Figure 3.

Evolution of UVS/VS SWS1 pigments in birds. The ancestral states of amino acids at sites 86 and 90 are shown [2]. For the branches in the lower part of the tree, codons 86 and 90 are also shown. Nucleotide changes in these codons are designated with lower case letters. The ancestral avian pigment is derived from that of the green anole (Anolis carolinensis). Where there is inter-Order variation at these sites, all alternatives are shown. Black lines indicate UVS pigments, violet lines represent VS pigments, and dotted lines designate the presence of both UVS and VS pigments within the Order. Adapted from [8,9].