Relationship of U.S. isolates to genomes of other RHDV isolates. A. Genomes of RHDV isolates including the four U.S. isolates were aligned in CLUSTAL W and 1000 bootstrap replicates were subjected to DNA Distance and Neighbor Joining methods. A consensus tree is shown with bootstrap values greater than 50% placed above tree branches. The U.S. isolates all branched (100% of the time) with a distinct clade of RHDVa isolates from China (box). B. Analysis was repeated as shown in panel A. except that the VP60 coding regions were removed from the genomic sequences. All U.S. isolates continued to branch with the RHDVa isolates from China, despite removal of the RHDVa epitope.