Table 2.

Amount of Positive Selection Detected on Different Branches of the Analyzed Phylogeny.

Branch Namea	Lineage Delineated	Fraction of Positively Selected Gene Families	Number of Positively Selected Gene Familiesb
Acep	Atta cephalotes	0.056	144
Aech	Acromyrmex echinatior	0.043	109
Sinv	Solenopsis invicta	0.029	85
Pbar	Pogonomyrmex barbatus	0.038	80
Cflo	Camponotus floridae	0.017	65
Lhum	Linepithema humile	0.036	97
Hsal	Harpegnathos saltator	0.020	76
1	Attini	0.0088	16
2	Myrmicinae	0.0071	10
3	Myrmicinae	0.0087	16
4	Formicoid	0.0072	17
5	Formicoid	0.025	58
6	Formicidae	0.030	87
7	Aculeata	0.10	176
8	Hymenoptera/Apocrita	0.39	762
All above branches except 7 and 8	Formicidae	0.20	830
All above branches	Hymenoptera/Apocrita	0.43	1,832

^aAs illustrated in figure 1.

^bBranches of gene families trees can be merged if genes are missing (or removed for quality reasons), and the resulting branches do not correspond to canonical branches defined by the species topology (fig. 1). When positive selection is found on such branches, it was not counted in branch-specific numbers displayed in table 2, but it was counted when a whole lineage was considered (e.g., Hymenoptera).