基于二代测序平台的微单倍型位点的分型研究

目的建立基于二代测序平台的微单倍型分型方案,调查其在中国南方汉族人群中的多态性,探讨其法医学应用价值。方法以20个微单倍型位点为研究对象,利用多重PCR构建靶向扩增子文库,以二代测序为检测手段,采用生物信息学方法构建个体微单倍型,最后进行多态性分析。结果总体测序量为2.12G,覆盖所有片段,平均覆盖深度为3353×。微单倍型内含72个SNP位点的观测杂合度范围为0.109~0.587,平均值为0.364;而20个微单倍型位点本身的观测杂合度范围为0.198~0.837,平均值为0.726,均高于SNP位点。20个微单倍型位点中仅一个位点未通过Hardy-Weinberg平衡检验,剩余19个位点的有效等位基因数值为3.119~7.170,多态信息含量为0.620~0.845,平均多态信息含量为0.711。19个有效微单倍型位点的匹配概率为0.044~0.181,累积匹配概率为3.132×10^-19。结论本次研究证实了19个微单倍型的参数效能与常用15个STR基因座相当,可独立应用于法医个体识别并具潜在混合物分析价值,该结果为法医遗传学实践提供更多选择。     

D18S51及其侧翼区3个SNP组成的SNP-STR在亲子鉴定中的应用

目的将一个单倍型区块内的遗传标记单核苷酸多态性(SNP)和短串联重复序列(STR)组成SNPSTR单倍型,调查其在成都汉族人群中的分布,并探讨其在特殊亲子鉴定案例中的应用价值。方法选取DNA联合索引系统(combined DNA index system,CODIS)中突变率较高的基因座D18S51,与其侧翼区的3个SNP位点(rs8089331、rs8094489、rs7236090)组成SNP-STR,通过巢式等位基因特异性PCR的方法获得SNP-STR单倍型,调查该单倍型在75名成都汉族人群中的分布,并应用于两例D18S51基因座不符合遗传规律的二联体亲子鉴定案件。结果成功建立SNP-STR分型方法,在成都汉族人群中共发现43种单倍型,多态性为0.948 6,并成功解决了两例二联体亲子鉴定案件。结论 SNP-STR具有良好的多态性,有望应用于特殊的亲缘关系鉴定。     

广东地区汉族人群VEGF基因5′端SNP位点遗传多态性

目的调查广东地区汉族人群VEGF基因5′端SNP位点的遗传多态性,为法医学应用及群体遗传学研究提供基础数据。方法 DNA微测序技术SNaPshot分析184例广东地区无关个体VEGF基因5′端4个SNP位点(rs699947、rs1570360、rs833061、rs2010963)的遗传多态性。应用PowerMarker v3.25软件进行统计分析。结果 184例广东地区汉族无关个体VEGF基因5′端4个SNP位点基因分布均符合Hardy-Weinberg平衡(P0.05),每个位点均检出3种基因型。rs833061和rs699947位点紧密连锁。共检出6种单倍型,其中C-G-T-C、C-G-T-G、A-A-C-G、A-G-C-G频率均10%,为主要单倍型。rs699947、rs833061、rs2010963位点的个人识别率为0.583~0.634,非父排除率为0.133~0.144;4个SNP构成单倍型的个人识别率为0.868,非父排除率为0.438。结论广东地区汉族人群VEGF基因5′端序列呈现出高度遗传多态性,可作为个人识别和亲权鉴定的遗传学指标,同时可用于相关疾病关联分析。     

中国朝鲜族H19基因上游差异甲基化区SNP分布

目的调查中国朝鲜族群体中H19基因上游差异甲基化区(differentially methylated region,DMR)SNP及单倍型分布,为法医学应用及群体遗传学研究提供基础数据。方法收集中国朝鲜族101份无关个体血样和14份来自5个亲缘关系已知的两代家系血样,用PCR-循环测序、McrBC消化DNA后PCR方法检测H19基因上游DMR的SNP,并用亲源印记等位基因(parentally imprinted allele,PIA)分型法进行单倍型检测,再计算相关遗传学参数。结果在H19基因上游DMR 1174bp的目的基因扩增产物中,共检出13个SNP(rs10840167、rs2525883、rs12417375、rs4930101、rs2525882、rs2735970、rs2735971、rs11042170、rs2735972、rs10732516、rs2071094、rs2107425、rs4930098)和5种单倍型,有9个SNP属于高鉴别能力的遗传标记,其单倍型具有较高的个人识别率,单倍型平均基因多样性(GD)为0.714。应用McrBC酶消化基因组DNA的PIA分型法确定了家系子代样本的母源单倍型。结论 H19基因上游DMR在中国朝鲜族群体中具有很高的遗传多态性,母源单倍型的确定进一步提高了印记基因的法医学鉴定效能。     

广东汉族人群H19基因上游差异甲基化区SNP

目的调查广东汉族人群中H19基因上游差异甲基化区(differentially methylated region,DMR)的单核苷酸多态性(SNP)及单倍型。方法应用PIA分型法,以限制性内切酶Mcr BC、HpaⅡ消化基因组DNA分别获得个体单亲源DNA模板链,经测序,分别获得个体H19基因上游DMR单亲源SNP等位基因、基因型及单倍型数据。结果共检出13个SNP(rs10840167、rs2525883、rs12417375、rs4930101、rs2525882、rs2735970、rs2735971、rs11042170、rs2735972、rs10732516、rs2071094、rs2107425、rs4930098)及1个突变点(g7351c)。所有位点经统计学分析均符合Hardy-Weinberg平衡定律(P0.05)。除rs12417375位点DP值为0.279,其余12个SNP DP值在0.446~0.614;g7351c突变点DP值为0.013,提示为南方汉族民族特异性位点。共检出8种单倍型(命名为单倍型1~8),其中有3种为新发现的单倍型,其DP、PIC、PE及H分别为0.891、0.714、0.524和0.758。结论 PIA分型法获得的H19基因上游DMR SNP位点及其单倍型遗传标记系统具有较高的鉴别能力,在法医学鉴定中具有较好的实用价值。     

用dHPLC技术检测线粒体DNA编码区单核苷酸多态性

目的研究线粒体DNA(m tDNA)编码区单核苷酸多态性,建立检测m tDNA编码区单核苷酸多态性(SNP)的变性高效液相色谱(dHPLC)方法。方法设计针对线粒体DNA编码区nt10287-10679及nt8507-8805引物,应用dHPLC技术检测其序列多态性。结果100例中国汉族无关个体中,m tDNA nt10287-10679检出13个SNP位点,13种单倍型,基因多样性(H)为70.79%,偶合概率(P)为29.92%;m tDNA nt8507-8805检出10个SNP位点,12种单倍型,H为70.42%,P为30.28%;两段序列联合起来共检出23个SNP位点,23种单倍型,H为84.14%,P为16.70%。结论所建立的dHPLC方法可用于快速、准确地检测m tDNA编码区序列多态性;m tDNA编码区多态性位点作为m tDNA控制区多态性位点的补充,联合应用可以提高m tDNA的个体识别能力。     

单核苷酸多态性与法医学DNA分型技术

单核苷酸多态性(single nucleotide polymorphism,SNP)分型技术越来越成为法医学领域关注的热点,它在研究Y染色体或线粒体单倍型以及DNA表型的分析中具有重要应用价值。本文着重比较分析了SNP技术与片段长度多态性技术之间的优劣,同时就当前STR位点识别概率与所需选择的SNP位点数进行探讨。此外,本文还就各类SNP分型方法的优缺点及其法医学应用进行了论述。     

STR基因座单倍型的推断方法初探

本文参考Browning SR等提出的以SNP等位基因频率为基础,通过统计学模型推断SNP单倍型的方法,初步探讨亲权鉴定中STR基因座单倍型的推断方法。以两个处于连锁不平衡状态的X-STR基因座的女性分型结果为例进行说明。本方法为STR单倍型的推断提供了一个思路,有助于更科学准确地进行STR分型结果的解释。     

MALDI-TOF-MS对Y染色体上66个二等位基因的检测

目的分析华东地区汉族人群Y染色体上66个二等位基因遗传标记的多态性,并评价其法医学应用价值。方法采用多重PCR联合基质辅助激光解吸/电离-飞行时间质谱(matrix-assisted laser desorption/ionization time-of-flight mass spectrometry,MALDI-TOF-MS)技术对华东地区205名汉族男性无关个体Y染色体上66个二等位基因遗传标记进行分型研究,使用直接计数法统计待测位点的等位基因频率,用公式计算基因多样性和单倍型多样性,用Arlequin v3.5.2.2软件检测该体系的单倍型并且进行群体遗传学比较。结果其中60个二等位基因遗传标记在华东地区汉族男性人群中呈多态性分布,基因多样性为0.0385~0.501 9,共检测到85种单倍型,单倍型多样性为0.970 3。部分SNP位点的等位基因分布在华东地区汉族人群和新疆汉族人群、广东汉族人群差异具有统计学意义。结论 60个二等位基因遗传标记及其检测体系在亲权鉴定和个体识别中可补充提供遗传信息,MALDI-TOF-MS技术可以进行二等位基因遗传标记的分型检测。     

Y染色体3个SNP基因座及其单倍型的遗传多态性和群体差异

目的 探讨人类Y染色体3个SNP基因座及其单倍型的遗传多态性和群体差异。方法 应用PCR-RFLPs结合DNA序列分析技术,对140例来自中国藏族、日本、南非黑人及南非白人男性的Y染色体M4、M9和M122基因座的等位基因进行分析。结果 全部样品M4基因座的等位基因均为野生型M4A,未发现多态性。共检出3种单倍型,黑人个体均为野生型单倍型M4A/M9C/M122T。白人个体有8例单倍型为M4A/M9G/M122T,未检出等位基因M122C。日本及中国藏族群体以单倍型M4A/M9C/M122T为主,频率分别为0.50和0.65,未检出单倍型M4A/M9C/M122C,个人识别机率与父权排除率分别为0.6191和0.4994。单倍型频率分布在中国藏族和日本群体之间存在显著性差异(P<0.01)。结论 单倍型M4A/M9G/M122C为亚洲人特征,M9和M122基因座在中国藏族和日本群体中具有较高的遗传多态性,并显示出明显的人种和群体差异。     

Empirical haplotype calling and probabilistic interpretation of microhaplotype profiles

MicroHapulator’s empirical microhaplotype calling algorithm produces profiles well-suited for forensic analyst interpretation and probabilistic interpretation.     

A new approach to detect a set of SNP-SNP markers: Combining ARMS-PCR with SNaPshot technology

Microhaplotypes have become a new promising forensic genetic marker in recent years. The microhaplotype composed of two SNPs, SNP-SNP, indicates strong application potential because of the shortest fragment and good polymorphism and without the interference of stutter and high mutation rate as short tandem repeats (STR) and low polymorphism as a single SNP. Currently, the most common method to detect microhaplotypes is massively parallel sequencing (MPS), however its high cost and the need for special instruments limit its use in general forensic laboratories. In this study, we screened out 8 new SNP-SNP loci and established a new detection method by associating multiplex ARMS-PCR and SNaPshot technology. Firstly, we introduced ARMS-based PCR for SNP1. Then, SBE primers for SNaPshot assay were designed as 20–25 bp upstream complementary sequence next to the position of SNP2. Finally, 8 loci were built into one panel based on different SBE primer lengths and fluorescence colors. In brief, by combing ARMS-PCR and SNaPshot technology, it is easy and fast to profile the SNP1 and SNP2 orderly of the SNP-SNP microhaplotype based on CE platform. Our results suggested that the 8 loci have relatively high polymorphism as well as robust performance.     

Microhaplotype loci are a powerful new type of forensic marker

Modern sequencing technology makes it possible to genotype polymorphisms with high throughput and high multiplexing. We have searched for and identified many loci with 2 or more SNPs within the expanse of a 200 bp single sequence run and show that when linkage disequilibrium is not complete these loci have multiple alleles detected as phase-known haplotypes. These microhaplotype loci (microhaps) are a powerful tool for individual identification, ancestry inference, and determining family/clan relationships.     

Identifying the scene of a crime through pollen analysis

The forensic analysis of pollen involves the comparison of crime scene and reference pollen samples. Successful matches are frequently used to solve time- or location-related crimes. Despite its prospects in criminal investigation, forensic palynology is still underused in casework due to inherent shortcomings such as its limited evidential weighting, scarcity of skilled palynologists dedicated to forensic casework and the laborious nature of analytical procedures. To address these challenges, the current state-of-the-art in forensic palynology is transiting from the traditional light microscopic methods that dominated the early days of palynology to more contemporary approaches like Raman spectroscopy, stable isotope analysis and DNA metabarcoding. The major challenges of these methods, however, include a lack of optimisation to forensic expectations and the unavailability of robust databases to permit accurate data interpretation, and quests to resolve these problems constitute the theme of current research. While reiterating the usefulness of pollen analysis in criminal investigation, this report recommends orthogonal testing as a way of improving the evidential weighting of forensic palynology.     

Not just welfare over justice: Ethics in forensic consultation

The ethics of forensic professionalism is often couched in terms of competing individual and societal values. Indeed, the welfare of individuals is often secondary to the requirements of society, especially given the public nature of courts of law, forensic hospitals, jails, and prisons. We explore the weaknesses of this dichotomous approach to forensic ethics, offering an analysis of Psychology's historical narrative especially relevant to the national security and correctional settings. We contend that a richer, more robust ethical analysis is available if practitioners consider the multiple perspectives in the forensic encounter, and acknowledge the multiple influences of personal, professional, and social values. The setting, context, or role is not sufficient to determine the ethics of forensic practice.     

SNPs在个体识别与表型预测中的研究进展

单核苷酸多态性（single nucleotide polymorphism,SNP）作为第三代遗传标记,具有分布广泛、突变率低、遗传稳定及易于自动化高通量快速检测分析的特点。同时,因其扩增片段长度短、不存在复制滑动,所以利于腐败降解、痕量检材的检测。随着研究的深入,SNPs在法医学领域受到了广泛重视,与表型（ABO血型、色素沉积及颅面形态）相关的SNPs有望用于预测嫌疑人的基本特征,为案件侦破提供新的思路。本文对近年来SNPs在个体识别和表型预测的研究进行总结,介绍该领域的研究进展,为法医学工作者提供参考。     

Massively parallel sequencing and the emergence of forensic genomics: Defining the policy and legal issues for law enforcement

Use of DNA in forensic science will be significantly influenced by new technology in coming years. Massively parallel sequencing and forensic genomics will hasten the broadening of forensic DNA analysis beyond short tandem repeats for identity towards a wider array of genetic markers, in applications as diverse as predictive phenotyping, ancestry assignment, and full mitochondrial genome analysis. With these new applications come a range of legal and policy implications, as forensic science touches on areas as diverse as ‘big data’, privacy and protected health information. Although these applications have the potential to make a more immediate and decisive forensic intelligence contribution to criminal investigations, they raise policy issues that will require detailed consideration if this potential is to be realised. The purpose of this paper is to identify the scope of the issues that will confront forensic and user communities.     

Accuracy Rates of Sex Estimation by Forensic Anthropologists through Comparison with DNA Typing Results in Forensic Casework

A common task in forensic anthropology involves the estimation of the biological sex of a decedent by exploiting the sexual dimorphism between males and females. Estimation methods are often based on analysis of skeletal collections of known sex and most include a research‐based accuracy rate. However, the accuracy rates of sex estimation methods in actual forensic casework have rarely been studied. This article uses sex determinations based on DNA results from 360 forensic cases to develop accuracy rates for sex estimations conducted by forensic anthropologists. The overall rate of correct sex estimation from these cases is 94.7% with increasing accuracy rates as more skeletal material is available for analysis and as the education level and certification of the examiner increases. Nine of 19 incorrect assessments resulted from cases in which one skeletal element was available, suggesting that the use of an “undetermined” result may be more appropriate for these cases.     

法医物证学miRNA分析的研究进展

在种属和体液鉴定及降解检材等特殊案件的分析时,转录水平的miRNA所具有的生物属性及表达特点,使其能够发挥基因组DNA所不具备的价值。本文通过概述法医物证学miRNA研究的现状,对法医miRNA分析的研究策略和法医物证学应用前景进行了综述,以期为法医miRNA分析的应用研究提供借鉴。