When multiplex PCR was carried out on the same samples, the set of primers remained in the same specificity, the result of which could be seen in Fig. 2 and Fig. 3. In simplex PCR, DF/DR primers could generate specific fragments of 230 bp for Tarim red deer and reindeer. However, these two fragments disappeared in the multiplex PCR. This is due to the fact that the more efficiently amplified loci negatively influence the yield of the product from the less efficient loci when many specific loci are simultaneously amplified (Henegariu et al., 1997). The electrophoretic pattern clearly showed the absence of cross-reaction. In fact, only the species specific bands were evident.