IACUC / LARC STANDARD PROCEDURES

COLLECTION OF TISSUES FOR GENOTYPING (Updated May 2007)

Collection of tissues for genotyping is a common procedure when using genetically modified mice. The most common method for gathering tissue is tail-snipping, which if done at weaning (3 weeks of age) does not require anesthesia. Please follow these steps when performing tail snipping:

•  Use clean, sharp scissors
•  Apply pressure to tail after snipping, or use styptic pencil
•  Do not take more than 1-2 mm of tissue if using PCR for genotyping
•  You must use anesthesia if tail-snipping mice older than 3 weeks of age

If ear-punching mice for identification, the section of ear removed by the punch tool should be used for genotyping.

Toe clipping is not a standard procedure and must be justified in the IACUC application form.

Other analytical and confirmatory techniques may require more tissue (1 cm). Anesthesia should be employed for this procedure if the animals are older than 3 weeks of age. Inhalant agents used with a vaporizer are recommended. The smallest possible section of tail needed (not greater than 1 cm), should be removed and adequate homeostasis achieved (pinching tail until bleeding stops).

Please contact LARC veterinarians 476-2204 for assistance.