Iconic Peppered Moth - gene mutation found

I'm trying to think through Faith's built in genes vs. mutations.How precisely are genes located on the chromosome? If Faith is right, each variation of a gene would have to be in a slightly different location with surrounding alternative genes degraded to "junk dna"If the change is due to mutation, wouldn't the gene be in the same exact location with other functioning genes surrounding it?

I don't think that would work in your idea of super gene. Since black is dominate, all the mice be black until the black gene was mutated to junk dna. So in order for there to be light mice to survive on the desert sand, they would have already lost the black gene.Then there would not have been a black gene for the lava mice to use.