Abstract
1 Centre for Infectious Diseases, Royal (Dick) School of Veterinary Medicine, Chancellor's Building, University of Edinburgh, Edinburgh EH16 4SB, UK
2 Biomedical Research Group, Department of Biosciences, University of Kent, Kent CT2 7NJ, UK
3 Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden
4 Department of Genome Sciences, University of Washington, 1705 NE Pacific, Seattle, WA 98195, USA