Neutral theory of molecular evolution
A theory stating that evolutionary changes particularly at the molecular level arise from genetic drift of mutant alleles that are neutral
Evolution pertains to the gradual progression of changes in the genetic composition of a biological population over successive generations. There are two major mechanisms that lead to evolution. These are natural selection and genetic drift.
Evolution that arises from genetic drift is called neutral theory of molecular evolution. Genetic drift produces random changes in the frequency of traits in a population. One of the possible consequences caused by genetic drift is the disappearance of certain alleles from a population or the new alleles becoming more common within the population. Another possible outcome is the genetically drifting of two populations that had the same genetic structure at the beginning.
The evolutionary changes occurring at the molecular level involves genetic drift of mutant alleles that are neutral, which means that the changes in the genes do not affect the ability of an organism to survive and reproduce.
This theory was first described in 1968 by Motoo Kimura, a Japanese biologist, and later on in 1969 by American biologists Jack Lester King and Thomas Hughes Jukes.