Genetic Relationships of Feral Pigs (Sus scrofa) in North America: Progress Report, Spring 2009

McCann, Blake; Simmons, Rebecca; Sweitzer, Richard

Preliminary Results for MtDNA. Abstract: Pigs (Sus scrofa) are native to parts of Europe, Asia, and Africa, but they have been repeatedly introduced to new geographic locations throughout the world. Because pigs are such successful invaders and capable competitors with native species their presence is generally viewed as ecologically detrimental. Additional damages are manifested in economic losses for repair or replacement of properties and the cost of control or eradication programs. In North America, management efforts would benefit from a better understanding of the phylogeography and population biology of feral pigs. Here we investigate the utility of a ~600 base pair segment of the MtDNA D-loop for determining the genetic relatedness of feral pig populations on a national scale, and for identifying source populations for feral pigs occupying new ranges. To accomplish this we obtained 428 tissue samples from feral pigs in 25 U.S. states. From this sample we examined a subset of 55 animals, representing all 25 states. Using maximum parsimony, maximum likelihood, and Bayesian methods, and network analysis approaches, we identified 26 haplotypes and constructed trees and networks describing feral pig relatedness. Maximum divergence between haplotypes had an uncorrected “p” distance of 0.00-3.57, which provided useful information for phylogenies. However, we could not draw many definitive conclusions, though some population and geographic relationships were apparent. Perhaps additional relationships could be elucidated with a larger sample size, including more locations within states. Moreover, we believe that this MtDNA marker will be most valuable for establishing a basis to exploit additional, more quickly evolving markers. We are encouraged by the results of this preliminary study and are optimistic about the potential of this research to provide useful information to managers dealing with the damaging effects of this invasive species.