Functional classification of haloarchaeal orthologous groups (HOGs) for nine haloarchaea. Predicted functions were assigned to core (9 genomes) and accessory (2 - 8 genomes) HOGs based on association with COGs. Several HOGs were associated with one or more COG and all predicted functions are illustrated. Based on predicted functions, HOGs were classified as likely involved in information transfer and storage (orange), cellular processing and signaling (green), or metabolism (red). Predicted functions could not be assigned to HOGs associated with poorly characterized COGs (purple) or with no associated COG (blue).