Evolution and speciation · USMLE Step 1

Which process introduces new heritable variation into a population that can be acted upon by evolutionary forces?

  1. Genetic drift
  2. Mutation
  3. Gene flow
  4. Adaptive radiation
Show answer and explanation

Correct answer: Mutation

Mutation produces novel alleles in gametes, providing the raw genetic variation necessary for evolution; without mutation, other mechanisms have no new variants to act upon.

Difficulty: Medium Question 14 of 20

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