Before the flaw, what is more important: the application – finding the hidden functions of genes/proteins by searching every part of the gene sequence, every which way it could be arranged or rearranged to code for a new or existing function.
Now for the flaw in the current system:
As a rule, genes are more pleiotropic than is believed.
Consequently, mutations are more pleiotropic than is believed.
Consequently, even when a geneticist has exhaustively defined the consequences of a mutation, misunderstandings of the consequences of mutations are more common than is believed. The genetics database is corrupted with all kinds of errors of misinterpretation.
Add that source of misunderstanding to another prolific source of misinterpretations – the underestimation of the effects of nutrient deficiencies -always plural, as there are thousands of possible conditionally essential nutrients – on enzymes with some redundancy or partial functionality.
Add that to an evolutionary fact: nature optimizes growth and reproduction better than it optimizes maintenance and repair. Consequently, even when we make our own nutrients (part of routine maintenance), it is highly unlikely that we ever make the optimal amount of any of them. Thus, even when we eat properly, we are suffering the consequences of nutritional shortfalls, and we really suffer whenever we consume empty calories, and as a group, Americans are consuming lots of empty calories, as anyone walking the aisles of a supermarket can attest.
Note on chemically defined animal nutrition and human total parenteral nutrition: by definition, these lack the accessory nutrients in good food, and the victims of these treatments cannot possibly be at the optimal level for all of the thousands of accessory nutrients. However, they can be in the acceptable range for a very long time before outright conditional deficiencies develop in some of these accessory nutrients.