TABLE 3.

Ratio of synonymous substitutions per synonymous site (d_S) to nonsynonymous substitutions per nonsynonymous site (d_N)

Region	dS	dN	dS/dN
Whole gene	0.33	0.04	9.65
TM domainsa	0.22	<0.01	33.84
CP domainsb	0.17	0.05	3.37
PP domainsc	0.15	0.11	1.45
PP2 domain	0.09	0.15	0.49

^aEight putative transmembrane domains.

^bFour cytoplasmic domains (CP2, CP3, CP4, and CP5).

^cFour periplasmic domains (PP1, PP2, PP3, and PP4).