Venn diagrams displaying the distributions of 1,733 FSF domains (a), 1,924 terminal GO terms (b), and 1,148 RNA families (c) in the genomes of the three domains of life. FSF domain data was taken from Nasir et al. [122, 123] and included 981 completely sequenced proteomes from 70 Archaea, 652 Bacteria, and 259 Eukarya. Terminal GO terms corresponding to the “molecular function” hierarchy defined by the GO database [118] were identified in 249 free-living organisms, including 45 Archaea, 183 Bacteria, and 21 Eukarya (data taken from [123]). The Venn diagram of RNA families and the distribution of Rfam clans and families in organisms were taken from Hoeppner et al. [129] and their Dataset S1. Shown below are distribution patterns for FSFs, GO terms, and RNA families that are present in more than 60% of the organisms examined (). All distributions highlight maximum sharing in the ancient ABE and BE taxonomic groups and minimal sharing in archaeal taxonomic groups.