1 Evolutionary dynamics of bovine coronaviruses: Natural selection 1 pattern of the spike gene implies adaptive evolution of the strains 2 3 running title: Evolution of Betacoronavirus1 4 5 Contents: Title page (P:1), ABSTRACT (P:2), INTRODUCTION (P:3), RESULTS (P:6), 6 DISCUSSION (P:12), MATERIALS AND METHODS (P:18), ACKNOWLDGEMENTS 7 (P:23), REFERENCES (P:24) and LEGENDS OF FIGURES (P:34) 8 9 Mehdi R M Bidokhti1†, Madeleine Tråvén1, Neel K Krishna2, Muhammad Munir3,4, 10 Sándor Belák3,4, Stefan Alenius1, Martí Cortey5 11 12 1Division of Ruminant Medicine and Veterinary Epidemiology, Department of Clinical Sciences, 13 Swedish University of Agricultural Sciences, Box 7054, SE-750 07 Uppsala, Sweden 14 2Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, 700 15 West Olney Road, Norfolk, Virginia 23507-1696, USA 16 3Department of Virology, Immunobiology and Parasitology, National Veterinary Institute, Box 17 7028, SE-751 89 Uppsala, Sweden 18 4Department of Biomedical Sciences and Veterinary Public Health , Swedish University of 19 Agricultural Sciences, SE-750 07 Uppsala, Sweden 20 5Department of Immunology, The Pirbright Institute, Ash Road, Pirbright GU24 0NF, United 21 Kingdom 22 23 † Corresponding author. E-mail: