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. Author manuscript; available in PMC: 2014 Jul 15.
Published in final edited form as: Nature. 2014 Feb 16;508(7495):254–257. doi: 10.1038/nature13016

Extended Data Figure 3. Branch-site REL analyses to test for episodic diversifying selection.

Extended Data Figure 3

The branches are coloured to depict the proportion of substitutions along each branch that are under purifying selection (with dN/dS < 1: blue), the proportion evolving neutrally (with dN/dS = 1: gray), or under diversifying selection (with dN/dS > 1: red). In every gene, almost every site in every branch evidently evolved under purifying selection. In a few branches, a small proportion of sites show evidence of positive selection (e.g. the branch between AIV and equine H7N7 in NS1/2). However, the proportion is so small that there seems to be no conceivable way that episodic diversifying selection occasioned by host jumps could be driving the overall dating estimates. Even for HA and NA, purifying selection overwhelmingly dominates.