Localization of the SNPs on the envelope genes. Characteristic domains of the envelope proteins are depicted as in Figure 1B. The gray frames at the end of H3, R and F(c)2 genes represent short open reading frames present downstream of the stop codon. Mutations are represented along the protein sequence, with the number corresponding to the amino acid affected by the SNP. Synonymous mutations are indicated above the protein frame. Non-synonymous (with stop mutations indicated) and indel mutations (with frame shifting mutations underlined) are indicated below the protein frame.