One of the forms of gene expression is the physical development of a cellular organelle, of a new type of cell and, consequently, of a new tissue or organ and finally a new living being who was genetically encoded but that did not exist for its lack of a nutritional element or the lack of an environmental chemical agent. Through this mechanism geological changes have influenced the development and selection of different forms of plants and, at the same time, different plants have influenced the development of different forms of animal life.

We can illustrate this basic information with an example (1) genetic basis for the production of chlorophyll in plants is expressed by the presence of geological origin CO2 (2) plans, accordingly, enrich the atmosphere and seas with O2 and this gene expression allows the production of hemoglobin in animals (3) if we observe the chemical structure of both molecules we may observe that they have an identical ring. One of them contains Mg (chlorophyll) and the other one Fe (hemoglobin) which allows it to capture CO2 and O2 meanwhile the other molecule captures O2 and releases CO2.

At the same way, the presence of some plant nutrients in gene expression have originated new cells and animal organs whose metabolism is linked to such basic substances that are called pronutrients.

Finally, we may point out that, in reptiles, birds and mammals, some of these pronutrients must be supplied to the embryo in early stages (equivalent to primitive forms of the evolutionary scale) for proper gene expression in specific organs. In this case, pronutrients acquire nutrogenical denomination.

The application in animal nutrition of this knowledge about relationship between animal cells and pronutrients and nutrogenical substances, established hundreds or millions of years ago, in the origin of each tissue, allow us to to restore the physiological function of animal tissues, get good livestock performance by reducing the use of chemicals and improve the health status of animals by reducing the use of drugs.