Table 5.

Estimation of nonsynonymous and synonymous substitution rates in the seven genomes of HCoV-OC43

Gene	Function	HCoV-OC43 substitution rates
		Ka	Ks	Ka/Ks
nsp1	Unknown	0.003	0.01	0.24
nsp2	Unknown	0.003	0.012	0.245
nsp3	Papain-like protease	0.002	0.014	0.17
nsp4	Unknown	0.002	0.011	0.142
nsp5	3C-like protease	0.002	0.004	0.599
nsp6	Unknown	0	0.015	0
nsp7	Predicted replicase	0	0
nsp8	Predicted replicase	0.002	0.008	0.277
nsp9	RNA synthesis protein	0	0.004	0
nsp10	RNA synthesis protein	0	0.003	0
nsp11	Unknown	0	0.06	0
nsp12	RdRp	0.001	0.009	0.066
nsp13	Helicase	0	0.014	0.015
nsp14	Unknown	0.001	0.015	0.065
nsp15	Endoribonuclease-like	0.003	0.015	0.169
nsp16	Putative methyltransferase	0	0.016	0
ns2a	Predicted phosphoesterase	0	0.015	0
HE	Helicase	0.011	0.02	0.542
S	Spike	0.014	0.035	0.402a
ns5a	Unknown	0.003	0
E	Envelope	0.003	0.01	0.299
M	Membrane	0.004	0.019	0.223
N	Nucleocapsid	0.005	0.013	0.369

^aThe K_a/K_s ratio for S genes of the 29 HK strains from 2004 to 2011 was 0.270.