Figure 7. The most parsimonious hypothesis to explain the evolution of HECT genes in plants.

Red rectangles correspond to gene losses and black arrows to gene emergences. Subfamilies are indicated with roman numerals; O means “other”, indicating the presence of an additional gene in green algae (see Figure 1). The numbers in the boxes correspond to the genes deduced to exist in the ancestors of the corresponding lineages. The loss of a Subfamily IV gene in angiosperms is supported by a single fragment of a putative gymnosperm Subfamily IV gene (see text), so it must be considered a provisional result, until additional sequences are available.