A set of proteins that have evolved from a common ancestral protein and share an evolutionary history. Duplication of an ancestral gene gives rise to a duplicate protein that becomes available to evolution and can diverge in structure and function over evolutionary time. Other mechanisms of protein evolution, such as exon shuffling (see intron), can also be involved. The evolutionary histories linking members of a protein family can be deduced from the extent and molecular configurations of homologous amino acid sequences and structures. Families are arranged in a hierarchy, with closely related proteins comprising subfamilies and related families grouped to form superfamilies.
Subjects: Biological Sciences — Chemistry.