Fig. 3: Evolution of flower symmetry and TCP gene family.

Left, a phylogenetic tree of the flowering plants derived from their divergence time based on orthologues of single-gene families. Three red stars show the whole-genome triplication and two green stars the duplication events (http://chibba.agtec.uga.edu/duplication/). Right, B represents bilateral flower symmetry and R radial flower symmetry; Asterid, Rosid, Basal rosid, Basal eudicot, Monocot and Basal angiosperm represent the clade names, respectively. Total numbers of TCP family genes, Class I PCF, Class II CIN and Class II CYC/TB1 are shown from left to right. The asterisk indicates the sequenced genome of species of Medicago truncatula with flower radial symmetry, but flowers of most Medicago species have bilateral symmetry. The double asterisk indicates Lotus corniculatus in which three TCP genes were identified but a functional TCP gene was not detected in its genome. Four-pointed stars denote flowers with bilateral symmetry with their photos from PPBC (http://www.plantphoto.cn).