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. Author manuscript; available in PMC: 2017 Jun 8.
Published in final edited form as: Science. 2016 Oct 21;354(6310):336–339. doi: 10.1126/science.aaf9070

Fig. 3. Phenotypic effects of substitutions at β83 are conditional on genetic background.

Fig. 3

(A) The engineered G83S mutation produced a significant reduction in P50(KCl+IHP) (increase in Hb-O2 affinity) in the reconstructed Hb of the hummingbird ancestor. (B) The engineered A67V and N83S mutations produced additive reductions in P50(KCl+IHP) in the reconstructed Hb of the flowerpiercer ancestor. Underlining indicates derived (nonancestral) amino acids. (C) Diagrammatic tree with time-scaled branch lengths showing internal nodes that we targeted for ancestral protein resurrection. Scale bar, 10 million years. (D) N/G83S mutations produced significant increases in Hb-O2 affinity (expressed as reductions in P50(KCl+IHP)) in the ancestors of hummingbirds and flowerpiercers. Substitutions at the same site produced no detectable effects in Anc Neoaves or Anc Neornithes.