Figure 2  Phylogenetic tree of novel betacoronaviruses based on the deduced amino acid sequence of spike protein. SARS, severe acute respiratory syndrome; CoV, coronavirus; HCoV, human CoV; BtCoV, bat CoV; BWCoV, beluga whale CoV; IBV, avian infectious bronchitis. Scale bar indicates genetic distance estimated by using WAG+G+I+F model implemented in MEGA5 (www.megasoftware.net).