ADI1 and malaria: Thus, even though APL1 and interacting genes may be important in defense against malaria parasites, we cannot be certain the evolutionary history of these genes results from selective pressure imposed by Plasmodium. Given the ecological differences between M and S form mosquitoes, it is quite likely that distinct pathogens, potentially including pathogens of the larval life stage, could impose distinct selective pressures on the M and S forms, potentially explaining the difference between forms in the evolutionary trajectory of the APL1 genes.