Genetics is used as a tool to study living systems because of a key assumption that the phenotypes of loss-of-function mutations on a gene indicate the gene's normal/native functions. I propose that inactivation of a gene not only suppresses the gene's native functions but may also create spurious functions that cause phenotypes irrelevant to the gene's native functions. Such spurious functions represent the otherwise dormant physical/chemical potentials of a living system, do not follow the existing rules built by natural selection, and can hardly be integrated with other functions using empirical data. Thus, the rationale of using loss-of-function phenotypic data to understand a living system is challenged. Fortunately, spurious functions are expected to be evolutionarily unstable while native functions should be conserved, suggesting a means of separating them. I argue that current biology is confused by the undiscerned use of genetic data and suggest a solution.
Keywords: genetic analysis; native function; natural selection; physical/chemical potential.; spurious function.
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