Fig. 1.
Retinal release rates and spectral sensitivities of ancestral RH1 pigments inferred from an amino acid model. (A) Species tree with focal ancestors (circles) and their RH1 half-life values. Sequences for the ancestral Sauria and Archelosauria were identical, and the Sarcopterygii value (shown in italics) was predicted from a near-identical sequence. Significant differences between t1/2 values for adjacent nodes are shown (*P < 0.05; **P < 0.01). (B) Evolutionary changes in RH1 retinal release rate, with plots based on mean values from 3 to 4 assays. (C) Spectral sensitivities and λmax values. (D) Arrhenius activation energies for Tetrapoda (filled circles) and bovine (open circles) RH1.