The Role of the Environment in Shaping the Genomic Variation in an Insular Wild Boar Population

Abstract

The Sardinian population of wild boar (WB, Sus scrofa meridionalis) has evolved on this Mediterranean island since its arrival in Neolithic age. Climate and land use vary across the island; high temperatures and dryness represent limiting factors for the development and reproduction of the species. Hence, the environment can have contributed to create the morphological differences we observe today across the island and could sustain the genetic structure that has been previously observed using neutral molecular markers. We therefore searched for genomic signatures of local adaptation in a sample of Sardinian WB genotyped at almost 50 K single nucleotide polymorphisms (SNPs). Genetic structure was observed in the population separating the northwest and southwest from the east of the island, where internal substructure also emerged. We identified 49 SNPs as candidate loci involved in adaptation and 61 genes. Gene ontology enrichment analysis revealed over-representation of terms related to cell localization, motility, and adhesion, but also related to anatomical development and immunity. According to our results, the environment seems to have played a role in shaping the genetic differentiation of the Sardinian wild boar in a limited evolutionary timescale.