They tried to alter a gene that causes the deadly blood condition thalassemia.

The study found that high-fat diets can alter the genes that encode our circadian clocks.

They found disturbed sleep patterns altered a gene involved in everything from our waking rhythms to cell division.

This fast-growing field, known as epigenetics, focuses on the ways in which environmental effects can change the expression of a specific gene without altering the gene itself.

Each of these mutations alters the gene's protein product (i.e., the enzyme), sometimes severely inhibiting its function.