Abstract: Objective To establish an accurate, simple, quick, specific and sensitive method for species identification by amplifying 12S rRNA gene with the same reaction system. Methods Based on the downloaded 12S rRNA gene sequences of eleven species (human, chicken, duck, goose, pig, rabbit, rat, sheep, bull, dog and goat) from GenBank, a pair of universal primers to eleven species and three pairs of specific primers to human,chicken and duck were designed. The amplicons amplified with universal primers were used for internal controls, and the amplicons amplified with specific primers were used as identification of human, chicken and duck. DNA was extracted from various samples including blood stains, fresh or freezing muscles, heat-treated muscles and hairs. Both single DNA of human, chicken or duck and mixed DNA of any two kinds of them were amplified. Results The lengths of universal amplicons were about 400 bp. The lengths of specific amplicons were 163 bp for human, 286 bp for chicken, and 374 bp for duck, respectively. No cross amplification was observed, indicating a high specificity of the specific primers. The identification rate was 100% for human, 99% for chicken, and 100% for duck, respectively. The detection sensitivity ranged from 2.5 pg to 200 pg of DNA concentration depending on species, even in mixtures of different species DNA without interference. Conclusion The method established could identify different species under the same reaction system .

Key words: forensic biology, species identification, 12S rRNA gene, biomaterial