This chapter examines the role of semantic genes and the metalinguistic system in semantic computing and description. It elaborates on the Natural Semantic Metalanguage (NSM) theory, analyzing the function of semantic primitives in conceptual semantics and exploring their application in dictionary definitions—particularly in addressing circular interpretation. The chapter then introduces the concept of semantic genes, comparing them with other semantic analysis methods. Furthermore, it details the features and classification of semantic genes and proposes a metalinguistic system for their description, incorporating semantic gene units and descriptive symbols for gene structures.