IDENTIFICATION OF TRANSGENIC MICE BY PCR ANALYSIS OF SALIVA

As an alternative to surgically obtaining samples (e.g., tail or tissu e biopsy, toe dock, or blood sampling) from weanling mice to screen fo r transgene integration or other genetic monitoring procedures, we off er a simpler, nonsurgical method. A small amount of saliva, obtained f rom weanling mice by oral wash using a plastic pipet tip, contains eno ugh oral epithelial cells and lymphocytes to yield sufficient DNA for nested primer polymerase chain reaction (PCR) analysis. The procedure can be repeated many times with minimal stress to the animal, in contr ast to tissue biopsy procedures such as tail cutting. Sample analysis is rapid and straightforward; saliva is applied to sample collection p aper and then purified using a solid phase DNA purification system. Th e paper, containing purified DNA, is added directly to PCR cocktail fo r the first round of amplification. For weanling mice, in the second r ound of amplification, a small amount of product from the first round is removed and added to PCR cocktail containing the second set of prim ers. With adult mice, an adequate volume of saliva may be obtained (de pendent upon the sensitivity of the particular reaction) to eliminate the need for second-round amplification with nested primers, This tech nique is reliable, does not require organic solvents, and is more huma ne than protocols currently in use. Furthermore, this technique could replace hundreds of thousands of surgical biopsies on rodents annually , which are performed for both transgene determination and genetic mon itoring procedures.