Validation of the Short Amplicon Multiplex Q8 Including the German DNA Database Systems*

Abstract: We have developed a concept to enable the analyzing of degraded stains with limited DNA template quantity. Therefore we have constructed a short tandem repeat (STR) multiplex including the German DNA database systems (Q8). The amplicon lengths are smaller than 280 bp. For the validation of Q8 over 50 degraded samples were investigated. Amplifications were performed with “low copy number” PCR, the number of PCR cycles was increased to 33 and the reaction volume was decreased to 12.5 μL. Compared with the MPX2 and Nonaplex kit, the average success rate was increased using the Q8 kit by approximately 20% and 30%, respectively. The efficiency of a sensitive STR multiplex with reduced amplicon lengths was confirmed in comparing the success rates of Q8 for typing degraded samples and samples with limited amount of DNA template while partial profiles were observed with the majority of the samples using commercially available kits.     

ABO genotyping by duplex amplification and oligonucleotide arrays assay

Objective

Research on the application feasibility of ABO genotyping for forensic identification by oligonucleotide arrays assay.

Methods

Oligonucleotide microarrays which detect three different SNPs in exon 6 and exon 7 for ABO genotyping were used. After hybridization wash, the arrays were scanned and fluorescence intensities were analyzed using microarray population studies on ABO was carried out in a sample of 115 unrelated Chinese Han individuals oligonucleotide arrays for genotype detection. The method was also applied to cases.

Results

Technique could identify six genotypes of ABO system and the results of GeneChip analyses confirmed by PCR–RFLP. According to the results of population studies, no significant deviations Hardy–Weinberg equilibrium could be found. The observed heterozygosity (H-obs) was 0.591. Expected heterozygosity (H-exp) was 0.616. The polymorphic information content (PIC) was the average exclusion probability in paternity testing for duos (PE (1)) was 0.188. The average exclusion probability in paternity testing for trios (PE(2)) was 0.344. The discrimination power 0.777.

Conclusion

The data and case application demonstrated that ABO typing by oligonucleotide probe arrays was a useful technique for paternity testing and individual identification.     

Observation of tri-allelic patterns in autosomal STRs during routine casework

We report three cases of tri-allelic patterns observed during routine forensic casework on 5964 Belgian residents. These individuals had been typed for the following 15 autosomal STRs: CSF1PO, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, vWA, FGA, TH01, TPOX, D2S1338 and D19S433.The first example of a tri-allelic pattern had the genotype 13;15;16 for the D8S1179 locus. In the second observation there was 16;21;22 pattern for the D18S51 locus. The third case had the alleles 10;11;13 also for D18S51.All cases belonged to the Type I tri-allelic pattern, with three uneven peaks, the sum of the heights of both smaller peaks equalling the height of the tallest peak.Three cases in 5964 typed individuals is a frequency for tri-allelic patterns in autosomal STRs of 0.05%.     

Sexual assault cases related to unknown perpetrator: Almost 50% of the analyzed cases corresponded to serial offenders

As a collaborative effort in solving sexual assault cases where there is no suspect, the DNA profiles associated with 273 cases were analyzed. Such cases were submitted from different Criminal Investigation Units belonging to eight judicial departments of Buenos Aires Province. A single NN male profile was recovered from the evidences by differential lysis with DNA IQ System (Promega) and typing with IdentiFiler kit. Comparative analysis of the compiled DNA profiles showed that in 45% of the cases the evidence DNA profile matched in at least two unrelated cases. Associations between groups of unsolved cases provided a valuable tool in aiding law enforcement investigations.     

Developmental validation of a Cannabis sativa STR multiplex system for forensic analysis

A developmental validation study based on recommendations of the Scientific Working Group on DNA Analysis Methods (SWGDAM) was conducted on a multiplex system of 10 Cannabis sativa short tandem repeat loci. Amplification of the loci in four multiplex reactions was tested across DNA from dried root, stem, and leaf sources, and DNA from fresh, frozen, and dried leaf tissue with a template DNA range of 10.0-0.01 ng. The loci were amplified and scored consistently for all DNA sources when DNA template was in the range of 10.0-1.0 ng. Some allelic dropout and PCR failure occurred in reactions with lower template DNA amounts. Overall, amplification was best using 10.0 ng of template DNA from dried leaf tissue indicating that this is the optimal source material. Cross species amplification was observed in Humulus lupulus for three loci but there was no allelic overlap. This is the first study following SWGDAM validation guidelines to validate short tandem repeat markers for forensic use in plants.     

Characterization of 26 miniSTR loci for improved analysis of degraded DNA samples

An additional 20 novel mini-short tandem repeat (miniSTR) loci have been developed and characterized beyond the six previously developed by our laboratory for a total of 26 non-CODIS miniSTR markers. These new markers produce short PCR products in the target range of 50-150 base pairs (bp) by moving the primer sequences as close as possible-often directly next to the identified repeat region. These candidate loci were initially screened based on their small amplicon sizes and locations on chromosomes currently unoccupied by the 13 CODIS STR loci or at least 50 Mb away from them on the same chromosome. They were sequenced and evaluated across more than 600 samples, and their population statistics were determined. The heterozygosities of the new loci were compared with those of the 13 CODIS loci and all were found to be comparable. Only five of the new loci had lower values than the CODIS loci; however, all of these were much smaller in size. This data suggests that these 26 miniSTR loci will serve as useful complements to the CODIS loci to aid in the forensic analysis of degraded DNA, as well as missing persons work and parentage testing with limited next-of-kin reference samples.     

DNA分型实验室管理应重视的几个问题

1985年Gill等第一次报导将DNA指纹图用于个体讽别并获得成功后，DNA分型技术在个体识别和亲子鉴定中的应用潜力开始为法医界所注目【'］．随着该项技术的日益完善，它极大地提高了生物学检材（血液，血痕，精斑，混合斑，毛发和指甲等）在法医物证学鉴定过程中的价值，并广泛应用于法医鉴定实践中．同时，法医界又面临着这样一个问题：如何对有关的DNA分型实验室进行管理监督，以保证其能更好地为司法实践服务．本文从DNA分型实验室人员设置和要求，DNA分型技术标准化以及与传统血型血清学的关系等方面并结合国外进展作如下探讨．ID…     

不同分型方法的STR分型差异

目的调查不同的STR分型系统之间分型的一致性。方法 10 0例不同个体的DNA样本分别用单位点聚丙烯酰胺凝胶银染法和PowerPlex16System试剂盒对 13个法医学常用STR位点进行基因分型 ,并比较两种不同分型系统间的分型结果。结果 1例样本在D8S1179位点出现了分型不一致的结果 :银染法的基因型为 12 / 14 ,而用PowerPlex16System试剂盒的分型则为 12 / 15。结论不同的STR分型系统可导致不同的基因分型     

HLA—A基因座分步PCR—SSP分型研究

目的使HLA基因分型能应用于法医常见检材的个人识别。方法 建立检测HLA—A基因座的分步PCR—SSP方法。先用一对HLA—A基因座特异的引物作第一次扩增,以所得产物为模板,分别用对HLA—A30、A31、A33特异的3对引物作第二次扩增,二次扩增的产物经电泳判型。结果 1130例血清分型为HLA—A30、A31、A33的血痕,其PCR—SSP分型和血清分型的不符合率为29％;室温保存2年的精斑、唾液斑,保存18年的血痕第一次扩增均获得满意的结果。结论法医亲子鉴定和个人识别宜用基因分型替代血清分型。HLA—A基因座分步PCR—SSP基因分型适用于法医检材。