Assume that a trait is caused by the homozygous state of a gene that is recessive and autosomal.Nine percent of the individuals in a given population express the phenotype caused by this gene.What percentage of the individuals would be heterozygous for the gene? Assume that the population is in Hardy- Weinberg equilibrium.
A)91%
B)9%
C)42%
D)58%

Question

Quizplus · Accepted Answer

Under Hardy-Weinberg equilibrium, if 9% (0.09) of the population expresses the recessive phenotype, then q^2 = 0.09, where q is the frequency of the recessive allele. Solving for q gives q = 0.3. The frequency of the dominant allele, p, is 1 - q = 0.7. The heterozygous frequency is 2pq = 2(0.7)(0.3) = 0.42, or 42%.

Assume That a Trait Is Caused by the Homozygous State