Functional divergence
Encyclopedia
Functional divergence is the process by which genes, after gene duplication
, shift in function from an ancestral function. Functional divergence can result in either subfunctionalization
, where a paralog specializes one of several ancestral functions, or neofunctionalization, where a totally new functional capability evolves. It is thought that this process of gene duplication and functional divergence is a major originator of molecular novelty and has produced the many large protein families that exist today .
Many well known protein families are the result of this process, such as the ancient gene duplication event that led to the divergence of hemoglobin
and myoglobin
, the more recent duplication events that led to the various subunit expansions (alpha and beta) of vertebrate hemoglobin
s , or the expansion of G-protein alpha subunits
Gene duplication
Gene duplication is any duplication of a region of DNA that contains a gene; it may occur as an error in homologous recombination, a retrotransposition event, or duplication of an entire chromosome.The second copy of the gene is often free from selective pressure — that is, mutations of it have no...
, shift in function from an ancestral function. Functional divergence can result in either subfunctionalization
Subfunctionalization
Subfunctionalization is a model that explains the process by which duplicated genes remain functional in a genome. Duplicated genes are frequently formed in eukaryotic genomes and are thought to be initially redundant in function. One of the extra copies is usually under relaxed selection and...
, where a paralog specializes one of several ancestral functions, or neofunctionalization, where a totally new functional capability evolves. It is thought that this process of gene duplication and functional divergence is a major originator of molecular novelty and has produced the many large protein families that exist today .
Many well known protein families are the result of this process, such as the ancient gene duplication event that led to the divergence of hemoglobin
Hemoglobin
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...
and myoglobin
Myoglobin
Myoglobin is an iron- and oxygen-binding protein found in the muscle tissue of vertebrates in general and in almost all mammals. It is related to hemoglobin, which is the iron- and oxygen-binding protein in blood, specifically in the red blood cells. The only time myoglobin is found in the...
, the more recent duplication events that led to the various subunit expansions (alpha and beta) of vertebrate hemoglobin
Hemoglobin
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...
s , or the expansion of G-protein alpha subunits