Non-Darwinian Evolution
Encyclopedia
"Non-Darwinian Evolution" is a 1969 scientific paper co-authored by Jack Lester King
and Thomas H. Jukes
that is credited, along with Motoo Kimura
's 1968 paper "Evolutionary Rate at the Molecular Level", with proposing what became known as the neutral theory of molecular evolution
. The paper brings together a wide variety of evidence, ranging from protein sequence comparisons to studies of the Treffers mutator gene in E. coli to analysis of the genetic code to comparative immunology, to argue that most protein evolution is due to neutral mutation
s and genetic drift
. It was published in the May 16, 1969 issue of Science
.
The idea of evolution at the molecular level being driven by the random processes of mutation and genetic drift, largely independent from natural selection
, was controversial at the time; the provocative title further emphasized the break with mainstream evolutionary thought, which was dominated by the synthetic theory of evolution, often referred to as "Neo-Darwinism
". Although they argued for essentially the same conclusion as Motoo Kimura's earlier paper, King and Jukes criticized one of Kimura's central arguments, an estimate of the rate of amino acid change in proteins that according to Kimura would indicate an impossibly high genetic load
if the changes were caused by natural selection. The paper was initially rejected by its reviewers, one of whom was Motoo Kimura's collaborator James F. Crow
, but was published after an appeal. Despite the intentionally inflammatory title and "antiauthoritarian tone"—which according to historian Michael R. Dietrich "undoubtedly struck a nerve", especially since King and Jukes worked at UC Berkeley during that period of political unrest—the paper acknowledges the significance of natural selection; it merely argues against panselectionism (as advocated at the molecular level by G. G. Simpson and Emil L. Smith
in particular). From 1969 until the early 1970s, the concept of neutral mutations driven to fixation
by genetic drift was known as "Non-Darwinian Evolution"; it was subsequently termed the "neutral theory of molecular evolution".
"Non-Darwinian Evolution" generated considerable interest in neutral mutations, and became very influential in the field of molecular evolution
. The response by critics (including direct rebuttals by Bryan Clarke
and Rollin Richmond), and subsequent replies (by King and Jukes, Kimura, and others) marked the beginning of the neutralist/selectionist controversy. In the 1970s and 1980s, Kimura became the chief advocate of the neutral theory, but he adopted a number of King and Jukes' arguments and de-emphasized genetic load.
Jack Lester King
Jack Lester King was an American evolutionary biologist best known for co-authoring a seminal paper on the neutral theory of molecular evolution, "Non-Darwinian Evolution"....
and Thomas H. Jukes
Thomas H. Jukes
Thomas Hughes Jukes was a British-American biologist known for his work in nutrition, molecular evolution, and for his public engagement with controversial scientific issues, including DDT, vitamin C and creationism...
that is credited, along with Motoo Kimura
Motoo Kimura
was a Japanese biologist best known for introducing the neutral theory of molecular evolution in 1968. He became one of the most influential theoretical population geneticists. He is remembered in genetics for his innovative use of diffusion equations to calculate the probability of fixation of...
's 1968 paper "Evolutionary Rate at the Molecular Level", with proposing what became known as the neutral theory of molecular evolution
Neutral theory of molecular evolution
The neutral theory of molecular evolution states that the vast majority of evolutionary changes at the molecular level are caused by random drift of selectively neutral mutants . The theory was introduced by Motoo Kimura in the late 1960s and early 1970s...
. The paper brings together a wide variety of evidence, ranging from protein sequence comparisons to studies of the Treffers mutator gene in E. coli to analysis of the genetic code to comparative immunology, to argue that most protein evolution is due to neutral mutation
Neutral mutation
In genetics, a neutral mutation is a mutation that has no effect on fitness. In other words, it is neutral with respect to natural selection.For example, some mutations in a DNA triplet or codon do not change which amino acid is introduced: this is known as a synonymous substitution. Unless the...
s and genetic drift
Genetic drift
Genetic drift or allelic drift is the change in the frequency of a gene variant in a population due to random sampling.The alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces...
. It was published in the May 16, 1969 issue of Science
Science (journal)
Science is the academic journal of the American Association for the Advancement of Science and is one of the world's top scientific journals....
.
The idea of evolution at the molecular level being driven by the random processes of mutation and genetic drift, largely independent from natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
, was controversial at the time; the provocative title further emphasized the break with mainstream evolutionary thought, which was dominated by the synthetic theory of evolution, often referred to as "Neo-Darwinism
Neo-Darwinism
Neo-Darwinism is the 'modern synthesis' of Darwinian evolution through natural selection with Mendelian genetics, the latter being a set of primary tenets specifying that evolution involves the transmission of characteristics from parent to child through the mechanism of genetic transfer, rather...
". Although they argued for essentially the same conclusion as Motoo Kimura's earlier paper, King and Jukes criticized one of Kimura's central arguments, an estimate of the rate of amino acid change in proteins that according to Kimura would indicate an impossibly high genetic load
Genetic load
In population genetics, genetic load or genetic burden is a measure of the cost of lost alleles due to selection or mutation...
if the changes were caused by natural selection. The paper was initially rejected by its reviewers, one of whom was Motoo Kimura's collaborator James F. Crow
James F. Crow
James F. Crow is Professor Emeritus of Genetics at the University of Wisconsin–Madison.Some of his most significant peer-reviewed contributions were coauthored with Motoo Kimura. His major contribution to the field, however, is arguably his teaching...
, but was published after an appeal. Despite the intentionally inflammatory title and "antiauthoritarian tone"—which according to historian Michael R. Dietrich "undoubtedly struck a nerve", especially since King and Jukes worked at UC Berkeley during that period of political unrest—the paper acknowledges the significance of natural selection; it merely argues against panselectionism (as advocated at the molecular level by G. G. Simpson and Emil L. Smith
Emil L. Smith
Emil L. Smith was an American biochemist who studied protein structure and function as well as biochemical evolution....
in particular). From 1969 until the early 1970s, the concept of neutral mutations driven to fixation
Fixation (population genetics)
In population genetics, fixation is the change in a gene pool from a situation where there exist at least two variants of a particular gene to a situation where only one of the alleles remains...
by genetic drift was known as "Non-Darwinian Evolution"; it was subsequently termed the "neutral theory of molecular evolution".
"Non-Darwinian Evolution" generated considerable interest in neutral mutations, and became very influential in the field of molecular evolution
Molecular evolution
Molecular evolution is in part a process of evolution at the scale of DNA, RNA, and proteins. Molecular evolution emerged as a scientific field in the 1960s as researchers from molecular biology, evolutionary biology and population genetics sought to understand recent discoveries on the structure...
. The response by critics (including direct rebuttals by Bryan Clarke
Bryan Clarke
Professor Bryan Campbell Clarke FRS, born in 1932, is a British geneticist. He is professor emeritus of genetics at the University of Nottingham. Clarke is particularly noted for his work on apostatic selection and other forms of frequency-dependent selection, and work on polymorphism in snails,...
and Rollin Richmond), and subsequent replies (by King and Jukes, Kimura, and others) marked the beginning of the neutralist/selectionist controversy. In the 1970s and 1980s, Kimura became the chief advocate of the neutral theory, but he adopted a number of King and Jukes' arguments and de-emphasized genetic load.