TABLE 1.

Consistency of asymmetric evolution

	S. cerevisiae–C. glabrata		S. cerevisiae–S. castellii		C. glabrata–S. castellii
Locus statusa	Loci	%	Loci	%	Loci	%
A.
Fast (sp. 1) is fast (sp. 2)	58	89	55	89	37	90
Fast (sp. 1) is slow (sp. 2)	7	11	7	11	4	10
Total no. of loci	65	100	62	100	41	100
	P = 1.06e-6		P = 4.37e-6		P = 7.94e-5
B.
Shared branch is fast	52	90	45	82	33	89
Shared branch is slow	6	10	10	18	4	11
Total fast (sp. 1) is fast (sp. 2)	58	100	55	100	37	100
	P = 4.81e-6		P = 5.60e-4		P = 3.15e-4

The data set used is set 3 (2:2 categories; supplemental Table 1 at http://www.genetics.org/supplemental/). Rates of amino acid divergence are examined on (A) terminal branches and (B) shared branches. P-values are from Fisher's exact two-tail tests against neutral expectation.

^a“Fast (sp. 1) is fast (sp. 2)” means that the same ohnolog is the faster-evolving one in both species. “Fast (sp. 1) is slow (sp. 2)” means that the faster copy in one species is the slower-evolving copy in the other. “Shared branch is fast” means that the shared branch leading to the consistently faster orthologs is the faster of the two shared branches. “Shared branch is slow” means that the shared branch leading to the consistently faster orthologs is the slower shared branch.