DNA甲基化在法医DNA分析中的应用

表观遗传学在生命的发生、发展过程中起着十分重要的作用。DNA甲基化作为表观遗传的一个重要方面,不仅参与多种基因的表达调控,与机体的发育、肿瘤发生等密切相关,而且具有可遗传性、相对稳定性、亲缘特异性、基因组中含量丰富等特点,已证实适用于法医DNA分析。本文对近年来DNA甲基化在印迹基因、同卵双生子鉴定、年龄、性别推断方面的研究与应用进行回顾与综述,以期为在法医学及相关领域中应用提供参考。     

To destroy snail mail: Is this the sole solution for anthrax contaminated letters?

Suspicious packages, strange addresses on envelopes and/or the presence of particular powders: these are the most popular aspects of letters containing Bacillus anthracis. Since the World Trade Center tragedy, alarmism about chemical or biological attacks is always in force. The Italian Ministry of Foreign Affairs introduced new procedures to be followed in case suspected anthrax letters are identified (Ministry of Health PROT. 400.3/120.33/4786 of 23/10/2001). Scientists have to collect samples from surfaces and infectious waste have to be placed in autoclavable bags for decontamination. After the sterilization, mails and packages are burnt thus eliminating every biological trace present on their surface. As a matter of fact, after sterilization, DNA is still present and can be analyzed for forensic purposes: for this reason, here we report on the importance of preserving sterilized substrates. We recreated false infected mails with biological traces on their surfaces, sterilized them and, subsequently, we took samples of biological stains and processed them for DNA quantification and typing. We recreate different time conditions consistent with those of the postal service too. Real-Time PCR and DNA typing showed that, even if sterilization destroys the bacillus, human genomic traces still persist and we obtained both complete and partial profiles of samples’ donors. To conclude, the problem of anthrax contaminated letter call for peculiar and standardized procedures; nonetheless, we show that burning evidences after the sterilization process does not appear to be the best solution since there is a loss of biological material which could be decisive for forensic purposes.     

Investigation of the methylation status around parent-of-origin detectable SNPs in imprinted genes

Methylation of CpG dinucleotides was investigated in five regions by bisulphite treatment of gDNA, PCR and cloning/sequencing. The gDNA was prepared from peripheral blood, saliva, semen, nails and hair from the head. In gDNA from peripheral blood, three regions were investigated in 16, 23 and 24 individuals, respectively (Fig. 2). In gDNA from other sources, three or five regions were investigated in five individuals (Fig. 3). In many of the sequenced fragments, all the CpG dinucleotides were either methylated or not, which support the idea that the parental origin of an allele may be determined by the methylation status of the allele. However, the methylation of CpG dinucleotides varies across the fragment in some of the sequenced fragments, especially from semen samples, which indicate that it may be difficult to determine the parental origin from some gDNA sources by restriction-enzyme analysis (DMPA method).     

分子印迹固相萃取技术-液相色谱法测定鱼塘水中2甲4氯苯氧乙酸

目的建立分子印迹固相萃取技术对鱼塘水中2甲4氯苯氧乙酸进行提取和分析的方法。方法以2甲4氯分子印迹聚合物为固相萃取材料,对鱼塘水中2甲4氯进行分离提取,洗脱液直接进行液相色谱分析。结果鱼塘水中MCPA的提取率在80%以上,检出限0.040μg/mL,在0.2μg/mL～2.0μg/mL范围内线性关系良好。结论该方法的准确度和精密度较好,适合实际发生案件的检测分析。     

A generational model of political learning

We propose a mathematical framework for modeling opinion change using large-scale longitudinal data sets. Our framework encompasses two varieties of Bayesian learning theory as well as Mannheim's theory of generational responses to political events. The basic assumptions underlying the model are (1) that historical periods are characterized by shocks to existing political opinions, and (2) that individuals of different ages may attach different weights to those political shocks. Political generations emerge endogenously from these basic assumptions: the political views of identifiable birth cohorts differ, and evolve distinctively through time, due to the interaction of age-specific weights with period-specific shocks. We employ this model to examine generational changes in party identification using survey data from the 1952–2008 American National Election Studies.     

Rapid genomic DNA extraction (RGDE)

Hyperpolymorphic short tandem repetitive DNA sequences, STRs or microsatellites, have become widely used in human identification, particularly in criminal cases and in mass disasters. In such cases the substrates for the analyses may be decomposed as a biological material, a fact that has to be taken into account when choosing the appropriate casework methods. Nowadays expanded windows have been opened to the world especially in the area of genetic and biology science by performance of big projects such as human genome project. In this regard, one of the primary and important steps for all is DNA extraction with high quality and quantity in minimum time from biological material. By using RGDE method, genomic DNA with high quality and quantity can be acquired in the shortest time which has been presented in the world up to now. In this paper we report the evaluation of DNA extraction in this method.     

Genetic Data and the Data Protection Regulation: Anonymity,multiple subjects,sensitivity and a prohibitionary logic regarding genetic data?

Owing to the unique qualities of genetic data, there have been numerous criticisms of the current data protection framework's ability to protect genetic data. It has been suggested that the Directive did not recognise the sensitivity of genetic data and that it ignored a number of legitimate interests in this data (in particular interests which multiple data subjects may have and those which may remain in anonymous data). In 2012, the first results of a reform process of EU data protection law were released. These results included a draft Regulation (to replace the Directive) which introduced a new framework for the protection of genetic data. This Article considers whether the innovative approach to genetic data in the Regulation will provide a more adequate framework for the protection of genetic data. It concludes that the Regulation has rectified the lack of recognition of sensitivity, but still stutters in recognising a number of legitimate interests.     

修枝剪剪切痕迹研究

修枝剪是剪切树木枝干的专用工具,它的结构和剪切原理与普通剪类工具不同。修枝剪剪切树木枝干易形成印压痕迹、线条状痕迹和折压痕迹,这些痕迹受剪切工具和客体的影响会产生一定的变化,其中线条状痕迹、印压痕迹和剪切面的形态可作为判别此类工具的依据。     

分子印迹技术在毒品检测中的应用

分子印迹技术具有优越的识别性和选择性,在毒品检测中具有重要的研究潜力。分子印迹技术应用与打击毒品犯罪相结合,已成为当今法庭科学工作者研究的热点问题。本文阐述了分子印迹技术的基本原理,并对其在固相萃取、吸附分析、化学发光、传感器、色谱分析等毒品检测技术中的应用情况进行了综合概括,并展望了分子印迹技术领域的发展趋势。     

印记基因KCNQ1的遗传多态性及在亲权鉴定中的应用

目的为了调查印记基因KCNQ1的STR位点在中国汉族人群中的遗传多态性，利用亲源印记等位基因（parentally imprinting allele，PIA）分型法确定孩子的等位基因亲代来源，为亲权鉴定提供新的侯选STR位点。方法应用Chelex法提取153例佳木斯地区汉族健康无血缘关系个体DNA，用QIAamp Blood Kit（Qiagen）法提取3个家庭10个个体DNA，PCR扩增，凝胶电泳分型，ABIPRISM^TM 3730XL DNA测序仪测序；甲基化敏感性限制性内切酶消化孩子基因组DNA，PCR扩增，确定孩子等位基因的亲代来源。结果发现在中国佳木斯地区汉族人群中KCNQ1基因的STR有7个等位基因，多态信息含量为0．662，且KCNQ1基因的STR位点呈父源印记。结论印记基因KCNQ1的STR位点有很好的多态性，可为亲权鉴定提供新的侯选遗传标记，其亲源特异性甲基化标记有望应用于单亲鉴定中。