Fig. 4

The landscape of amino acid variation during 2004–2020 determined by Wu-Kabat amino acids variability plotting. A Spike glycoprotein, B Envelop protein, C Membrane protein, D Nucleocapsid protein. The earliest isolated virus, CHN-AH-2004 (GenBank ID: KP757890.1), was used as a query. Y-axes represent the Wu-Kabat variability coefficient values, where the estimation limit is “1”. Above the limit “> 1” represents variations. X-axes represent the amino acid positions relative to the corresponding protein