How does a founder event influence allele frequencies and diversity in a new population?

How does a founder event influence allele frequencies and diversity in a new population?

• A. Frequencies remain identical to source
• B. The subset leads to different allele frequencies due to sampling error
• C. Variation increases
• D. No alleles lost

Answer: (B)

When a new population is started by a small group, the allele makeup of that group can differ from the larger source population simply by chance. This is the founder effect, a form of genetic drift that is pronounced in small populations. Because only a tiny subset of the original gene pool establishes the new population, the frequencies of alleles can shift unexpectedly; some alleles present in the source may be underrepresented or absent in the founders, and others may be overrepresented. This leads to different allele frequencies in the new population and usually a reduction in overall genetic diversity compared with the source population. The statement that best describes this is that the subset leads to different allele frequencies due to sampling error. The other options mischaracterize the outcome: frequencies wouldn’t necessarily stay identical to the source, diversity typically does not increase, and alleles can indeed be lost during the founding event.

When a new population is started by a small group, the allele makeup of that group can differ from the larger source population simply by chance. This is the founder effect, a form of genetic drift that is pronounced in small populations. Because only a tiny subset of the original gene pool establishes the new population, the frequencies of alleles can shift unexpectedly; some alleles present in the source may be underrepresented or absent in the founders, and others may be overrepresented. This leads to different allele frequencies in the new population and usually a reduction in overall genetic diversity compared with the source population. The statement that best describes this is that the subset leads to different allele frequencies due to sampling error. The other options mischaracterize the outcome: frequencies wouldn’t necessarily stay identical to the source, diversity typically does not increase, and alleles can indeed be lost during the founding event.