. . . "Definition: The biological source of an entity (e.g. protein, RNA or DNA). Some entities are considered source-neutral (e.g. small molecules), and the biological source of others can be deduced from their constituentss (e.g. complex, pathway).\nExamples: HeLa cells, human, and mouse liver tissue."^^ . "Definition: The biological source of an entity (e.g. protein, RNA or DNA). Some entities are considered source-neutral (e.g. small molecules), and the biological source of others can be deduced from their constituentss (e.g. complex, pathway).\nExamples: HeLa cells, human, and mouse liver tissue."^^ . "Definition: The biological source of an entity (e.g. protein, RNA or DNA). Some entities are considered source-neutral (e.g. small molecules), and the biological source of others can be deduced from their constituentss (e.g. complex, pathway).\nExamples: HeLa cells, human, and mouse liver tissue."^^ . . . . . . . . . . . . .