In an insect species, survival in agricultural fields regularly sprayed with insecticide is determined by the genotype for a detoxification enzyme encoded by a gene with two alleles, A and D. Which of the following statements is consistent with the data? $$\begin{array} { | l | l | }
\hline \text { Genotype } & \text { Relative Fitness } \
\hline \mathrm { AA } & 1.00 \
\hline \mathrm { AD } & 0.70 \
\hline \mathrm { OD } & 0.05 \
\hline
\end{array}$$
A) Directional selection will increase the frequency of the A allele at a pace determined by the intensity of natural selection.
B) The D allele frequency will change faster as it gets less frequent.
C) Eventually, natural selection should lead to a balanced polymorphism.
D) This will likely lead to the frequency of the A allele being eliminated (f=0.0) and the D allele being fixed (f=1.0).
E) Both the A and D alleles should reach stable equilibrium frequencies that are maintained in a steady state.

Question

In an insect species, survival in agricultural fields regularly sprayed with insecticide is determined by the genotype for a detoxification enzyme encoded by a gene with two alleles, A and D. Which of the following statements is consistent with the data? $$\begin{array} { | l | l | } 
\hline \text { Genotype } & \text { Relative Fitness } \
\hline \mathrm { AA } & 1.00 \
\hline \mathrm { AD } & 0.70 \
\hline \mathrm { OD } & 0.05 \
\hline
\end{array}$$
A) Directional selection will increase the frequency of the A allele at a pace determined by the intensity of natural selection.
B) The D allele frequency will change faster as it gets less frequent.
C) Eventually, natural selection should lead to a balanced polymorphism.
D) This will likely lead to the frequency of the A allele being eliminated (f=0.0) and the D allele being fixed (f=1.0).
E) Both the A and D alleles should reach stable equilibrium frequencies that are maintained in a steady state.

Quizplus · Accepted Answer

Given the relative fitness values, individuals with the AA genotype have the highest fitness (1.00), indicating that the A allele confers a survival advantage in the presence of insecticide. Therefore, directional selection will favor the A allele, increasing its frequency in the population over time. The pace of this increase will depend on the strength of the selection pressure, i.e., the intensity of natural selection.

In an Insect Species, Survival in Agricultural Fields Regularly Sprayed