摘要
Objective To investigate the application value of the MHSeqTyper47 kit in kinship identification.Methods Multiplexed amplification and library preparation were performed for DNA samples from 113 related individuals by using the MHSeqTyper47 kit.The libraries were sequenced on a MiSeq FGx sequencer,and the data were analyzed using MHTyper for microhaplotype genotyping.The kinship indexes were calculated to evaluate the application efficiency of this kit in kinship identification and compared with those of the GlobalFilerTM kit.Results For the MHSeqTyper47 kit,the CPI values in trio identification were 1.43× 1011～6.15×1018.The CPI values in duo identification were 1.02× 105～1.53× 1013.The CFSI values in full sibling identification were 7.73×101～2.59×1016.Trios,duos and full siblings could be completely distinguished from unrelated pairs.The combined efficiency of these two kits in 2nd-degree kinship identification was 0.466 2.Conclusion The application value of MHSeqTyper47 kit is relatively higher in the identification of lst-degree kinships.If jointly used with the GlobalFilerrM kit,2nd-degree kinship identification could be achieved in some cases.
摘要
Objective To establish and forensically verify a 42 microhaplotypes(mircohaps,MHs)mul-tiplex assay system based on next-generation sequencing(NGS),and to explore the application value of this system in the practice of forensic genetics.Methods A total of 42 highly polymorphic MHs were selected from previous studies,and sequenced by the MiSeq FGxTM platform to verify the repeata-bility,sensitivity,specificity,stability,and mixture analysis ability of the detection system.Through population genetic investigation of 102 unrelated Chinese Han individuals in Liyang City,Jiangsu Province,China,the application value of this system in forensic genetics was evaluated.Results The sequencing repeatability of the 42-plex MHs assay was 100%and the sensitivity was as low as 0.062 5 ng.The system had the ability to withstand the interference of indigo(≤2 500 ng/μL),humic acid(≤9 ng/μL),hemoglobin(≤20 μmol),and urea(≤200 ng/μL)and to detect mixtures of 2 people(1∶19),3 people(1∶1∶9)and 4 people(1∶1∶1∶9).Based on 102 individual data,the combined power of discrimination and the combined power of exclusion were 1-3.45×10-30 and 1-3.77×10-11,respectively,and the average effect value of alleles was 2.899.Conclusion The 42-plex MHs assay was successfully established in this study and this system has high repeatability and sensitivity,good anti-jamming ability and mixture analysis ability.The 42 MHs are highly polymorphism and have good application value in individual identification and paternity testing.
摘要
ObjectiveTo investigate the genetic polymorphism and structure of 47 autosomal microhaplotypes in the Han population in Changshu City, Jiangsu Province, and to evaluate the forensic efficiencies and forensic parameters. MethodsThe DNA library of unrelated individual samples was prepared according to MHSeqTyper47 kit manual and sequenced on the MiSeq FGx platform. Microhaplotype genotyping and sequencing depth statistics were processed using MHTyper. The genetic information of samples was then evaluated. The fixation index and genetic distance between the Jiangsu Changshu population and the reference populations in the 1000 Genomes Project phase 3 (1KG) were calculated, and forensic parameters were evaluated. ResultsThe fixation index and genetic distance between the Han population in Changshu, Jiangsu, and the CHB (Han Chinese in Beijing, China) reference population in 1KG were the lowest. The effective allele number (Ae) of each locus is also the closest between the two populations. The combined matching probability (CMP) of the Changshu Han population is close to the 5 populations of the East Asian reference super-population in 1KG, which is 1.25×10-36, and the combined probability of exclusion reached 0.999 999 999 964 1. ConclusionThis study reported the genetic polymorphism and allele frequency of 47 microhaplotypes in a Han population in Changshu City, Jiangsu Province. This information provides a data basis for 47 microhaplotypes in forensic applications. In addition, the polymorphism differences between the 1KG reference population and the Han population in Changshu, Jiangsu were compared, and the genetic structure of 47 microhaplotypes in the Han population in Changshu, Jiangsu was revealed. In general, the reference data of the East Asian super-population in 1KG is more in line with the genetic characteristics of Han population in Changshu, Jiangsu.
摘要
OBJECTIVES@#To compare the application value of the likelihood ratio (LR) method and identity by state (IBS) method in the identification involving half sibling relationships, and to provide a reference for the setting of relevant standards for identification of half sibling relationship.@*METHODS@#(1) Based on the same genetic marker combinations, the reliability of computer simulation method was verified by comparing the distributions of cumulated identity by state score (CIBS) and combined full sibling index in actual cases with the distributions in simulated cases. (2) In different numbers of three genetic marker combinations, the simulation of full sibling, half sibling and unrelated individual pairs, each 1 million pairs, was obtained; the CIBS, as well as the corresponding types of cumulative LR parameters, were calculated. (3) The application value of LR method was compared with that of IBS method, by comparing the best system efficiency provided by LR method and IBS method when genetic markers in different amounts and of different types and accuracy were applied to distinguish the above three relational individual pairs. (4) According to the existing simulation data, the minimum number of genetic markers required to distinguish half siblings from the other two relationships using different types of genetic markers was estimated by curve fitting.@*RESULTS@#(1) After the rank sum test, under the premise that the real relationship and the genetic marker combination tested were the same, there was no significant difference between the simulation method and the results obtained in the actual case. (2) In most cases, under the same conditions, the system effectiveness obtained by LR method was greater than that by IBS method. (3) According to the existing data, the number of genetic markers required for full-half siblings and half sibling identification could be obtained by curve fitting when the system effectiveness reached 0.95 or 0.99.@*CONCLUSIONS@#When distinguishing half sibling from full sibling pairs or unrelated pairs, it is recommended to give preference to the LR method, and estimate the required number of markers according to the identification types and the population data, to ensure the identification effect.
Subject(s)
Humans , Siblings , Genetic Markers , Computer Simulation , Irritable Bowel Syndrome/genetics , Reproducibility of Results , Genotype摘要
OBJECTIVES@#To investigate the efficacy of different numbers of microhaplotype (MH) loci and the introduction of different reference samples on the identification of full sibling, half sibling and differentiation between full sibling and half sibling kinships, and to explore the effect of changing mutation rate on sibling testing.@*METHODS@#First, a family map involving three generations was established, and four full sibling identification models, five half sibling identification models and five models distinguishing full and half siblings were constructed for different reference samples introduced. Based on the results of the previous study, two sets of nonbinary SNP-MH containing 34 and 54 loci were selected. Based on the above MH loci, 100 000 pairs of full sibling vs. unrelated individuals, 100 000 pairs of half sibling vs. unrelated individuals and 100 000 pairs of full sibling vs. half sibling were simulated based on the corresponding sibling kinship testing models, and the efficacy of each sibling kinship testing model was analyzed by the likelihood ratio algorithm under different thresholds. The mutant rate of 54 MH loci was changed to analyze the effect of mutation rate on sibling identification.@*RESULTS@#In the same relationship testing model, the systematic efficacy of sibling testing was positively correlated with the number of MH loci detected. With the same number of MH loci, the efficacy of full sibling testing was better than that of uncle or grandfather when the reference sample introduced was a full sibling of A, but there was no significant difference in the identification efficacy of the four reference samples introduced for full sibling and half sibling differentiation testing. In addition, the mutation rate had a slight effect on the efficacy of sibling kinship testing.@*CONCLUSIONS@#Increasing the number of MH loci and introducing reference samples of known relatives can increase the efficacy of full sibling testing, half sibling testing, and differentiation between full and half sibling kinships. The level of mutation rate in sibling testing by likelihood ratio method has a slight but insignificant effect on the efficacy.
Subject(s)
Humans , Siblings , Polymorphism, Single Nucleotide , DNA Fingerprinting/methods摘要
Recently introduced microhaplotype has attracted more attention in forensic field. A microhaplotype is a short segment of DNA (e.g<200bp) contains two or more SNPs. The microhaplotypes showed extremely low mutation rates. The amplicons of alleles are balance to each other and without any stutters. By these advantages, it shows great value for forensic application, such as mixture stains analyzing, ancestor analysis, and kinship analysis. Thus, we aimed to review the development, analytical approach, nomenclature and population characteristic of microhaplotype.