Fig. 3.

Maximum-likelihood phylogenetic tree constructed using MEGA 5.02 software with the WAG model and 1,000 bootstrap replicates, representing the genetic relationships within the order Nidovirales. RefSeq accession numbers referred to in the trees are as follows: NC_001846 (MHV, strain A59), NC_002645 (HcoV 229E), NC_004718 (human SARS virus), NC_008516 (white bream virus), NC_007447 (Breda virus), AF353511 (PEDV, strain CV777), DQ310701 (Berne virus), Z34093 (TGEV, strain Purdue), M94356 (IBV, strain Beaudette), U15146 (LDV, strain Plagemann), U87392 (PRRSV, strain VR-2332). a1, unrooted RdRp tree; a2, rooted RdRp tree; b1, unrooted 3CLpro tree; b2, rooted 3CLpro tree