Genomic consequences of a century of inbreeding and isolation in the Danish wild boar population

Demographic events such as series of bottlenecks impact the genetic
variation and adaptive potential of populations. European megafauna, such
as wild boars (Sus scrofa), have experienced severe climatic and size
fluctuations that have shaped their genetic variation. Habitat
fragmentation as well as human-mediated translocations have further
contributed to the complex demographic history of European wild boar.
Danish wild boars represent an extreme case of a small and isolated
population founded by four wild boars from Germany. Here, we explore the
genetic composition of the Danish wild boar population in Klelund. We
genotyped all 21 Danish wild boars that were recently transferred from the
source population in Lille Vildmose into the Klelund Plantation to
establish a novel wild boar population. We compared the Danish wild boars
to high‐density single nucleotide polymorphism genotypes from a
comprehensive reference set of 1263 wild and domesticated pigs, including
11 individuals from Ulm, one of two presumed founder locations in Germany.
Our findings support the European wild background of the Danish population
and no traces of gene flow with wild or domesticated pigs were found. The
narrow genetic origin of the Danish wild boars is illustrated by extremely
long and frequent runs of homozygous stretches in their genomes,
indicative of recent inbreeding. This study provides the first insights
into one of the most inbred wild boar populations globally established a
century ago from a narrow base of only four founders. --