A polymerase chain reaction-based method for the identification of DNA samples from common vertebrate species

Polymerase chain reaction (PCR) amplification of vertebrate genomic DNAs using a (CAC)n primer was found to generate species-specific patterns which are resolvable by agarose gel electrophoresis. Of the thirteen species tested (trout, frog, chicken, mouse, rat, cow, dog, African green monkey, chimpanzee, orangutan, gorilla, rhesus macaque, and human), all species showed discrete amplification products ranging in size from 1.0 to 3.2 kbp although trout and frogs had only weak (CAC)n amplification products. Most species had three to six bands except rodents, who had eight bands, and cows, who had a single band at 2.2 kbp. Importantly, within a single species, different unrelated individuals had highly similar amplification band patterns although the relative intensities of the bands varied. This held true even when different unrelated humans of different racial backgrounds were tested. We conclude that this technique is potentially useful for identifying which vertebrate species contributed DNA to a given biological sample (e.g., bloodstains, semen, hair) and that only a very small amount of sample is necessary for the analysis.