Three ancestral genes and a single large expansion in the Latimeria T2R family. Eighty T2R receptors of Latimeria were compared with T2R receptors of mouse, Xenopus tropicalis, and 5 teleost fishes (species and color code as given for Figure 1). The phylogenetic tree was generated as described for Figure 1; branch support is given as percentage. Asterisks, potential pseudogenes, see Methods for details. For accession numbers and genomic location of Latimeria genes see Additional file 1. Three ancestral genes are indicated by open circles at the respective nodes.