Table 2. McDonald and Kreitman tests.

Species	Gene	FS	FNS	PS	PNS	P-valuea
D. melanogaster	Or63a	28	8	14	6	0.54
	Or65a	24	22	17	8	0.22
	Or65b	37	28	4	6	0.50
	Or65c	28	30	34	6	<0.001***
	Or67a	47	67	17	2	<0.001***
	Or67b	52	9	2	1	0.40
	Or67c	36	6	26	7	0.54
	Or69a	44	47	23	14	0.18
	TOTAL	296	217	137	50	<0.001***
D. pseudoobscura	Or63a	15	6	9	12	0.12
	Or65b1	12	18	22	5	0.003**
	Or65b4	7	7	14	17	1.00
	Or65b5	24	16	21	11	0.81
	Or67a	12	8	32	12	0.39
	Or67b	8	5	4	1	0.61
	Or67c	3	4	24	2	0.011**
	Or69a	18	13	7	7	0.75
	TOTAL	99	77	133	67	0.044*

FS, fixed synonymous substitutions; FNS, fixed nonsynonymous substitutions; PS, polymorphic synonymous substitutions; PNS, polymorphic nonsynonymous substitutions.

*P<0.05;

**P<0.01;

***P<0.001.

^aTwo-tailed Fisher's exact test.