Genetic drift refers to changes in allele frequencies that occur primarily due to:
Answer and explanation
Correct answer: D. Chance events and sampling errors in small, isolated populations
- Step 1: Genetic drift (the Sewall Wright effect) is the random fluctuation of allele frequencies from generation to generation.
- Step 2: It is caused purely by sampling error during gamete transmission and chance mortality.
- Step 3: While negligible in very large populations, genetic drift has powerful evolutionary effects in small populations, potentially causing fixation or loss of alleles regardless of their adaptive value.
Answer
Chance events and sampling errors in small, isolated populations.
Why not the others: Natural selection is a non-random, fitness-driven process; Gene mutations occur at very low frequencies ( to ); Gene flow homogenizes populations rather than producing random drift.
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