Clusters of Orthologous Groups of proteins (COGs) were delineated by comparing protein sequences encoded in 43 complete genomes, representing 30 major phylogenetic lineages.

• 同源蛋白质簇是通过比较43个完全测序的物种（分别代表30个主要的物种系统发生世系）的蛋白质序列描绘出来的。