Genetic survey exposes flaws in widely used mouse models

C57BL/6 mice, such as the one pictured here, are commonly used in animal research. Credit: Dani Maver/Alamy Half of laboratory mice are not what scientists think they are, a genetic analysis of hundreds of strains that are distributed globally for animal research has found. The study, published today in Science 1 , uncovered widespread inconsistencies between the reported names of mouse strains and their actual genetic makeup. The mismatches have the potential to compromise the reproducibility of mouse studies and undermine research conclusions, scientists say. “This study is another wake-up call for biomedical research. If we don’t fully understand the genetics of the mice we’re using, we risk misinterpreting how diseases actually work,” says Daniel Rawle, an immunologist at the QIMR Berghofer research institute in Brisbane, Australia. Rawle has first-hand experience of the trouble that a mislabelled mouse strain can cause. In a 2022 study 2 , he and his colleagues uncovered discrepancies in the genotypes of mice engineered to lack an immune protein called granzyme A. The errors had given researchers the false impression that deletion of the gene encoding granzyme A protected mice from a crippling type of arthritis caused by infection with the chikungunya virus 3 . …