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 (not affecting fitness). The theory was introduced by Motoo Kimura in the late 1960s and early 1970s. Neutral theory is compatible with Darwin's theory of evolution by natural selection: adaptive changes are acknowledged as present and important, but hypothesized to be a small minority of all the changes seen fixed in DNA sequences. Since then, this hypothesis has been tested using the McDonald-Kreitman test, and has not been supported in all species. Even in those species in which adaptive changes are rare, background selection at linked sites may violate neutral theory's assumptions regarding genetic drift.
Read more about Neutral Theory Of Molecular Evolution: Overview, The "neutralist–selectionist" Debate
Famous quotes containing the words neutral, theory and/or evolution:
“The seashore is a sort of neutral ground, a most advantageous point from which to contemplate this world. It is even a trivial place. The waves forever rolling to the land are too far-traveled and untamable to be familiar. Creeping along the endless beach amid the sun-squall and the foam, it occurs to us that we, too, are the product of sea-slime.”
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“A theory if you hold it hard enough
And long enough gets rated as a creed....”
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“Historians will have to face the fact that natural selection determined the evolution of cultures in the same manner as it did that of species.”
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