungen mit anderen Arten und dem Ökosystem in der Tat rudimentär.

Die von Matthew Gompper herausgegebene Ausgabe von "Free-Ranging Dogs and Wildlife Conservation" enthält eine kurze Einführung und ein Dutzend Kapitel führender Experten, die von grundlegenden ökologischen Fragen im Zusammenhang mit Hunden bis hin zu Management- und Naturschutzfragen reichen. Das Buch fesselt den Leser zunächst mit einem fesselnden Vorwort über die Wiederentdeckung des Schwarzfußfrettchens (Mustela nigripes), das als ausgestorben galt, bis man 1981 in Wyoming von einem freilaufenden Hund getötet wurde Die verbleibende Frettchenpopulation wurde entdeckt und befindet sich seitdem auf dem Weg der Besserung. Daher zeigt die Situation sowohl die positiven als auch die negativen ökologischen Auswirkungen, die Hunde in der Natur haben können, vom Naturschutzretter bis zum subventionierten invasiven Raubtier. Ab diesem Zeitpunkt werden in dem Buch beide Elemente konsequent umrissen, was den Ökologen klar macht, dass Artenwechselwirkungen komplex und mit Kompromissen behaftet sind.

Im Anschluss an das Vorwort erläutert Gompper in einer kurzen Einführung die grundlegende Konzeptualisierung des Buches und erläutert anschaulich, wie Menschen Hunde sehen und wie Wildtiere Hunde sehen können und wie wichtig es ist, die Ökologie frei lebender Hunde zu verstehen. Von hier aus geht das Buch mit einem umfassenden Überblick über die Literatur im ersten Kapitel in die nächste Runde. In zahlreichen Veröffentlichungen erfahren wir, wie der Hund der häufigste Fleischfresser der Welt ist, der freilaufende Hunde besitzt und wie Hunde, Menschen und wild lebende Tiere eine komplexe Beziehung zueinander eingehen. In der Tat folgt dieses erste Kapitel sehr stark der Ader eines schönen synthetischen Artikels, den man in BioScience oder Frontiers in Ecology and the Environment als eigenständige Rezension lesen würde.

In den folgenden Kapiteln werden im Verlauf des Buches viel spezifischere Themen behandelt, wobei die meisten verschiedene Formen der ökologischen Interaktion zum Gegenstand haben. So lernen wir im zweiten Kapitel, wie Hunde als Raubtiere agieren und welche möglichen Einflüsse sie auf das Ökosystem haben, und zwar über die daraus resultierende trophische Dynamik. Es ist nicht überraschend, dass Hunde tatsächlich andere Wildtiere töten, aber das Ausmaß, in dem dies die trophische Dynamik des Systems beeinflussen kann, ist weiterhin wenig bekannt. Aus dieser Perspektive auf Ökosystemebene gehen wir zum dritten Kapitel über, in dem verschiedene Formen des Wettbewerbs dargestellt werden, in denen Hunde mit anderen Fleischfressern konkurrieren. Das Studium von Wettbewerben ist bekanntermaßen schwierig, und wie dieses Kapitel zeigt, müssen wir noch viel darüber lernen, inwiefern freilaufende Hunde mit anderen Fleischfressern konkurrieren können. Das vierte Kapitel befasst sich mit der Verhaltensökologie anderer Wildtiere als Reaktion auf die Anwesenheit von Hunden. So wirken Hunde als Störer. In Kapitel 4 geht es insbesondere darum, wie wild lebende Tiere auf das Vorhandensein von Hunden reagieren. Dies ist angesichts der wachsenden Literatur von zentraler Bedeutung, die die Auswirkungen neuartiger Raubtiere auf die Demografie von Beutetieren zeigt.

In einer Art Richtungsumkehr kehrt das fünfte Kapitel zur Idee der Raubtierjagd zurück, diesmal jedoch mit dem Schwerpunkt auf der Ausbeutung von Hunden. Wie das Kapitel hervorhebt, sind Hunde nicht einfach Konkurrenten oder Raubtiere, sondern tatsächlich Beute für andere Fleischfresser. Obwohl das Kapitel die Ergebnisse einer Internet-Literaturrecherche hervorhebt, schien es den Punkt zu verfehlen, wie viele Hunde letztendlich bei der Jagd auf Wildarten wie Bären und Schweine getötet werden. Kapitel 6 ist ein gelungenes Kapitel über Hunde und Krankheiten. Obwohl wir sehr viel über die Arten von Krankheiten wissen, die Hunde infizieren und die sie übertragen, müssen wir noch viel darüber lernen, wie sich Krankheiten zwischen Hunden und Wildtieren bewegen und welche ökologischen Folgen solche Bewegungen haben. Kapitel 7 ist ebenfalls ein wichtiges Kapitel in Bezug auf die grundlegende Ökologie, das Management und die Erhaltung, da es sich mit der Hybridisierung zwischen Haushunden und Wildkaniden befasst. Obwohl die absichtliche Hybridisierung für solche Erfolgsgeschichten im Naturschutz wie den Florida-Panther (Puma concolor coryi) als ziemlich wertvoll angesehen wurde, ist die meiste Hybridisierung zwischen Arten unbeabsichtigt und führt zu einer weiteren Schädigung seltener oder gefährdeter Arten, wie sie beispielsweise zwischen hawaiianischen Enten vorkommen ( koloa (Anas wyvilliana) und Stockenten (Anas platyrhynchos). Das Kapitel hebt die Vielfalt der Arten hervor, in denen Haushunde bekanntermaßen mit wilden Caniden hybridisieren, und welche Auswirkungen dies auf die Erhaltung hat. Kapitel 8 folgt insofern, als es sich auf die populationsgenetische Struktur von Hunden konzentriert. Obwohl wir uns weniger mit aktuellen ökologischen Wechselwirkungen befassen als in den vorangegangenen Kapiteln, zeigt das Kapitel deutlich, wie unterschiedlich Haushunde auf der ganzen Welt sind.

Das letzte Drittel des Buches, das mit Kapitel 9 beginnt, konzentriert sich mehr auf die Rolle von Hunden bei der Erhaltung und Bewirtschaftung. Kapitel 9 befasst sich speziell mit der Art und Weise, wie Hunde eingesetzt werden können, um Schutzkonflikte zu verringern, beispielsweise zwischen Landwirten und Raubtieren. Darüber hinaus vermittelt das Kapitel den steigenden Wert von Hunden bei der Vermittlung von Konflikten, wie aktuelle Wirtschaftsstudien belegen. Aufbauend auf dieser Rolle beim Schutz wird in Kapitel 10 der Einsatz von Spürhunden behandelt. In diesem Kapitel werden insbesondere die Eigenschaften beschrieben, die Hunde zu guten Erkennungshunden machen, sowie eine Reihe von Beispielen, in denen sich Hunde als wirksam bei der Identifizierung von Arten erwiesen haben, die (sowohl einheimische als auch invasive) Schutzbedenken haben. Obwohl solche Schutzhunde mit realen Kosten verbunden sind, wird im Kapitel hervorgehoben, wie sie mit anderen Methoden zur Artenerkennung verglichen werden. Das vorletzte Kapitel (Kapitel 11) geht direkt von der Erhaltung zum Einsatz von Hunden in der Jagd über. Obwohl dies in den Kapiteln etwas einzigartig ist, ist es sehr wertvoll, die Rolle zu diskutieren, die Hunde bei der Jagd spielen, da sie während ihrer Feldzeit sowohl Beute als auch anderen Arten begegnen. Darüber hinaus bietet die einfache Mitnahme von Hunden bei der Jagd neuen Arten die Möglichkeit, in ein Ökosystem einzudringen, das möglicherweise mit dem Fell des Hundes verbunden ist (z. B. Arthropoden wie Zecken, Flöhe und Läuse). Solche Punkte sind eine Überlegung wert. Das letzte Kapitel des Buches (Kapitel 12) befasste sich mit den menschlichen Dimensionen von Hund-Tier-Interaktionen. Wie die erfahrensten Wildtierökologen wissen, erfordert der Schlüssel für ein erfolgreiches Management häufig die Zustimmung der Beteiligten. Gleiches gilt für das Management von freilaufenden Hunden, insbesondere, wenn mehr Menschen Hunde besitzen.

Insgesamt ist das Buch inhaltlich und strukturell gut angelegt und eignet sich sowohl zum Herausziehen einzelner Kapitel als auch als Anlaufstelle für Recherchehilfen. Ein Element des Buches, das wirklich zu jedem Kapitel beiträgt, sind die kleinen Beschriftungsfelder, die kurze Fallstudien enthalten, die Terminologie verdeutlichen oder kurze Anekdoten von Relevanz enthalten. Obwohl einige dieser Felder Informationen enthalten, die an anderer Stelle im Buch zu finden sind, z. B. Diskussionen über Dingos (Canis lupus dingo), tragen viele erheblich zum Thema des Kapitels bei. Ein weiteres Element des Buches, das eine große Bereicherung darstellt, ist die umfangreiche Zusammenstellung von Referenzen. Viele der Kapitel werden ausführlich zitiert, sodass jeder, der mehr lernen oder seine eigene Forschung entwerfen möchte, eine reichhaltige Quelle zur Hand hat. Schließlich sind die Kapitel selbst gut editiert und im Allgemeinen von Autor zu Autor leicht zu lesen, was bei editierten Bänden nicht immer der Fall ist.

Einige Kritikpunkte befassen sich jedoch mit der kapitelübergreifenden Replikation von Material und bestimmten Stilelementen. Im Falle einer Replikation ist es schwierig, den Autoren einen vollständigen Vorwurf zu machen, da nur eine begrenzte Anzahl wichtiger Beispiele hervorgehoben werden muss und es sinnvoll ist, einige Informationen zu wiederholen. Da viele Leser wahrscheinlich nur ein oder mehrere Kapitel in einer Sitzung lesen, ist diese Replikation möglicherweise keine Ablenkung, sondern tatsächlich erforderlich. Was die stilistischen Aspekte angeht, hätte ich mich wirklich über eine konsequente Darstellung der erforderlichen Forschungsagenda für freiberufliche Hunde gefreut. Die meisten Kapitel erforderten mehr Nachforschungen und einige sehr detaillierte Schritte. Ein einheitlicher Abschnitt für den Forschungsbedarf in jedem Kapitel oder ein abschließendes Kapitel, in dem die Prioritäten und die nächsten Schritte in Forschung und Erhaltung festgelegt werden, haben jedoch möglicherweise alle Themen miteinander verknüpft. Diese Themen sind eher ein Trottel als große Kritikpunkte und sollten keine interessierten Kreise davon abhalten, das Buch zu lesen oder zu kaufen.

Letztendlich ist "Free-ranging dogs and wildlife conservation" ein wertvolles Buch sowohl für Laien als auch für professionelle Wissenschaftler. Es ist ein reiches Buch und füllt eine große Lücke in unserem Wissen. Ich gehe daher davon aus, dass dieses Buch in 10 Jahren als wegweisende Veröffentlichung angesehen wird, die als Leitfaden für viele neue Forschungspfade und Erhaltungsmaßnahmen dient.
"Though this be madness, yet there is method in 't ..."

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Dr_R.Goatcabin
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Re: Genetik der Wölfe: Hybridisierung, Introgression und Abstammungslinien

Beitrag von Dr_R.Goatcabin »

de Groot et al. (2016): Decades of population genetic research reveal the need for harmonization of molecular markers: the grey wolf Canis lupus as a case study: Harmonization of genetic markers in wolves. DOI: 10.1111/mam.12052. Volltext Google Translation

Abstract
Nach den seit den 1970er Jahren umgesetzten Schutzmaßnahmen nimmt die Zahl der großen Fleischfresser zu und sie kehren in Gebiete zurück, in denen sie jahrzehntelang oder sogar jahrhundertelang abwesend waren. Überwachungsprogramme für diese Arten stützen sich weitgehend auf nichtinvasive Probenahme und Genotypisierung. Versuche, die Ergebnisse solcher Studien auf einer größeren räumlichen oder zeitlichen Ebene miteinander zu verknüpfen, leiden jedoch häufig unter der Inkompatibilität genetischer Marker, die von Forschern in verschiedenen Labors implementiert wurden. Dies ist besonders wichtig für Dispersionsgeräte für große Entfernungen, da hier harmonisierte Überwachungsschemata erforderlich sind, die das Verständnis des Genflusses und der Ausbreitungsdynamik ermöglichen.

Basierend auf einem Überblick über genetische Studien zu Graue Wölfe C anis lupus aus Europa geben wir einen Überblick über die derzeit verwendeten genetischen Marker und identifizieren Möglichkeiten und Hürden für Studien auf der Grundlage von Datensätzen auf Kontinentebene.

Unsere Ergebnisse unterstreichen die dringende Notwendigkeit einer Harmonisierung der Methoden, um grenzüberschreitende Forschung auf der Grundlage bereits erhobener Daten zu ermöglichen und diese Daten mit künftig erhobenem Material zu verknüpfen. Wir schlagen eine rechtzeitige Standardisierung neu entwickelter Genotypisierungsansätze vor und schlagen vor, dass Maßnahmen auf die Einrichtung gemeinsamer Einzelnukleotid-Polymorphismus-Panels, die Sequenzierung von Mikrosatelliten der nächsten Generation, eine gemeinsame Referenzprobensammlung und eine Online-Datenbank für den Datenaustausch abzielen.

Eine verstärkte Zusammenarbeit zwischen Genforschern, die sich mit großen Fleischfressern in Konsortien befassen, würde eine Straffung der Methoden, ihre schnellere und umfassendere Anwendung und die Erzielung von Ergebnissen auf den großen räumlichen Skalen ermöglichen, die letztendlich für die Erhaltung dieser charismatischen Art von Bedeutung sind.
"Though this be madness, yet there is method in 't ..."

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Re: Genetik der Wölfe: Hybridisierung, Introgression und Abstammungslinien

Beitrag von Erklärbär »

Molecular Ecology
Volume 27, Issue 18

On the path to extinction: Inbreeding and admixture in a declining grey wolf population


Daniel Gómez‐Sánchez 
Iñigo Olalde 
Natalia Sastre

First published: 03 August 2018

https://doi.org/10.1111/mec.14824

Abstract

Allee effects reduce the viability of small populations in many different ways, which act synergistically to lead populations towards extinction vortexes. The Sierra Morena wolf population, isolated in the south of the Iberian Peninsula and composed of just one or few packs for decades, represents a good example of how diverse threats act additively in very small populations. We sequenced the genome of one of the last wolves identified (and road‐killed) in Sierra Morena and that of another wolf in the Iberian Wolf Captive Breeding Program and compared them with other wolf and dog genomes from around the world (including two previously published genome sequences from northern Iberian wolves). The results showed relatively low overall genetic diversity in Iberian wolves, but diverse population histories including past introgression of dog genes. The Sierra Morena wolf had an extraordinarily high level of inbreeding and long runs of homozygosity, resulting from the long isolation. In addition, about one‐third of the genome was of dog origin. Despite the introgression of dog genes, heterozygosity remained low because of continued inbreeding after several hybridization events. The results thus illustrate the case of a small and isolated wolf population where the low population density may have favoured hybridization and introgression of dog alleles, but continued inbreeding may have resulted in large chromosomal fragments of wolf origin completely disappearing from the population, and being replaced by chromosomal fragments of dog origin. The latest population surveys suggest that this population may have gone extinct.
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