[Analysis of the multi-amplified 5 STR loci and their allelic distribution in both Han populations in Chengdu City and Yunnan province].

Objective: To illuminate the multi-amplified 5 STR loci and their allelic distribution in Hans by means of STR-DNA typing with improved efficiency and decreased cost.

Methods: We have established an allelic ladder of D7S820, D13S317, D5S818, D3S1358 and Amelogenin loci via the cloning techniques. With this homemade allelic ladder, we established successfully a multiplexing polymerase chain reaction (PCR) method, followed by denaturing polyacrylamide gel electrophoresis (PAGE) and silver staining. DNA samples collected from 130 unrelated Han individuals in Yunnan and Chengdu were analyzed. The non-overlapping of the allelic fragments of the five loci allowed the detection to be accomplished successfully.

Results: No difference of the genotyping results of the single locus amplification and multiplexing was observed. The genotype distributions of 4 STR were in accordance with the Hardy-Weinberg equilibrium. 7, 7, 8 and 8 alleles of D7S820, D13S317, D5S818, and D3S1358 loci were observed in Yunnan Han population, as well as 8, 7, 8 and 7 alleles in Chengdu Han population respectively. No significant difference in the allele distribution of these loci was seen between these two Han populations.

Conclusion: This multiplexing system with home-made allelic ladder has a high combined discrimination power and exclusion power. It is a valuable tool in forensic science practice.