Reintroductions and genetic introgression from domestic pigs have shaped the genetic population structure of Northwest European wild boar

Abstract

BackgroundPopulation genetic studies focus on natural dispersal and isolation by landscape barriers as the main drivers of genetic population structure. However, anthropogenic factors such as reintroductions, translocations and wild x domestic hybridization may also have strong effects on genetic population structure. In this study we genotyped 351 Single Nucleotide Polymorphism markers evenly spread across the genome in 645 wild boar (Sus scrofa) from Northwest Europe to evaluate determinants of genetic population structure.ResultsWe show that wild boar genetic population structure is influenced by historical reintroductions and by genetic introgression from domestic pigs. Six genetically distinct and geographically coherent wild boar clusters were identified in the Netherlands and Western Germany. The Dutch Veluwe cluster is known to be reintroduced, and three adjacent Dutch and German clusters are suspected to be a result of reintroduction, based on clustering results, low levels of heterozygosity and relatively high genetic distances to nearby populations. Recent wild x domestic hybrids were found geographically widespread across clusters and at low frequencies (average 3.9%). The relationship between pairwise kinship coefficients and geographic distance showed male-biased dispersal at the population genetic level.ConclusionsOur results demonstrate that wildlife and landscape management by humans are shaping the genetic diversity of an iconic wildlife species. Historical reintroductions, translocation and recent restocking activities with farmed wild boar have all influenced wild boar genetic population structure. The current trend of wild boar population growth and range expansion has recently led to a number of contact zones between clusters, and further admixture between the different wild boar clusters is to be expected.

Mixed ancestry from wild and domestic lineages contributes to the rapid expansion of invasive feral swine

“…Furthermore, increases in wild boar ancestry among newly emergent feral swine populations could result from the intensification of environmental selective pressures if the fitness advantages of individuals with wild boar phenotypic attributes become greater as limiting factors, such as winter severity, become more restrictive with northward and inland range expansion (McClure et al, 2015; Snow et al, 2017). Support for the assertion that domestic pig–wild boar hybrids may be highly invasive can be drawn from the observed introgression of domestic pigs into native European wild boar populations and subsequent proliferation of admixed genotypes among wild populations in Europe (Fulgione et al, 2016; Goedbloed, Hooft, et al, 2013; Goedbloed, Megens, et al, 2013). Intensive artificial selection imposed during the domestication process has served to dramatically increase the fecundity of domestic pigs relative to wild boar (Miller, 2017).…”

High domestic pig contribution to the local gene pool of free-living European wild boar: a case study in Poland

“…In addition, mtDNA sequencing, microsatellite genotyping, and a single-nucleotide polymorphism (SNP) assay have been used to look for evidence of introgression (Giuffra et al 2000;Scandura et al 2008, 2011b, Frantz et al 2012, 2013, Goedbloed et al 2013bHerreroMedrano et al 2013;Iacolina et al 2016b).…”

A common garden design reveals population‐specific variability in potential impacts of hybridization between populations of farmed and wild Atlantic salmon, Salmo salar L.

“…; Goedbloed et al. ). Within agriculture and forestry, studies on hybridization generally focus on crop–wild interactions and have provided valuable insights into how genetic changes within wild populations impact local plant population resilience and transgenic crop risk assessments (Adler et al.…”