Which event occurs when a small number of individuals colonize a new area, causing the new population to reflect only the founders' alleles?

Which event occurs when a small number of individuals colonize a new area, causing the new population to reflect only the founders' alleles?

• A. Founder Effect
• B. Genetic Bottleneck
• C. Gene Flow
• D. Mutation

Answer: (A)

When a few individuals establish a new population in a different area, the gene pool of that new group is determined by the alleles those founders carry, not the full diversity of the original population. This sampling effect changes allele frequencies by chance and reduces overall genetic variation in the new population. This is the founder effect, a form of genetic drift that happens in small, isolated groups. This isn’t a genetic bottleneck, which describes a drastic reduction in a population’s size within the same location rather than starting a new population elsewhere. It also isn’t gene flow, which would involve individuals moving between populations and mixing alleles, or mutation, which introduces new alleles rather than simply reflecting the founders’ existing alleles.

When a few individuals establish a new population in a different area, the gene pool of that new group is determined by the alleles those founders carry, not the full diversity of the original population. This sampling effect changes allele frequencies by chance and reduces overall genetic variation in the new population. This is the founder effect, a form of genetic drift that happens in small, isolated groups.

This isn’t a genetic bottleneck, which describes a drastic reduction in a population’s size within the same location rather than starting a new population elsewhere. It also isn’t gene flow, which would involve individuals moving between populations and mixing alleles, or mutation, which introduces new alleles rather than simply reflecting the founders’ existing alleles.