Forensic Validation and Application Evaluation of IDentifier DNA Typing Kit (Yan-Huang34).

OBJECTIVES: To investigate the technical performance of IDentifier DNA typing kit (YanHuang34) and evaluate its forensic application value. METHODS: Following the Criterion of Forensic Science Human Fluorescence STR Multiplex Amplification Reagent (GB/T 37226-2018), IDentifier DNA typing kit (YanHuang34) was verified in 11 aspects of species specificity, veracity, sensibility, adaptability, inhibitor tolerance, consistency, balance, reaction condition verification, mixed samples, stability and inter batch consistency. The system efficiency of IDentifier DNA typing kit (YanHuang34) was compared with the PowerPlex® Fusion 6C System, VersaPlex® 27PY System and VeriFilerTM Plus PCR Amplification Kit. The IDentifier DNA typing kit (YanHuang34) was used to detect the swabs of biological samples in daily cases and the STR performances were observed. RESULTS: IDentifier DNA typing kit (YanHuang34) had good species specificity, veracity, adaptability, inhibitor tolerance and balance. The sensibility was up to 0.062 5 ng. It was able to detect different types of samples, degraded samples and inhibitor mixed samples. Complete DNA typing could be obtained for samples with the mixture ratio less than 4∶1. The system efficiency of IDentifier DNA typing kit (YanHuang34) was very high, with TDP up to 1-1.08×10-37, CPEtrio and CPEduo up to 1-5.47×10-14 and 1-6.43×10-9, respectively. For the touched biological samples in actual cases, the effective detection rate was 21.05%. The system efficiency of kinship, single parent and full sibling identifications was effectively improved. CONCLUSIONS: The IDentifier DNA typing kit (YanHuang34) is adaptive to the GB/T 37226-2018 requirements. It can be used for individual identification and paternity identification, and is suitable for application in the field of forensic science.

Molecular investigation of infection sources and transmission chains of brucellosis in Zhejiang, China.

In the present study, a total of 7793 samples from 5 different types of hosts were collected and tested, with a seroprevalence of 2.4% (184/7793). Although the seroprevalence of human and animal brucellosis is relatively low, numbers of human brucellosis cases reported have increased continuously from 2004 to 2018. A total of 118 Brucella strains containing 4 biotypes were obtained, including Brucella melitensis bv.1 (n = 8) and bv.3 (n = 106), Brucella abortus bv.3 (n = 3) and bv.7 (n = 1). Twenty-one shared MLVA-16 genotypes, each composed of 2 to 19 strains obtained from different hosts, suggest the occurrence of a brucellosis outbreak epidemic with multiple source points and laboratory infection events. Moreover, 30 shared MLVA-16 genotypes were observed among 59.6% (68/114) B. melitensis isolates from Zhejiang and strains from other 21 different provinces, especially northern provinces, China. The analysis highlighted the imported nature of the strains from all over the northern provinces with a dominant part from the developed areas of animal husbandry. These data revealed a potential transmission pattern of brucellosis in this region, due to introduced infected sheep leading to a brucellosis outbreak epidemic, and eventually causing multiple laboratory infection events. It is urgent to strengthen the inspection and quarantine of the introduced animals.