Figure 24.2

-The distribution of pocket-mouse coat colors in several Arizona populations is associated with substrate color.Some populations live on light-colored granite substrate,and others live on dark volcanic rock.In Figure 24.2,chart A shows the frequency of the melanic (dark)coat phenotype across six populations.Populations C,D,and E live on dark volcanic rock;populations A,B,and F live on light-colored granite.Chart B shows the frequency of the Melanocortin-1 receptor (Mc1r)allele across these populations.The Mc1r alleles,D and d,differ by four amino acids;mice with DD and Dd genotypes have dark coats,whereas mice with dd genotype are light colored.Which of the following statements best interprets the results shown in charts A and B?
A)Frequency of the D allele is closely associated with the melanic phenotype,but is unrelated to the presence of dark substrate color.
B)Frequency of the D allele is not associated with the melanic phenotype,but is associated with the presence of dark substrate color.
C)Frequency of the D allele is closely associated with both the melanic phenotype and the presence of dark substrate color.
D)Frequency of the D allele is associated neither with the melanic phenotype nor with the presence of dark substrate color.
E)Frequency of the D allele does not vary.

Question

Figure 24.2
 
-The distribution of pocket-mouse coat colors in several Arizona populations is associated with substrate color.Some populations live on light-colored granite substrate,and others live on dark volcanic rock.In Figure 24.2,chart A shows the frequency of the melanic (dark)coat phenotype across six populations.Populations C,D,and E live on dark volcanic rock;populations A,B,and F live on light-colored granite.Chart B shows the frequency of the Melanocortin-1 receptor (Mc1r)allele across these populations.The Mc1r alleles,D and d,differ by four amino acids;mice with DD and Dd genotypes have dark coats,whereas mice with dd genotype are light colored.Which of the following statements best interprets the results shown in charts A and B?
A)Frequency of the D allele is closely associated with the melanic phenotype,but is unrelated to the presence of dark substrate color. 
B)Frequency of the D allele is not associated with the melanic phenotype,but is associated with the presence of dark substrate color. 
C)Frequency of the D allele is closely associated with both the melanic phenotype and the presence of dark substrate color. 
D)Frequency of the D allele is associated neither with the melanic phenotype nor with the presence of dark substrate color. 
E)Frequency of the D allele does not vary.

Quizplus · Accepted Answer

Chart A shows that populations living on dark volcanic rock have a higher frequency of the melanic (dark) coat phenotype compared to those living on light-colored granite. Chart B shows that populations with a higher frequency of the D allele also have a higher frequency of the melanic coat phenotype. Therefore, the frequency of the D allele is closely associated with both the melanic phenotype and the presence of dark substrate color.

Figure 24.2 -The Distribution of Pocket-Mouse Coat Colors in Several Arizona Populations