Question

Distinguish genetic drift from gene flow in terms of (a) how they occur and (b) their implications for future genetic variation in a population.

Short answer

1. Genetic drift occurs within the population due to changes in allele frequencies. Gene flow occurs when alleles are exchanged between two different populations.

2. Genetic drift reduces genetic variation over time, and gene flow increases genetic variation.

Step-by-step solution

Evolutionary forces

According to Hardywienberg equilibrium theory, allele frequencies are continuously changing in populations. The factors that change allele frequencies are called evolutionary forces.Mutation, genetic drift, gene flow, and natural selection are four evolutionary forces.

Mutation brings changes in the gene pool, which leads to genetic variation. If the offspring inherit the variation, it continues in the population through natural selection.

Explanation for part (a)

Random event or sampling error in a population leads to genetic drift. Genetic drift is more likely to occur in a small population. The migration of organisms to another population causes gene flow. Inbreeding or inbreeding through migration is the reason for gene flow.

Explanation for part (b)

As genetic drift occurs in a small population, it reduces genetic variation.There are fewer possibilities to form diversity in a small population.Gene flow occurs in a large population. Inbreeding forms new forms of traits, which leads to genetic variation in organisms.

Genetic diversity is caused by both genetic drift and gene flow. However, gene flow causes more variation than genetic drift due to its occurrence.