NON-INVASIVE SAMPLING METHODS FOR GENOTYPING: IMPROVEMENTS TOWARDS THE 4R PRINCIPLE

Abstract

Genetically modified mice are usually genotyped using invasive ear or tail biopsies. In accordance with the 4R principle (Replacement, Reduction, Refinement and Responsibility) we have developed non-invasive sampling methods to prevent stress and pain for mice. DNA could be extracted from oral swabs and hair follicles using conventional PCR and real-time PCR. Signals could be detected up to 25 days after sampling, if the swabs were shipped and stored at +4°C. In a pilot study, oral swabs, hair and biopsies were compared, showing consistent genotyping results in all three sampling methods with hair being more susceptible to contamination. Oral swab and hair follicle sampling provide an alternative that can be used for large-scale routine genotyping, especially if no invasive biopsy is allowed (e.g., animals with ear tags or toe tattoos) or no second biopsy is possible.