What term describes random fluctuations in allele frequencies, especially in small populations?

What term describes random fluctuations in allele frequencies, especially in small populations?

• A. Genetic drift
• B. Founder effect
• C. Gene flow
• D. Mutation

Answer: (A)

Genetic drift describes random fluctuations in allele frequencies from one generation to the next, and these changes are especially noticeable in small populations because sampling error has a larger impact when there are fewer individuals. Over time, drift can cause alleles to become fixed or lost purely by chance, regardless of whether they help or hinder survival. The founder effect is a specific instance of this process that occurs when a new population is started by a very small group, so the new population’s genetic makeup reflects those founders by luck. Gene flow involves the movement of alleles between populations via migration and tends to homogenize populations rather than cause random shifts within a single one. Mutation introduces new alleles but is about new variation arising, not about random frequency changes in an existing gene pool. So the concept described here is genetic drift.

Genetic drift describes random fluctuations in allele frequencies from one generation to the next, and these changes are especially noticeable in small populations because sampling error has a larger impact when there are fewer individuals. Over time, drift can cause alleles to become fixed or lost purely by chance, regardless of whether they help or hinder survival. The founder effect is a specific instance of this process that occurs when a new population is started by a very small group, so the new population’s genetic makeup reflects those founders by luck. Gene flow involves the movement of alleles between populations via migration and tends to homogenize populations rather than cause random shifts within a single one. Mutation introduces new alleles but is about new variation arising, not about random frequency changes in an existing gene pool. So the concept described here is genetic drift.