The genus is affected by Wolbachia bacteria and it has been suggested that horizontal gene transfer may have led to the difficulty in separating species of Protocalliphora through DNA fingerprinting, with several species possessing identical mtDNA Cytochrome oxidase I sequences.
These target genes encode proteins such as cyclooxygenase, NO synthase, phospholipase A2, tumor necrosis factor, transforming growth factor beta, ICAM-1, and a number of other pro-inflammatory proteins.