Makes a lot of sense to me.
Gene duplication is believed to play a major role in evolution
; this stance has been held by members of the scientific community for over 100 years. Susumu Ohno
was one of the most famous developers of this theory in his classic book Evolution by gene duplication
Ohno argued that gene duplication is the most important evolutionary force since the emergence of the universal common ancestor
Major genome duplication
events are not uncommon. It is believed that the entire yeast genome
underwent duplication about 100 million years ago. Plants
are the most prolific genome duplicators. For example, wheat
is hexaploid (a kind of polyploid
), meaning that it has six copies of its genome.
The duplication of a gene results in an additional copy that is free from selective pressure. One kind of view is that this allows the new copy of the gene to mutate without deleterious consequence to the organism. This freedom from consequences allows for the mutation of novel genes that could potentially increase the fitness of the organism or code for a new function. An example of this is the apparent mutation of a duplicated digestive gene in a family of ice fish
into an antifreeze gene.
Another view is that both copies are equally free to accumulate degenerative mutations, so long as any defects are complemented by the other copy. This leads to a neutral "subfunctionalization" or DDC (duplication-degeneration-complementation) model,
in which the functionality of the original gene is distributed among the two copies.
The two genes that exist after a gene duplication event are called paralogs
and usually code for proteins
with a similar function and/or structure. By contrast, orthologous
genes are ones which code for proteins with similar functions but exist in different species, and are created from a speciation
event. (See Homology of sequences in genetics