Institutional Animal Care and Use Committee
Mouse Tail Biopsy Policy
I. General


Tissue for genetic analysis of mice may be obtained by tail biopsy (tail snip) when
scientifically justified and approved by the IACUC.
The following guidelines have been approved by the IACUC for the collection of mouse
tail tissue. Note: tail biopsy must be described in the protocol/amendment and any
proposed deviations from these guidelines require additional scientific justification
II. Background
1. The genotype of a mouse is typically determined by Polymerase Chain Reaction (PCR)
or Southern Blot analysis.
 PCR analysis requires a minimal amount of tissue which can be obtained from tail
biopsy. PCR provides genotyping results quickly and cheaply allowing for efficient
colony management.
 Southern Blot analysis requires larger amounts of DNA which is typically obtained
by the excision of the distal tail.
2. The tail is composed of bone, cartilage, blood vessels, nerves and skin. The extent of
mature vertebrae is related to the age of animals and the location along the length of the
tail. A tail biopsy (2-5 mm at the distal end of the tail) that severs coccygeal vertebrae
prior to completion of mineralization, which occurs when the mouse reaches 3 weeks of
age, causes only minimal pain.
 Tail amputation in mice >3 weeks of age may be a painful procedure with the
potential to produce significant hemorrhage and will require anesthesia or analgesics,
as well as, a scientific justification supported by a literature search for alternatives
which are less invasive and/or painful.
 A mouse’s tail is important physiologically and behaviorally. Minimizing the amount
of tail tissue removed will benefit the animal and its use in research.
Mouse Tail Biopsy Policy
Version 2, 7/10
1
III. Procedure
1. Limit the amount of tail to be amputated to 2-5 mm; 2 mm would be preferable and will
minimize cutting bone. If an additional testing is anticipated, section the original tissue
and freeze a segment. A second biopsy is permissible but must be done under anesthesia
(see #5).
2. Gently restrain the mouse.
3. Obtain tail biopsies, using clean procedures, by cutting the tip of the tail perpendicular to
the long axis with very sharp scissors. Alternatively, use a scalpel or razor blade.
4. Assure hemostasis. In mice <3 weeks, hemostasis is easily achieved by light, direct
digital pressure around the tip of the tail. When necessary, hemorrhage can be controlled
by cautery; a medical-grade, non-toxic, styptic powder (Kwik Stop®) or surgical
adhesives. Consult the veterinarians if problems with hemostasis are encountered or
expected (e.g., mutant mice with clotting disorders).
5. If required, use a short acting inhalant anesthetic, such as Isoflurane: an open-drop
technique, conducted in a fume hood while avoiding direct contact with the animal,
would be acceptable. Closely monitor the animal’s recovery from anesthesia, which
should be transient, and avoid co-housing sedated and active animals.
References




Arras, M, Rettich, A, Seifert, B, Käsermann, HP, & Rűlicke, T (2007). Should laboratory
mice be anaesthetized for tail biopsy? Laboratory Animals. 41, 30-45.
Cinelli, P, Rettich, A, Seifert, B, Bűrki, K, & Arras, M (2007). Comparative analysis and
physiological impact of different tissue biopsy methodologies used for the genotyping of
laboratory mice. Laboratory Animals. 41, 174-184.
Hankenson, C, Garzel, L, Fischer, D, Nolan, B, & Hankenson, K (2008). Evaluation of
Tail Biopsy Collection in Laboratory Mice (Mus musculus): Vertebral Ossification, DNA
Quantity, and Acute Behavioral Responses. Journal of the American Association for
Laboratory Animal Science. 47 (6), 10-18.
NRC (National Research Council), Institute of Laboratory Animal Resources,
Commission on Life Sciences. 1996. Guide for the Care and Use of Laboratory Animals,
Washington D.C., National Academy Press.
Mouse Tail Biopsy Policy
Version 2, 7/10
2