Fig 3.

Selection pressure analysis of the S genes of BatCoV HKU10. (A) Detection of lineage-specific selection pressure. The branch with a P value of <0.01 is highlighted. ω⁺, strength of positive selection; q⁺, proportion of the total branch length influenced by the selective pressure. The scale bar indicates the estimated number of substitutions per 20 nucleotides. (B) Distribution of positively selected sites in S protein genes identified using REL among Hi-BatCoV HKU10 strains from 2005–2010. The receptor-binding domains (RBD) of the S proteins of TGEV, HCoV NL63, and HCoV 229E were mapped previously (3, 14, 74). Homology modeling of the RBD in the S proteins of Ro-BatCoV HKU10 and Hi-BatCoV HKU10 was performed using SwissModel in automated mode (52). The heptad repeat (HR) regions were predicted by using the coiled-coil prediction program MultiCoil2 (61).