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Neutral, Beneficial, and Deleterious Mutations

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State

A mutation's effect on fitness falls into one of three categories: deleterious, reducing survival or reproduction; beneficial, improving it; or neutral, changing neither.

Show

A point mutation in a non-coding region, per Unit 6's Bio 1297, changing fitness not at all is a neutral mutation.

Watch for

Most new mutations are neutral or deleterious — beneficial is the least common outcome, not the default.