310型遗传分析仪的应用

使用ABI公司ProfilerPlus、Cofiler试剂盒及310型遗传分析仪(以下简称310)检验各类案件2000余起,简化了ABI公司推荐的检验步骤,节约了成本,缩短了检验时间,讨论分析常见问题并提出解决办法,使结果分析更为客观准确.     

Comparison of ethyl glucuronide in hair with phosphatidylethanol in whole blood as post-mortem markers of alcohol abuse

Ethyl glucuronide (EtG) is a direct metabolite of ethanol and has been used as a marker of alcohol abuse in both urine and hair. This study investigated the value of EtG testing in post-mortem hair for diagnostic improvement of alcohol abuse in forensic medicine. Material from 70 consecutive medico-legal autopsies was collected in accordance with the recommendations on ethics by the Swedish National Board of Forensic Medicine. A method for determination of EtG in hair samples was developed using ultra performance liquid chromatography/electrospray tandem mass spectrometry (UPLC/ESI-MS/MS; LOQ, 2.5 pg/mg). The result of the EtG analysis was compared with the findings of phosphatidylethanol (PEth) in femoral whole blood, as measured by high performance liquid chromatography with an evaporative light-scattering detector (HPLC-ELSD; LOQ, 0.22 micromol/l). Evaluation of liver histology and anamnestic evidence of alcohol abuse of the deceased were taken in consideration for the interpretation. Measurable levels of EtG were present in 49 of the 70 autopsy cases whereas PEth was present in 36. Thirty-nine cases had EtG levels above the cutoff limit (> or = 30 pg/mg) compared with 29 for PEth (> or = 0.7 micromol/l). Fifteen cases had EtG as exclusive indicator for alcohol abuse compared with four cases for PEth. These findings suggest that measurements of EtG in hair may provide improved diagnostic information on alcohol abuse, due to a long retrospective time-window for detection and stability of EtG in hair in the decaying cadaver. However, an EtG level below the cutoff does not completely exclude previous alcohol abuse.     

Paternity probability when a relative of the father is an alleged father

When scientists use DNA evidence in court, coancestry effects such as population structure and relatedness are usually ignored. In paternity cases, only if a particular man has the child's paternal allele at a certain locus, can he not be excluded in the paternity dispute. However, it is certainly true that close relatives will be far more likely to have the child's paternal allele than will random members of the reference population. In particular, the probability that the true father's brother has the paternal allele is very much greater than that for any other relationship. In this paper, the authors describe a method for inference in a case where the true father may be a relative of the alleged father. This paper also reports that most current methods overstate the probability that the alleged father is the father.     

河南汉族群体6个STR基因座遗传多态性研究

目的　通过研究 6个STR基因座FGA ,TPOX ,D3S135 8,vWA ,D8S1179,D2 1S11的遗传多态性 ,了解它们在河南汉族人群中的多态分布 ,与其他群体进行比较 ,得出遗传距离 ,并了解它在法医学中的应用价值。　方法　采用多聚酶链式反应扩增这 6个基因座 ,采用非变性聚丙烯酰氨凝胶电泳银染显色分析。　结果　得出这 6个基因座在河南汉族人群中的基因频率 ,并计算得出杂合度、个体识别率、非父排除率 ,与其他群体比较得出进化距离。　结论　这 6个基因座有较高的杂合度 ,并且具有相对遗传稳定性 ,在人群中的分布符合Hardy -Weinberge平衡 ,有较高的法医学价值 ,可以应用于个体识别和亲权鉴定。     

RNA指标在死后人体皮肤组织中稳定性研究

目的探讨多种RNA指标的表达水平在死后人体皮肤组织中的稳定性。方法收集死亡时间(PMI)明确的人体皮肤组织样本10例,提取总RNA,运用实时荧光定量PCR(qRT-PCR)技术检测ACTB、GAPDH、18S、miR-203、5S、1et-7a、RPS29、U6共计8个RNA指标的表达水平。geNorm软件评估各RNA指标表达水平的稳定性,挑选出稳定的内参指标并分析其表达水平与相关因素(年龄、性别、死因)的关系。结果人体皮肤组织中5S、U6和miR-203表达水平最为稳定,其平均表达量与年龄、性别、及死因无关(P0.05)。结论 5S、U6和miR-203可以作为qRT-PCR方法研究PMI的理想内参指标。     

Population genetic data of 38 autosomal InDels in San Basilio de Palenque,the first free town in America

In order to increase the information about Indels, we report allele frequencies and statistical parameters of forensic efficiency obtained typing a sample of 114 unrelated healthy individuals living in San Basilio de Palenque – Colombia using a panel of 38 autosomal InDels. No significant deviations from Hardy–Weinberg expectations were found except in the marker rs10629077 (p = 0.0002). The present database will be useful for forensic and paternity purposes for the region studied. Moreover, these additional markers can help forensic laboratories to solve parentage testing as well as to improve the analysis of degraded DNA samples.     

Tri-allelic SNP markers enable analysis of mixed and degraded DNA samples

For the analysis of degraded DNA in disaster victim identification (DVI) and criminal investigations, single nucleotide polymorphisms (SNPs) have been recognized as promising markers mainly because they can be analyzed in short sized amplicons. Most SNPs are bi-allelic and are thereby ineffective to detect mixtures, which may lead to incorrect genotyping. We developed an algorithm to find non-binary (i.e. tri-allelic or tetra-allelic) SNPs in the NCBI dbSNP database. We selected 31 potential tri-allelic SNPs with a minor allele frequency of at least 10%. The tri-allelic nature was confirmed for 15 SNPs residing on 14 different chromosomes. Multiplex SNaPshot™ assays were developed, and the allele frequencies of 16 SNPs were determined among 153 Dutch and 111 Netherlands Antilles reference samples. Using these multiplex SNP assays, the presence of a mixture of two DNA samples in a ratio up to 1:8 could be recognized reliably. Furthermore, we compared the genotyping efficiency of the tri-allelic SNP markers and short tandem repeat (STR) markers by analyzing artificially degraded DNA and DNA from 30 approximately 500-year-old bone and molar samples. In both types of degraded DNA samples, the larger sized STR amplicons failed to amplify whereas the tri-allelic SNP markers still provided valuable information. In conclusion, tri-allelic SNP markers are suited for the analysis of degraded DNA and enable the detection of a second DNA source in a sample.     

Simulating transfer and persistence of a chemical marker powder for Lycopodium clavatum spores

In this research a chemical marker powder, based on Lycopodium clavatum spores, was studied to determine its transfer and persistence on a T-shirt. Such chemical marker powders are used to provide evidence that a person has handled a covertly marked object, such as a drug package. The powder was found to transfer readily between a marked item and the person handling it. The powder was found to persist on a T-shirt for up to 13 h; however, there was only a very small amount of powder remaining at this time. The rate of loss of the L. clavatum spores was found to follow a decay curve. The largest decrease in spores from the T-shirt was seen in the first 2 h after the marked item had been handled.     

Big genetic data and its big data protection challenges

The use of various forms of big data have revolutionised scientific research. This includes research in the field of genetics in areas ranging from medical research to anthropology. Developments in this area have inter alia been characterised by the ability to sequence genome wide sequences (GWS) cheaply, the ability to share and combine with other forms of complimentary data and ever more powerful processing techniques that have become possible given tremendous increases in computing power. Given that many if not most of these techniques will make use of personal data it is necessary to take into account data protection law. This article looks at challenges for researchers that will be presented by the EU's General Data Protection Regulation, which will be in effect from May 2018. The very nature of research with big data in general and genetic data in particular means that in many instances compliance will be onerous, whilst in others it may even be difficult to envisage how compliance may be possible. Compliance concerns include issues relating to ‘purpose limitation’, ‘data minimisation’ and ‘storage limitation’. Other requirements, including the need to facilitate data subject rights and potentially conduct a Data Protection Impact Assessment (DPIA) may provide further complications for researchers. Further critical issues to consider include the choice of legal base: whether to opt for what is often seen as the ‘default option’ (i.e. consent) or to process under the so called ‘scientific research exception’. Each presents its own challenges (including the likely need to gain ethical approval) and opportunities that will have to be considered according to the particular context in question.     

武汉汉族人群STR基因座D3S1358、D13S317、D12S391的多态性研究

目的　调查中国武汉地区汉族人群STR基因座—D3S1 358、D1 3S31 7、D1 2S391基因频率分布和群体遗传数据。方法　从 2 0 8个汉族无关个体收集血液标本 ,应用PCR技术及聚丙烯酰胺凝胶垂直板电泳对D3S1 358、D1 3S31 7和D1 2S391基因座分型。结果　D3S1 358检出 7个等位基因和 4 1个基因型。三基因座基因型分布符合Hardy-Weinberg平衡。观察 2 31次减数分裂均未发现突变基因。另外 ,调查结果计算显示D3S1 358、D1 3S31 7和D1 2S391基因座的杂合度 (H)分别为 0 70 98、 0 80 56和 0 84 0 0 ;三个人识别能力 (DP)分别为 0 851 6、 0 9332和 0 952 3;非父排除率 ( pE)分别为 0 4 463、 0 60 1 6和 0 681 8。结论　D3S1 358、D1 3S31 7和D1 2S391基因座在群体遗传学研究和法医学亲子鉴定及个人识别中具有较高实用价值