Neutral Theory of Molecular Evolution
Updated 2026-08-02
INTRODUCTION
English translation pending.
CORE DEFINITION
Proposed by Motoo Kimura, the neutral theory of molecular evolution holds that the great majority of mutations are selectively neutral, so their fate in a population is determined by random genetic drift rather than by selection. Under this view, the rate of molecular substitution approximates the neutral mutation rate and is largely independent of population size. A parallel neutral theory in ecology, developed by Stephen Hubbell, applies the same logic to species abundance. Key qualification: neutrality is a null model, and selection remains essential for explaining adaptive traits and conserved sequences.
SCAFFOLDING EFFECT
Reduce cognitive load
- Use as null: ask what pattern random drift alone would produce before claiming selection. - Audit survivors: check whether an incumbent exists because it is better or merely because it was early. - Check the scale: apply neutral reasoning to variation with little fitness consequence.
Anchor fast decisions
Most mutations change nothing about fitness, so their frequencies wander randomly across generations until they are lost or fixed. Because this random walk proceeds at a rate set by mutation rather than by population size, neutral variants accumulate steadily over time. Selection is only detectable as a deviation from that baseline, which is why neutrality serves as the reference against which adaptation is tested.
MINIMUM ACTION
In progress 0/1Practice this model in one real situation:
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Source support: Explicit
- zh.wikipedia.orghttps://zh.wikipedia.org/wiki/%E4%B8%AD%E6%80%A7%E6%BC%94%E5%8C%96%E7%90%86%E8%AB%96verified
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