There are various methods available for collecting tissue or blood for genotyping.
The technique selected must be described in your approved Animal Study Proposal.
Please consult your veterinarian if you need additional assistance in the selection of the technique appropriate
for your research.
Most commonly, genotyping of mice is accomplished by amputating a small portion of the
distal tail. This is best performed when the pup is 10 - 15 days old.
Prior to attempting this procedure, you should become familiar with the NHGRI Guideline 00.2 "Procedures for Tail Biopsy for DNA Analysis and Genotyping in Mice" and you should receive training from your veterinarian.
Five millimeters, or less, of the distal tail is removed for this procedure.
The tail is sprayed with a topical hypothermic prior to collection of tail tissue.
As an alternative to the topical hypothermic, the animal may be anesthetized.
A scalpel or scissors can be used to remove the tissue.
The instruments are sterile at the beginning of the procedure and sanitized with Clidox, Alcide or other appropriate disinfectant between animals.
You must assure that adequate hemostasis has been achieved before returning the animal to its cage.
Surgical glue, silver nitrate or direct pressure with a sterile gauze pad can be used for this purpose.
The tissue removed during ear punching can be used for polymerase chain reaction for rapid screening of mice.
Some transgenic mice are genotyped by blood sampling.
Please refer to the blood collection section of this program for the proper technique for obtaining blood samples.
Other alternatives to tail snipping for genotyping are also available.
These include the analysis of hair, saliva, or feces.
This information is available in the reference section.
Revised 4/6/04 8
- Select the genotyping method appropriate for your research purposes.
- Tail snips should be performed on mice at 10 - 15 days of age.
- A topical hypothermic must be used to numb the tail or the animal must be anesthetized
prior to performing a tail snip.
- Do not remove more than 5 mm of the tail.
- Begin with sterile instruments and sanitize between animals.
- Ensure good hemostasis following the procedure.
- The genotyping method must be described in the Animal Study Proposal.
Source: US National Institutes of Health