1. Canadian Centre for Swine Improvement Inc., Central Experimental Farm, Building #75, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada
2. Department of Animal Biosciences, University of Guelph, Guelph, ON N1G 2W1, Canada
3. Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
4. Alliance Genetics Canada Inc. PO Box 24039, Edward RPO, 107 Edward Street, St. Thomas, ON N5P 1Y0, Canada