In a separate study, 76 rock pocket mice were collected from four different, widely separated areas of dark lava rock. one collecting site was in arizona. the other three were in new mexico. dr. nachman and colleagues observed no significant differences in the color of the rocks in the four locations sampled. however, the dark-colored mice from the three new mexico locations were slightly darker than the dark-colored mice from the arizona population. the entire mc1r gene was sequenced in all 76 of the mice collected. the mutations responsible for the dark fur color in the arizona mice were absent from the three different populations of new mexico mice. no mc1r mutations were associated with dark fur color in the new mexico populations. these findings suggest that adaptive dark coloration has occurred at least twice in the rock pocket mouse and that these similar phenotypic changes have different genetic bases. how does this study support the concept that natural selection is not random?