Table 1.

The evolutionary divergence of the SI and N genes between IBV groups.

Gene	Group
	TW-US	TW-CH	US-CH
SI	0.194 ± 0.007	0.179 ± 0.007	0.203 ± 0.007
N 1–1230 nt	0.110 ± 0.007	0.131 ± 0.007	0.124 ± 0.007
N 1–600 nt	0.080 ± 0.008	0.128 ± 0.011	0.121 ± 0.011
N 601–1230 nt	0.138 ± 0.011	0.135 ± 0.011	0.127 ± 0.010