Extended Data Fig. 7 | The evolutionary history of odorant receptors in
terrestrial sauropsids. The relationship among odorant receptors was
inferred using the neighbour-joining method. The unrooted tree contains 3,213
amino acid sequences. Branches are coloured according to the following
categories: green, tuatara; blue, birds (G. gallus and Taeniopygia guttata);
red, snakes (Notechis scutatus, Ophiophagus hannah, Protobothrops
mucrosquamatus, Pseudonaja textilis, P. bivittatus and Thamnophis sirtalis);
orange, lizards (A. carolinensis and Pogona vitticeps); and purple, gecko
(Gekko japonicas). Bootstrap support values above 75% (1,000 replicates) are
indicated for major branch splits relating to the different odorant receptor
groups and branches leading to the species-specific odorant receptor
expansions in birds (group γ–c) and tuatara (*).