1. Center for Animal Biotechnology and Genomics (G.S., K.A.D., J.K., D.W.B., T.E.S., R.C.B., G.A.J., F.W.B.), Texas A&M University, College Station, Texas 77843
2. Department of Veterinary Integrative Biosciences (K.A.D., D.W.B., R.C.B., G.A.J.), Texas A&M University, College Station, Texas 77843
3. Department of Animal Science (G.S., J.K., T.E.S., F.W.B.), Texas A&M University, College Station, Texas 77843
4. Department of Physiology (G.F.W.), The University of Western Ontario, London, Ontario, Canada N6A 5C1