Mutant sewer rats spreading through major US cities as scientists discover disturbing DNA changes

Scientists have uncovered a disturbing change in both mice and rats infesting America's biggest cities, making the rodents harder to kill than ever before. Researchers at Rutgers University in New Jersey found the vast majority of smaller house mice and larger brown rats in New York, New Jersey, Pennsylvania and Washington DC have genetically mutated to become more resilient to poison. Specifically, five out of every six rodents tested displayed at least one mutation in the Vkorc1 gene, which has been found to affect how well the poisons work. This study of nearly 300 house mice and brown rats also...