In a lab experiment we examined the evolutionary effects effects of genetic stress: a harmful recessive mutation (nub E and nub X)that was experimentally introduced into a population of flies hundreds of years ago. The goals were to assess the impact of nub on juvenile fitness, the impact of nub on adult fitness and to assess the degree of compensatory evolution in the evolved wingless population. We compared two populations with one another (nub E and nub X) and with a base population for reference. What could be wrong with this experiment? Could other genetic mechanisms played a role in the differentiation of these populations? If so, how could this have been made a better experiment?