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Tulane University
Department of Comparative Medicine (DCM)
Standard Operating Procedures (SOPs)
5.2.2
Procedures for Transgene Identification
A.
Purpose/Scope
To describe procedures used to obtain tissue needed for transgene identification in rodents.
Any modifications to this policy must be described and justified in an IACUC protocol
B.
Definitions
 IACUC- Institutional Animal Care and Use Committee
 PCR- Polymerase Chain Reaction
C.
References
 Policy 6.10 Tulane University IACUC Rodent Identification Policy.
 Guide for the Care and Use of Laboratory Animals, National Research Council, National
Academy Press.
 NIH “Guidelines for Toe Clipping of Rodents” revised 6/13/07.
D.
Background
This procedure applies to breeding colony managers, researchers and technicians who collect
tissue samples from mice for transgene identification. PCR techniques may require less tissue
and allow use of auricular flap tissue obtained during the ear punch identification procedure.
Southern Blot and Dot blot testing may require more material and need tissue obtained from tail
or toe snips.
E.
Procedures
Ear Punching: This form of transgene identification involves using an instrument designed for
taking small (0.5-2mm) biopsies from a rodents’ ear. The instrument must be decontaminated
between rodents. The ear of an altricial neonate does not open until at least 10 days of age, so
prior to this age, ear notching requires scientific justification.
Tail Snipping: Tail snips must be less than 0.5 cm in length. Anesthesia is not required in mice
through weaning. Innervation of the tip of the tail is minimal prior to weaning. Tail tip samples
greater than 1cm in length will probably damage the coccygeal vertebrae and will require
anesthesia in mice of any age. Swab the tail with alcohol prior to snipping with a sterile, sharp
instrument such as a scissor or scalpel blade. Apply gentle pressure or apply silver nitrate until
hemostasis is achieved. Anesthesia is required for any tail snipping if animals are weaned.
Blood: Blood is useful for transgene identification when the phenotype is determined in the
peripheral blood cells. Blood can be obtained by laceration of a blood vessel or retro-orbital
sinus and may require anesthesia. All applicable facility SOPs must be followed. Blood cannot
be safely collected from neonatal rodents.
Hair, Feces, Saliva, or Rectal Mucosa Sampling: These techniques generally yield a small
amount of DNA, but may be appropriate when assays are extremely sensitive. Generally these
techniques require plucking hair, collecting freshly passed feces, swabbing the inside of the
mouth or swabbing the rectum. They may require short restraint but are considered non-invasive
and do not require anesthesia.
5.2 Procedures for Transgene Identification
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Approved by: HSC IACUC October 2002
Revision 2 Review: February 2008
Revision 2 approved:
Uptown- April 2008
TNPRC- May 2008
HSC-May 2008
Director, DVSR
Date
IACUC Chair
Date
5.2 Procedures for Transgene Identification
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