environmental factors such as temperature, sunlight, or humidity can affect whether the gene's potential is actually expressed. A human with a gene for great height will not achieve the tallest height possible if kept on a starvation diet. Penetrance is the term for the percentage of people with genes coding for the expression of a character who actually express the character. Expressivity is term for the extent to which a phenotype is expressed when affected by environmental factors. Thus, individuals are a product both of their genes and the environment, expressions of characters being dependent on the potentiality coded by the genes tempered by the influence of the environment.
