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

Authors

Timothy J. Smyser, USDA APHIS Wildlife ServicesFollow
Michael A. Tabak, USDAFollow
Chris Slootmaker, USDA National Wildlife Research Center
Michael S. Robeson II, University of Arkansas for Medical Sciences
Ryan S. Miller, USDA APHISFollow
Mirte Bosse, Wageningen University
Hendrik-Jan Megens, Wageningen University
Martien A.M. Groenen, Wageningen University
Samuel Rezende Paiva, Embrapa Recursos Genéticos e Biotecnologia, Brasília
Danielle Assis de Faria, Universidade de Brasília
Harvey D. Blackburn, USDA ARSFollow
Brandon S. Schmit, USDA-APHIS-Wildlife Services’ National Wildlife Disease ProgramFollow
Antoinette J. Piaggio, USDA APHIS Wildlife ServicesFollow

ORCID IDs

Timothy J. Smyser https://orcid.org/0000-0003-4542-3077

Michael A. Tabak https://orcid.org/0000-0002-2986-7885

Michael S. Robeson II https://orcid.org/0000-0001-7119-6301

Harvey D. Blackburn https://orcid.org/0000-0003-0575-1594

Document Type

Article

Date of this Version

2020

Citation

Molecular Ecology. 2020;29:1103–1119.

DOI: 10.1111/mec.15392

Comments

US govt

Abstract

Invasive alien species are a significant threat to both economic and ecological systems. Identifying the processes that give rise to invasive populations is essential for implementing effective control strategies. We conducted an ancestry analysis of invasive feral swine (Sus scrofa, Linnaeus, 1758), a highly destructive ungulate that is widely distributed throughout the contiguous United States, to describe introduction pathways, sources of newly emergent populations and processes contributing to an ongoing invasion. Comparisons of high-density single nucleotide polymorphism genotypes for 6,566 invasive feral swine to a comprehensive reference set of S. scrofa revealed that the vast majority of feral swine were of mixed ancestry, with dominant genetic associations to Western heritage breeds of domestic pig and European populations of wild boar. Further, the rapid expansion of invasive feral swine over the past 30 years was attributable to secondary introductions from established populations of admixed ancestry as opposed to direct introductions of domestic breeds or wild boar. Spatially widespread genetic associations of invasive feral swine to European wild boar deviated strongly from historical S. scrofa introduction pressure, which was largely restricted to domestic pigs with infrequent, localized wild boar releases. The deviation between historical introduction pressure and contemporary genetic ancestry suggests wild boar-hybridization may contribute to differential fitness in the environment and heightened invasive potential for individuals of admixed domestic pig–wild boar ancestry.