The genes encoded in your DNA result in the production of proteins that perform specific functionswithin your cells. Various environmental factors and spontaneous events can lead to changes in genes.These changes, called mutations, can lead to alterations in the structure and activity of the proteins yourcells use in their daily activities. In other words, changes to your genotype can result in changes to yourphenotype. We all have mutations in most of our body cells—yet we are, for the most part, normal andfunctional human beings.