Table 4. PRFMLE analysis of selection pressures detected from interspecies and interstrain analysis of pil and opa genes of N. meningitidis and N. gonorrhoeae.

Gene	Species	Interpecies or interstrain analysis	γ (95% confidence interval)	Significance (p value)	Outcome
pil n = 219		Interspecies	3.44 ± 3.11	3.78 x 10−5	Positive selection
	N. meningitidis n = 71	Interstrain	2.47 ± 2.84	6.12 x 10−3	Positive selection
	N. gonorrhoeae n = 148	Interstrain	3.22 ± 3.52	7.73 x 10−4	Positive selection
opa n = 86		Interspecies	3.44 ± 3.11	3.78 x 10−5	Positive selection
	N. meningitidis n = 17	Interstrain	2.68 ± 2.64	8.67 x 10−4	Positive selection
	N. gonorrhoeae n = 69	Interstrain	3.42 ± 3.36	1.40 x 10−4	Positive selection