Two populations of fruit flies diverged 10,000 years ago. In the first populations, a gene has a mutation rate of 0.002 mutations per generation. In the second population, a gene has a mutation rate of 0.0004 mutations per generation. Generations in each population are 1 yr.
When two species of organisms have genetically diverged, the number of mutations distinguishing particular genes is the sum of the number in one organism and the number in the other. For the above case, find the expected number of mutations distinguishing the species.