Phylogenetic relationships based on a 440-nt sequence in a conserved region of gene 1b of Rocky Mountain bat coronaviruses (RM-Bt-CoVs) (shown in boldface), group 1 coronaviruses of Asian bats (BtCoVs), and human coronaviruses 229E and NL63. Porcine respiratory and reproductive syndrome virus (PRRSV) was used as the outgroup to root the tree. Scale bar at the lower left indicates 0.1 nucleotide substitutions per site.