The PANTHER (Protein ANalysis THrough Evolutionary Relationships) Classification System is a unique resource that classifies genes by their functions, using published scientific experimental evidence and evolutionary relationships to predict function even in the absence of direct experimental evidence. Proteins are classified by expert biologists according to:

• Gene families and subfamilies, including annotated phylogenetic trees
• Gene Ontology classes: molecular function, biological process, cellular component
• PANTHER Protein Classes
• Pathways, including diagrams

PANTHER is part of the Gene Ontology Reference Genome Project.

PANTHER is supported by a research grant from the National Institute of General Medical Sciences [grant GM081084] and maintained by the Evolutionary Systems Biology Group at SRI.