The DNA of wild boars in North-West Europe is being increasingly 'contaminated' by genes from domesticated pigs.
Resource nr. 13, February 28, 2013
This is reported by the Resource Ecology Group which has compared the DNA of wild boars with that of domestic pigs. Researcher Daniel Goedbloed examined the DNA of 88 wild boars in the Netherlands, Germany and Luxembourg for the presence of genetic information from the domestic pig. Ten percent of the wild boars had DNA fragments from the domestic pig in their genomes, he reports in this month's Molecular Ecology. This infiltration by domestic pig genes has happened in the past ten years.
That this can happen is surprising, says fellow researcher Pim van Hooft. 'The Dutch pig population is kept in enclosures and has no contact with wild boars in the forests. We have no proof that domestic pigs have escaped from farms.' Van Hooft suspects that the DNA mixing has taken place on farms where wild boar are being raised for meat consumption. These wild boars are often crossed with domestic pigs to increase the brood size and growth rate. He suspects that some of them have escaped or have been set free from these farms, allowing them to mate with their wild relatives in the forest.
How this mixing of pig-DNA has affected the wild boar population is a question for further research. It is possible that the DNA mixing will increase the reproduction rate among wild boars, as domestic pigs produce more young than wild ones, says Van Hooft. In addition, resistance to diseases in the wild boar population could go down. This is because domesticated pigs are protected against infections, which lowers the selection pressure for disease resistance.
Resource Ecology discovered the DNA mixing by accident. The group is studying the genetic diversity and disease spread among wild boars, research financed by the Royal Dutch Hunting Association.