Mutant rats resist warfarin

A new series of mutations have been discovered that allow rats to resist the effects of the popular poison warfarin. Research published in the open access journal BMC Genetics describes eighteen new genetic changes found in rats from four continents.

Simone Rost from the University of Wuerzburg, Germany, and an international team of researchers studied more than 250 rats and mice from anticoagulant-exposed areas in Europe, East Asia, South Africa and the Americas. Rost explained that, "Resistance against warfarin-like compounds has been reported in rodent populations from many countries around the world and poses a considerable problem for efficacy of pest control."

Warfarin and related compounds are derivatives of the plant toxin coumarin. They prevent blood coagulation by repressing the enzyme vitamin-K reductase (VKOR). Rost and colleagues studied VKORC1, the gene responsible for a key component of the VKOR multiprotein complex. According to the authors, "Mutations in VKORC1 may cause a heritable resistance to warfarin, possibly by preventing coumarin derivatives from interfering with the activity of the reductase enzyme".