Population Genetics MCAT Practice Question
A population experiences a bottleneck when a volcanic eruption kills 99% of individuals, reducing the population from 100,000 to 1,000. An allele previously at frequency 0.5 is now present at frequency 0.52 in the surviving population. Which evolutionary mechanism best explains the frequency change?
Answer choices
- ANatural selection favoring the allele during the eruption
- BMutation generating additional copies of the allele
- CGenetic drift from random sampling of survivorsCorrect answer
- DGene flow from nearby unaffected populations
- EInbreeding depression reducing allele diversity
- FMeiotic drive causing preferential transmission of the allele in surviving individuals
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