Immanent gene action refers to the process by which a gene produces its phenotype without requiring any external factors. Synonyms for this phrase might include intrinsic gene function, innate gene expression, or inherent gene behavior. These terms all suggest that a gene is acting on its own, without any influence from the environment or other genes. Other possible synonyms might include autonomous gene activity or self-sufficient gene regulation. Each of these phrases seeks to capture the idea that genes have a certain level of independence and control over their own expression, even as they interact with other genes and the environment.