Figure 4

Phylogenies of three starch biosynthesis enzymes exhibiting functional specialization. A: Starch synthase gene family; B: Branching enzyme gene family; C: Debranching enzyme gene family. Paralogs are identified by species name. Phylogenies are rooted with Prochlorococcus marinus and Synechoccus sp. The scale is 0.1 substitutions per site. Nodes with bootstrap values lower than 90% were aggregated into rakes. Black circles indicate duplication events: 1 through n (n being 6 in A, 3 in B and 2 in C). Branches (a or b) emerging from duplications D1 through Dn were tested for deviation from non-neutral evolution. Corresponding outgroup sequences used to infer ancestral states are followed by duplication names in square brackets. Branches found to have evolved under positive selection are colored in red.