A total of 100 EDTA-blood samples were obtained from unrelated individuals of Chinese Han ethnic group in Chengdu of China. DNA was extracted by utilizing the Chelex-100 method as described by Walsh et al. (1). The allelic variation at three STR loci named as D12S2080, D16S2619 and D9S1119 were analyzed by PCR amplification whose respective conditions can be accessed at Nucleotide Database updated by NCBI (http://www.ncbi.nlm.nih.gov), however, their annealing temperatures do not totally amount to those recommended by Database. The details of PCR conditions are described in Table 1. The volume of PCR reaction for each locus was 20 µL containing 2-10 ng DNA, 1 × Taq buffer, 1.5 mM MgCl2, 200 µM each dNTP (Pharmacia Biotech, Sweden), 2.0 U Taq polymerase and 0.3 µM each primer. PCR amplifications were carried out in a GeneAmp PCR System 9600 (Perkin-Elmer).The respective primers of these three loci are described in Table 2.