Q.6 A random fluctuation in gene frequency is called
(A) Genetic drift
(B) Genetic load
(C) Panmixis
(D) Genetic shift
Genetic Drift: Random Fluctuation in Gene Frequency Explained
Genetic drift represents random changes in allele frequencies within a population due to chance events. This mechanism is crucial in evolutionary biology, particularly in small populations where it can lead to significant genetic shifts over generations.
Correct Answer
The correct answer is (A) Genetic drift. A random fluctuation in gene frequency is precisely defined as genetic drift, involving unpredictable changes in allele frequencies from one generation to the next due to sampling error in finite populations.
Genetic Drift Details
Genetic drift acts independently of natural selection, affecting all alleles randomly rather than based on fitness. It is more pronounced in small populations, potentially causing alleles to become fixed or lost entirely, reducing genetic diversity. Examples include the bottleneck effect, where a population crash leaves a non-representative sample of alleles, and the founder effect, seen in isolated groups like island species.
Option Explanations
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(A) Genetic drift: Describes random, chance-based fluctuations in gene frequencies, a key evolutionary force alongside selection and mutation.
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(B) Genetic load: Refers to the cumulative burden of deleterious alleles in a population that reduce overall fitness, not random fluctuations.
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(C) Panmixis: Indicates random mating within a population (also called panmictic), which maintains Hardy-Weinberg equilibrium but does not involve frequency changes.
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(D) Genetic shift: Not a standard term; sometimes confused with gene flow or directional selection, but lacks the random nature of drift.
