The Mc1r gene encodes a protein called melanocortin 1 receptor (MC1R). This receptor plays a role in the coat color of the rock pocket mouse. When the normal Mc1r gene is present, melanocytes, which are melanin-producing skin cells, decrease the production of the dark-colored pigment called eumelanin and increase the production of the light-colored pigment, pheomelanin. The mutated version of the Mc1r gene results in an increase in the production of eumelanin by melanocytes, resulting in the dark coat-color phenotype. a. In the data provided in Step 3 of the procedure, the MC1R protein in the dark rock pocket mouse population from the Pinacate lava flow contains how many mutations?
b. Compare the amino acid data of dark-colored mice from the other three populations to that of the wild-type (light-colored) mice in the Pinacate region. What do you notice?
c. Use the information in the excerpt on page 1 to explain the evolutionary significance of MC1R protein variations in the different mouse populations.