The following question(s) are based on information in Hopi E. Hoekstra, Kristen E. Drumm, and Michael W. Nachman, "Ecological Genetics of Adaptive Color Polymorphism in Pocket Mice: Geographic Variation in Selected and Neutral Genes," Evolution 58(6), 2004: 1329-41.
-Refer to the figure above. In their investigation of natural selection on Mc1r alleles (the gene that determines coat color) in Arizona pocket mice, Hoekstra et al. determined the frequency of the D and d alleles in each population. They also determined the frequency of alleles for two neutral mitochondrial DNA genes (genes that do not affect and are not linked to coat color). Why did the researchers include the mitochondrial DNA genes as part of their experimental design?
A) Allele change for the neutral mitochondrial genes serves as an experimental group and gives information on any general background genetic difference among these populations.
B) Allele change for the neutral mitochondrial genes serves as a control and determines coat-color differences among these populations.
C) Allele change for the neutral mitochondrial genes serves as an experimental group and gives information on coat-color differences among these populations.
D) Allele change for the neutral mitochondrial genes serves as a control and gives information on any general background genetic difference among these populations.
E) None of the above answers applies.

Question

The following question(s) are based on information in Hopi E. Hoekstra, Kristen E. Drumm, and Michael W. Nachman, "Ecological Genetics of Adaptive Color Polymorphism in Pocket Mice: Geographic Variation in Selected and Neutral Genes," Evolution 58(6), 2004: 1329-41. 
-Refer to the figure above. In their investigation of natural selection on Mc1r alleles (the gene that determines coat color) in Arizona pocket mice, Hoekstra et al. determined the frequency of the D and d alleles in each population. They also determined the frequency of alleles for two neutral mitochondrial DNA genes (genes that do not affect and are not linked to coat color). Why did the researchers include the mitochondrial DNA genes as part of their experimental design?
A) Allele change for the neutral mitochondrial genes serves as an experimental group and gives information on any general background genetic difference among these populations. 
B) Allele change for the neutral mitochondrial genes serves as a control and determines coat-color differences among these populations. 
C) Allele change for the neutral mitochondrial genes serves as an experimental group and gives information on coat-color differences among these populations. 
D) Allele change for the neutral mitochondrial genes serves as a control and gives information on any general background genetic difference among these populations. 
E) None of the above answers applies.

Quizplus · Accepted Answer

The researchers included the neutral mitochondrial DNA genes as a control to determine general background genetic differences among the populations. Since these genes do not affect coat color and are not linked to the Mc1r gene, changes in their allele frequency are not expected to be influenced by natural selection for coat color. By comparing the pattern of allele frequency changes for the Mc1r gene with that of the mitochondrial genes, the researchers can better determine if any observed differences in coat color are due to natural selection or simply reflect underlying genetic differences among the populations.

The Following Question(s) Are Based on Information in Hopi E