Introgression dynamics from invasive pigs into wild boar following the March 2011 natural and anthropogenic disasters at Fukushima

Abstract

Natural and anthropogenic disasters have the capability to cause sudden extrinsic environmental changes and long-lasting perturbations including invasive species, species expansion and influence evolution as selective pressures force adaption. Such disasters occurred on 11 March 2011, in Fukushima, Japan, when an earthquake, tsunami and meltdown of a nuclear power plant all drastically reformed anthropogenic land use. Using genetic data, we demonstrate how wild boar ( Sus scrofa leucomystax ) have persevered against these environmental changes, including an invasion of escaped domestic pigs ( Sus scrofa domesticus ). Concurrently, we show evidence of successful hybridization between pigs and native wild boar in this area; however in future offspring, the pig legacy has been diluted through time. We speculate that the range expansion dynamics inhibit long-term introgression and introgressed alleles will continue to decrease at each generation while only maternally inherited organelles will persist. Using the gene flow data among wild boar, we assume that offspring from hybrid lineages will continue dispersal north at low frequencies as climates warm. We conclude that future risks for wild boar in this area include intraspecies competition, revitalization of human-related disruptions and disease outbreaks.

Assessing population structure and migration patterns of wild boar (Sus scrofa) in Japan

“…Moreover, it is feasible for wild boar and domestic pigs to interbreed. In fact, the presence of hybrids has been reported in Japan 4 , 34 , 35 . Thus, when farms have inadequate biosecurity, there is a risk that infectious diseases might also be easily transmitted.…”

Genetic Contributions of Genes on Sex Chromosomes and Mitochondrial DNA in a Pedigreed Population

“…On the other hand, introduction of external genes to increase genetic variance could have risk of genetic contamination or pollution of a population (e.g., [40][41][42]). Genetic pollution is also a problem in managing the genetic diversity of wild animal populations, such as the case of wild boars in Japan reported after the Fukushima Daiichi Nuclear Power Plant accident in 2011 (e.g., [42][43][44]). Thus, providing a proper methodology to manage the genetic composition in a target population is always essential.…”