Table 2. Autoxidation rates of rHbs representing bar-headed goose, greylag goose, their reconstructed ancestor (AncAnser), and all possible mutational intermediates connecting AncAnser with each of the two descendant species.

For the bar-headed goose mutants (all mutational intermediates between wildtype bar-headed goose and AncAnser), three-letter genotype codes denote amino acid states at α18, α63, and α119 (amino acid abbreviations underlined in bold = derived [non-ancestral]). At these same three sites, AncAnser is ‘GAP’ the wildtype genotype of bar-headed goose is ‘SVA’. For the greylag goose mutants (all mutational intermediates between wildtype greylag goose and AncAnser), two-letter genotype codes denote amino acid states at β4 and β125. At these same two sites, AncAnser is ‘TD’ the wildtype genotype of greylag goose is ‘SE’.

rHb	Autoxidation rate, h-1 (± SEM)
Bar-headed goose	0.109 ± 0.017
Greylag goose	0.112 ± 0.019
AncAnser	0.170 ± 0.014
Bar-headed goose mutants
GAA	0.164 ± 0.026
GVP	0.399 ± 0.067
SAP	0.149 ± 0.011
GVA	0.424 ± 0.036
SAA	0.154 ± 0.013
SVP	0.159 ± 0.009
Greylag goose mutants
SD	0.132 ± 0.014
TE	0.156 ± 0.019