Question

Which of the following is an example of genetic drift?

• A. Individuals from one population migrate and interbreed with members of a different population
• B. An allele increases in frequency due to the increase in fitness it provides to the organism.
• C. A massive storm randomly kills many individuals in a population, changing the frequency of alleles in that population.
• D. Both a and b

Answer 1

The correct option is C A massive storm randomly kills many individuals in a population, changing the frequency of alleles in that population.

Genetic drift occurs when the frequency of alleles in a population changes by random chance. Among the given options, a massive storm that randomly kills many individuals in a population thereby changing the allelic frequency is an example of genetic drift.

Population is the group of individuals of the same species living in a particular geographical area.

Option a: Individuals migrating from one population and interbreeding with members of a different population of the same species is called gene flow or gene migration.

Option b: Change in allele frequency based on biological fitness is natural selection, not genetic drift. An allele that increases in frequency due to the increase in fitness it provides to the organism is an example of natural selection. Natural selection favours the survival of individuals who possess beneficiary alleles and eliminates those who don’t. In this way, the surviving population has the beneficial allele which further increases in frequency over generations.