Table 1.

Reported evidence of positive selection based on the McDonald-Kreitman test.

Group	Species	Evidence of positive selectiona (%)	References
Fungi	2	0 (0%)	[33]
Plantsb	13	4 (31%)	[25–27, 30, 79]
Bacteria	14	6 (43%)	[23, 24]
Vertebrates	3	2 (67%)	[17, 18, 22]
Insectsb	6	6 (100%)	[13, 15, 37, 80–82]
All	38	18 (47%)

^aEvidence for positive selection is based on a significant excess of nonsynonymous divergence based on the MK test.

^bThere are both positive and negative reports of positive selection for some species.