Studies of the genetics of resistance of parathion and malathion in the housefly.

Although considerable research has been made into the genetics of resistance to DDT in the housefly-often with conflicting conclusions being drawn from the results-little has been done on the mode of inheritance of resistance to organophosphorus compounds. The experiments described in this paper were designed to fill this gap.Tests on strains of houseflies resistant to either parathion or malathion and crossed with a normal colony indicated that both types of resistance are inherited through single dominant gene pairs, and tests specially designed to determine whether the genes for parathion resistance and those for malathion resistance lie on the same chromosome suggested that the two types of gene are either alleles or closely linked.