Traditional genotyping requires the use of DNA isolated from harvesting fresh tissue samples from laboratory animals-a procedure known to cause pain and stress to the animal. For most research institutions, it is an ethical and legal obligation to reduce or eliminate pain and distress in research animals. First published in 1959, Russel and Burch’s The Principles of Humane Experimental Technique describes the 3Rs of a new applied science with the intent to improve the treatment of laboratory animals. These terms: replacement, reduction and refinement are the key tenets to guide minimizing animal pain and distress in biomedical research.
Refinement, as defined in the Principles is concerned not only with minimizing distress during experiments, but with maximizing comfort and wellbeing of the animals in husbandry. Eliminating the need for painful tissue excision for the purposes of genotyping is one way to meet this ethical obligation when working with research animals. To this end, we have expanded our genotyping platform to include the ability to screen DNAs isolated from client submitted buccal swabs, a non-invasive procedure that can allow for re-sampling of mice in the absence of painful tissue excision.
- Ability to re-confirm genotypes of a mating without the need for anesthesia or analgesia.
- Ability to test for recombination events, at multiple timepoints, when using ubiquitously expressed conditional systems, without having to excise multiple tissue samples.
- Minimize pain and distress in laboratory animals and comply with institutional IACUC regulations.
- Reduce time and costs associated with obtaining multiple tissue specimens.
- Refer to your institution’s IACUC protocols concerning animal handling and sample collection prior to proceeding.
- Use only DNA-free sterile Puritan™ PurFlock Ultra 6″ Sterile Ultrafine Flock Swab w/Polystyrene Handle, 100mm Breakpoint (Catalog 3317-U, available from Harmony Lab and Safety Supplies), for buccal mucosa swab samples taken from mouse cheeks.
- Swabs containing blood may inhibit PCR results and are not acceptable for genotyping.
- Swabs should be shipped in either tubes or covered deep well plates (VWR, Cat 10011-940) and packaged in a way that preserves individual swab identity and prevents cross contamination.
- For the best DNA yield it is preferred that samples be shipped overnight.
- Open the outer packaging of the swab. Preparing swabs by placing them in the appropriate 1.5 mL tubes or well in a deep well plate can avoid confusion between swabs.
- Hold the mouse securely and insert the brush-like end of the swab into its mouth. Rub the swab on its inner cheek by rotating the swab three times around its axis, taking care to avoid any facial veins or the tongue. This step is critical to ensure sufficient material for downstream DNA extraction. Note that you are collecting cell material from mucosa and not just a saliva sample.
- Remove the swab from the mouse’s mouth and place the brush-like end of the swab into deep well plate. Release the distal part by cutting with scissors.
- Cover plate securely.