Entomologists and pest-management researchers at Rutgers University in New Jersey had a mystery on their hands. Over the course of several years, many local pest control crews had told them similar horror stories of persistent rodent infestations defying their best efforts. “Pest management professionals often told us that rodent control was becoming more difficult […] even though they applied the effective rodenticides,” Jin-Jia Yu, a postdoctoral fellow with the school’s department of entomology, explained in a press statement. Yu and his colleagues now know why. Detailed genomic analysis of DNA from 147 house mice (Mus musculus domesticus) collected from urban areas across New York, New Jersey, Pennsylvania and Washington, D.C. has discovered that 84% of house mice carry a mutation that helps these pests resist anticoagulant rodenticides. And over a third (35%) of the team’s 143 Norway rat specimens (Rattus norvegicus), all sourced from those same northeastern cities, carried these mutations too—polymorphic alterations to the creatures’ Vkorc1 gene.
Anticoagulants are the most widely used rodent-control compounds in the U.S., favored in part because these slow-acting poisons lessen the likelihood that rat and mouse populations will associate the poison traps with danger and learn to avoid them.
