One mutation vs two amino acid substitutions
A two-amino acid change in the hemagglutinin of the 1918 influenza virus abolishes transmission (2007) …a predominant human alpha-2,6 sialic acid binding preference is essential for optimal transmission of this pandemic virus. These findings confirm an essential role of hemagglutinin receptor specificity for the transmission of influenza viruses among mammals. The two amino acid change … One mutation vs two amino acid substitutions
