Sites that distinguish the mA3 genes in virus-restrictive C57BL and virus-nonrestrictive BALB/c mice, and sites under positive selection.

aThe BALB/c residue is given where it differs from C57BL.
bCalculated using PAML for two sets of sequences. The probabilities were determined using Codon Table model F61 and selection Model 8 on the taxonomy-based trees. Sites under selection with probabilities >0.95 are in bold, and strongly selected sites with P>0.99 are also underlined. Use of the codon frequency model F3X4 identified selection with P>0.95 at codon 181 and with P>0.99 at codon 183 (Table S2).