Question

Polydactyly is an inherited trait that results in extra fingers or toes. In the United States 0.1% of the population exhibits polydactyly. People with polydactyly have the genotype Pp, where P represents the allele that causes polydactyly and p represents the normal allele of this gene. Which of the following is true?
a. There is not enough information to answer this question.
b. The two alleles, P and p are at approximately equal frequencies in the US population.
c. The P allele is less frequent in the US than the p allele.
d. The P allele is more frequent in the US than the p allele.

Answer 1

Answer:

c. The P allele is less frequent in the US than the p allele.

Explanation:

If people with the heterozygous genotype "Pp" present polydactyly, only people with the genotype "pp" will not present polydactyly. Since 99.9% of the population do not exhibit polydactyly, then it can be concluded that the "p" allele is much more frequent in the US than the "P" allele.

Therefore, the answer is:

c. The P allele is less frequent in the US than the p allele.