ABSTRACT
Protein molecules can change through biological evolution. As organisms evolve, their proteins are subjected to random mutations, occasionally resulting in changes to their native structures, physical properties, and/or biological actions. Such variations can become encoded into the genome, so descendant proteins can differ from ancestral proteins. On the large scale, modified biomolecules sometimes lead to new species, as when humans diverged from apes. This chapter describes how protein sequence, structure, and function change through evolution.
