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.