A Study Of Miniplex System With Three MiniSTR And Forensic Application

Objective MiniSTR (mini short tandem repeat) loci were recently interesting for forensic science, because they may successfully analyze degraded DNA specimens from mass disaster or challenging forensic caseworks. The purpose of this work is to study a miniplex system with three miniSTR loci, D10S1248, D14S1434 and D22S1045, and its forensic application.Methods Using the primers set from Coble's, a total of 200 samples from unrelated individuals in Chinese population was tested with the miniSTR loci, D10S1248, D14S1434 and D22S1045. The PCR products were detected by PAGE with silver staining system. Then, we constructed a miniplex analysis system with multiplex amplification of the miniSTR loci, D10S1248, D14S1434 and D22S1045. The products were genotyped by ABI PRISM(?) 310 Genetic Analyzer and the results were analyzed with GeneScan 3.7 and GenoTyper 3.7 software. A series of validation experiments were performed for miniplex01 system under the guidelines of Scientific Working Group on DNA Analysis Methods (SWGDAM) .Result The allele structure and genetic polymorphism at three miniSTR loci were obtained. One new allele was observed in our population sample and named as allele 8 at D10S1248. And different repeat motifs (CTGT)_n (CTAT)_n (CCAT)_ n was observed at D14S1434. Human allele ladders including new alleles had constructed in-house. The combined power of discrimination for the three loci in Chinese population was 0.9988 and the cumulative probability of exclusion was 0.8536. A fluorescent multiplex miniSTR system, including D10S1248, D14S1434 and D22S1045 was developed. The results showed that this system had excellent species specificity, high sensitivity and good reproducibility.Conclusion The miniplex (D10S1248, D14S1434, and D22S1045) has high discrimination power and small amplicons in Chinese population. Our results suggested that these miniSTR makers had different characterization in different ethic groups. The validation study showed that our fluorescent miniplex STR system satisfied the SWGDAM guidelines and it can be applied for forensic casework. The system was proved to be robust and reliable. This makes them valuable markers for forensic identity testing when encountered highly degraded DNA samples.