Did domestic pigs that escaped after the Fukushima Daiichi nuclear power plant accident cause genetic contamination of the wild boar population?
The 2011 Tohoku earthquake drastically changed human activities in parts of Fukushima Prefecture, Japan. The subsequent tsunami damage and radioactive fallout from the Fukushima Daiichi nuclear power plant resulted in the abandonment of agricultural land and towns, allowing the expansion of wild mammal populations into areas previously inhabited by their domesticated relatives. This study examined possible hybridisation between wild boars and domesticated pigs in Fukushima. We analysed the mitochondrial DNA sequences of 75 wild boars collected from Fukushima populations between 2014 and 2016. While 71 boars had Asian boar haplotypes, four boars identified as wild boars phenotypically had mitochondrial genomes extremely close to that of European domesticated pigs, implying ongoing genetic contamination of wild boar populations from feral domesticated pigs. This suggests the need for detailed genetic monitoring using nuclear DNA markers and population management based on genetic data.