Mutation — Science definition

Defined in 3 courses:

Where it is taught

In use

A mutation is different from both: a change in the genetic information itself — a change in the DNA sequence.

Inherited Traits, Environment & Mutation

An expression change need not be a DNA mutation, and a mutation need not change expression in every tissue.

Gene Regulation, Mutation & Biotechnology

Once two populations can no longer exchange genes, gene flow between them stops, and mutation, drift, and selection are free to push each population's gene pool in its own direction.

Speciation & Mechanisms of Evolution

Questions using mutation

Problem 1

Does every body-cell mutation pass to offspring?
Answer and explanation

No. Transmission depends on contribution to reproductive genetic material, not simply occurrence anywhere in a body.

Problem 2

Illustrative identical-genotype seedlings: one group receives adequate light and averages 8 cm; another receives low light and averages 5 cm. No sequence change is recorded. Explain the supported environmental comparison and correct a claim that every shorter plant must have acquired a heritable mutation.
Answer and explanation

The supplied record supports an environmental growth comparison, with a 3 cm mean difference under the stated light conditions. It does not document a sequence change or heritable mutation. Actual causal interpretation still depends on the fairness of the comparison and variation. A trait difference alone cannot establish mutation or transmission to offspring.

Calculate the observed 3 cm mean difference.

Use the stated equal-genotype information.

Separate environmental response from undocumented mutation and transmission.

Response criteria

  • Explain the relevant biological process accurately.
  • Use the supplied evidence and show calculation steps with units where needed.
  • Connect a labeled model or mechanism with the claim.
  • State an assumption, evidence limitation, or useful next observation.

Problem 3

A mutation has no visible effect in one setting. Must it be impossible or meaningless?
Answer and explanation

No. Its effect may be small, depend on conditions, or not change the measured trait. A genetic change and a visible phenotype are different observations.

Response criteria

  • Explain the relevant biological process accurately.
  • Use the supplied evidence and show calculation steps with units where needed.
  • Connect a labeled model or mechanism with the claim.
  • State an assumption, evidence limitation, or useful next observation.

Problem 4

Why is not every mutation inherited by an organism’s offspring?
Answer and explanation

A mutation may occur only in body cells and not enter the reproductive lineage.

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