Fig. 1

The evolution of SM genes in red algae. a Distribution of 215 spliceosomal (SM) protein homologs in 17 red algal (in red color) and Viridiplantae lineages (in green color). Galdieria species are shown in the purple color. The heatmap is based on the sequence identities between human SM proteins and their homologs in the corresponding species. b The putative losses of SM genes in the red algal tree of life. The extent of SM gene loss is indicated by the numbers under branches. The grey circle indicates the most recent common ancestor of red algae. The dashed branches and arrows indicate the three phases of red algal genome reduction