性别特异性基因及其法医学应用

在人类,Ｙ染色体与性别有关。有Ｙ染色体者为男性。Ｙ染色体含有Ｙ染色体特异的高度重复的ＤＮＡ家族(ＤＹＺ1和ＤＹＺ2)、类ａｌｐｈａ(ａｌｐｈｏｉｄ)着丝粒重复家族ＤＮＡ(ＤＹＺ1)和Ｙ特异性的基因,包括ＳＲＹ、ＺＦＹ和Ａｍｅｌｏｇｅｎｉｎ等性别有关基因。它们在男性的减数分裂过程中,不与Ｘ染色体发生重组,按父系遗传[1]。因此,通过检测这些Ｙ染色体特异性的ＤＮＡ,就可以进行性别鉴定。性别判定是法医学中个人识别的内容之一。它可为刑事侦察提供线索。以往通过检测Ｙ染色质、性激素、男女之间差异的蛋白来判断性别,但由于对检材…     

新的人类遗传标记-脱氧核糖核酸酶Ⅰ

新的人类遗传标记－脱氧核糖核酸酶Ⅰ柳燕（司法部司法鉴定科学技术研究所；上海２０００６３）脱氧核糖核酸酶１（ＤＮａｓｅｌ）（ＥＣ．３，ｌ，４，５）是一种对ＤＮＡ具特异性的核酸内切酶，它能将单链或双链ＤＮＡ水解，生成３＇一端具游离羟基和在５＇一端具磷酸基...     

中国新疆维吾尔族群体DYS389Ⅰ/Ⅱ、DYS390 基因座及单倍型遗传多态性分析

在法医检验实践中 ,Ｙ染色体一直被用作性别鉴定。ＤＹＳ390、ＤＹＳ389Ⅰ /Ⅱ基因座是Ｙ染色体上分别以ＣＴＧＴ/ＣＴＡＴ为核心序列重复单位的微卫星。本文作者对中国新疆维吾尔族男性 3个Ｙ ＳＴＲ (Ｙｃｈｒｏｍｏｓｏｍｅｓｐｅｃｉｆｉｃｓｈｏｒｔｔａｎｄｅｍｒｅｐｅａｔ ,简称Ｙ ＳＴＲ)基因座基因型及单倍型构成进行了研究 ,并分析其遗传多态性。1　材料与方法1 1　样本ＤＮＡ56份静脉抗凝血随机采自中国新疆乌鲁木齐市无血缘关系健康维吾尔族男性个体。Ｃｈｅｌｅｘ法提取ＤＮＡ。1 2　引物序列[1] (Ｃｙｂｅｒｓｙｎ公司合成 )…     

广州地区汉族人群Y染色体多个STR位点的研究

为建立一套高度多态且实用性强的Ｙ－ＳＴＲｓ标记系统,本文用ＰＣＲ结合银染显色技术研究了１１１例广州汉族男性ＤＹＳ１９、ＤＹＳ３８９Ⅰ／Ⅱ、ＤＹＳ３９０等位基因及单倍型分布状况。结果显示：广州地区汉族男性ＤＹＳ１９位点有Ａ１、Ａ２、Ａ３、Ａ４、Ａ５五种等位基因,出现频率分别为１８．９％、３６．０％、３６．０％、７．２％、１．８％;ＤＹＳ３８９Ⅰ位点有Ｂ１、Ｂ２、Ｂ３、Ｂ４四种等位基因,出现频率分别为６．３％、５２．２％、１７．１％、２４．３％;ＤＹＳ３８９Ⅱ位点有Ｃ１、Ｃ２、Ｃ３、Ｃ４、Ｃ５五种等位基因,出现频率分别为１１．７％、３８．７％、２２．５％、１７．１％、９．９％,ＤＹＳ３９０位点有Ｄ１、Ｄ２、Ｄ３、Ｄ４、Ｄ５五种等位基因,出现频率分别为２．７％、９．９％、４６．８％、２７．９％、１２．６％;χ２检验表明上述各等位基因分布存在明显的地域差异。此外,还观察到７２种由上述座位共同构成的单倍型,单倍型多样性达０．９８０,表明该系统具有较强的个体识别能力     

一种改良的骨组织DNA提取方法

骨组织耐腐败 ,当其他软组织已完全腐败后 ,只能用骨组织进行种属鉴定 ,性别鉴定和个人识别。骨组织ＤＮＡ提取是骨组织ＤＮＡ分析的关键。作者曾用多种方法提取过骨组织ＤＮＡ ,本文报道一种改良的骨组织ＤＮＡ提取方法。方法1 去除骨骼表面的异物及残留的腐败软组织 ,用钢锯锯开骨组织 ,锯下骨松质骨片 2ｃｍ× 2ｃｍ× 0 5ｃｍ一块。2 ＥＤＴＡ脱钙 3天 ,每日更换一次脱钙液 ,(ＥＤＴＡ脱钙液 :0 2ＭＴｉｓ溶液 1 0 0ｍｌ +ＥＤＴＡ -2Ｎａ2 1 0 ｇ,用ＮａＯＨ缓慢调整ＰＨ7 0 )。3 剪碎已脱钙的海绵状骨松质于 2只 1 5ｍｌ消毒离心…     

中国汉族群体Y染色体DY390位点多态性分析

报告了对汉族Ｙ染色体ＤＹ３９０位点等位基因频率的调查结果。在９７名无关的汉族个体中发现有６个等位基因，等位基因的大小为２０３－２２３ｂｐ，最常见的等位基因大小是２１１ｂｐ和２１５ｂｐ。ＧＤ值０．６７７     

产气荚膜梭菌感染猝死并尸体迅速腐败1例

产气荚膜梭菌感染猝死并尸体迅速腐败１例顾晓生，薛义旗，王宝泉（１．南京医科大学法医学教研室；南京２１００２９２．南京市人民检察院技术处；南京２１０００２）ＳＰＥＥＤＹＣＡＤＡＶＩＣＰＵＴＲＥＦＡＣＴＩＯＮＩＮＡＤＥＡＴＨＯＦＡＣＵＴＥＨＥＭＯＲＲＨＡ...     

兔急性心肌缺血脱氢酶电镜—细胞化学变化的动态观察

为了研究急性心肌缺血脱氢酶变化的规律性，本文应用电镜酶细胞化学技术，通过结扎５０只家兔冠状动脉左前降支，观察心肌缺血后０．２５、０．５、１、１．５、２、４、６、１２、２４、３６、７２小时ＳＤＨ和ＬＤＨ的变化。结果显示：心肌缺血０．５小时后，ＳＤＨ和ＬＤＨ活性开始下降。同时伴有致密体的形成和超微结构的改变。随着缺血时间的延长，酶活性下降更加明显，最后消失。     

用非放射性标记MYO探针进行DNA指纹分析

用非放射性标记ＭＹＯ探针进行人的ＤＮＡ指纹分析，获得了清晰易读的ＤＮＡ指纹图，并用该方法调查了云南省的７８名无关个体，经统计学分析，计算出无关个体的相关几率是３．４×１０－１０，高于３２Ｐ标记的Ｍｙｏ探针。研究结果表明该方法是一种简便、快速、灵敏、可靠、经济的ＤＮＡ指纹图检测技术，可在法医鉴定及其它领域里得到更广泛的应用。     

硅珠法提取骨组织DNA

骨骼是硬组织 ,抗腐蚀性好 ,当其它软组织完全腐败后 ,骨组织在鉴定中可发挥重要作用。但由于骨组织中细胞含量少[1] ,加上环境因素的影响 ,使陈旧骨骼的ＤＮＡ提取成为鉴定工作的难点[2 ] 。本文研究了骨组织ＤＮＡ的硅珠提取法 ,并将其运用于法医物证检验。1　材料与方法1 1　样本收集75例骨骼样本来自本实验室受理的刑事案件检材 (检材保存时间最久为 14年 )。1 2　试剂脱钙液 :0 2ｍｏｌ/ＬＴｒｉｓ溶液 10 0ｍｌＥＤＴＡ Ｎａ2 10 ｇ ,ｐＨ 7 0 [3] 。裂解液 :12 ｇ ＧｕＳＣＮ + 10ｍｌ0 1ｍｏｌ/ＬＴｒｉｓ ＨＣｌｐＨ 6 4 + 2 2…     

Extraction of high quality DNA from biological materials and calcified tissues

Calcified tissues, such as bone and tooth, and some other sample types, such as those containing adhesive, present a challenge to standard extraction protocols. We have developed a lysis reagent, BTA™ lysis buffer, which is designed for use with PrepFiler™ Kit reagents. The BTA™ lysis buffer disrupts calcified tissue matrices and achieves effective extraction of DNA from pulverized bone and tooth samples. In addition, the BTA™ lysis buffer mildly but efficiently extracts DNA from challenging substrates like tape, chewing gum, and cigarette butts and, as with bone and tooth, DNA from these lysates is purified using established PrepFiler™ reagent extraction protocols.We successfully extracted DNA from powdered human bone samples, chewed gum and smoked cigarettes using BTA™ lysis buffer. Extraction yields for bone, gum and cigarette samples tested were consistent and reproducible. This extraction method efficiently removed potential PCR inhibitors from all samples tested, and C_T values for the internal PCR control of Quantifiler^® Human DNA Quantification Kit were consistent and within the normal range. The DNA extracted from these samples also provided conclusive profiles that were free of PCR artifacts when amplified using the AmpF?STR^® Identifiler^® PCR Amplification Kit. The protocol is easily adapted for automation.     

陈旧骨骼及牙齿的性别检验

为分析陈旧骨骼及牙齿的性别，建立了从陈旧人骨骼和牙齿中提出DNA的方法。通过PCR技术扩增，得到X－Y染色体上的单拷贝同源基因片断（AmelogeninGene）。结果显示，从死亡后2年、4年、7年和10年的4个骨骼和牙齿样品中，均成功地获得了特异的PCR扩增片段。女性为单一的106bp条带，男性为106bp和112bp两条谱带。其快速、简单、可靠，为陈旧骨骼和牙齿的性别鉴定提供了方法。     

A simple and cost-effective method for preparing DNA from the hard tooth tissue, and its use in polymerase chain reaction amplification of amelogenin gene segment for sex determination in an Indian population

The use of teeth as an important resource in the analysis of forensic case history by polymerase chain reaction (PCR) or other related methods has been reported. However, a major drawback in using teeth has been that the DNA is present only in trace amounts, and the methods to recover DNA from the flinty material have not been efficient or cost effective. In this report, we describe a method to prepare DNA from the hard tooth tissues. Our studies show that ultrasonication of teeth samples yields sufficient amounts of good quality DNA useful for PCR-based diagnostic methods. The teeth could serve as a reliable source of DNA for amplification-based forensic methods in sex determination. DNA could be obtained from any tooth, regardless of the age of subject. Furthermore, by using the AMEL gene-based primers in PCR, we have shown that the AMEL gene serves as a good marker for sex determination in the Indian population. In our study, the PCR-based method was sensitive and proved to be successful for sex determination with a complete specificity.     

A polymerase chain reaction (PCR) method for sex and species determination with novel controls for deoxyribonucleic acid (DNA) template length.

Human X and Y chromosome alpha-satellite sequences lying within higher order repeats were amplified by the polymerase chain reaction (PCR) in genomic deoxyribonucleic acid (DNA) isolated from blood, bone, and several other tissues and specimens of potential forensic science interest. X and Y sequences could be coamplified under some of the PCR conditions employed. Monomorphic sequences in the 3'-apolipoprotein B gene (designated "H") and in an alpha-satellite higher order repeat on Chromosome 17 (p17H8, D17Z1) were likewise amplified in the specimens. X and Y sequence amplification can provide information about the sex of origin. Amplification of the X, H, and D17Z1 sequences was found to be primate-specific among the common animals tested and can thus provide species of origin information about a specimen. The authors suggest that amplification of X and D17Z1 or H sequences might provide "relaxed" and "stringent" controls for appropriate PCR amplification tests on forensic science specimens. Testing was carried out using PCR protocols that employed Thermophilus aquaticus (Taq) and Thermus flavis (Replinase) thermostable DNA polymerases.     

Extraction and amplification of authentic DNA from ancient human remains

A total of 36 ancient human remains from 12 individuals (three tooth/bone samples each) and one sample each of three individuals from the newest time was typed in a blind study using the amelogenin sex test. Prior to this molecular sex determination the sex of the individual was determined morphologically. The success rate of the amelogenin amplifications was >90%. For every individual an unambiguous molecular sex typing result was obtained. Furthermore, the morphological and molecular sex determinations were in accordance with each other, giving evidence for the authenticity and ancient origin of the polymerase chain reaction (PCR) amplifications.     

Difficulties of sex determination from forensic bone degraded DNA: A comparison of three methods

Sex determination is of paramount importance in forensic anthropology. Numerous anthropological methods have been described, including visual assessments and various measurements of bones. Nevertheless, whatever the method used, the percentage of correct classification of a single bone usually varies between 80% and 95%, due to significant intra- and inter-population variations, and sometimes variations coming from secular trends. DNA is increasingly used in a forensic context. But forensic DNA extraction from bone raises several issues, because the samples are very often badly altered and/or in very small quantity. Nuclear DNA is difficult to get from degraded samples, according to low copy number, at least in comparison with mitochondrial DNA. In a forensic context (as in a paeleoanthropological context) DNA sex determination is usually complicated by the weak amount of DNA, the degraded nature of nucleic acids, the presence of enzymatic inhibitors in DNA extracts, the possible faint amplification of Y band and the risk of contamination during either excavation or manipulation of samples.The aim of this work was to compare three methods of DNA sex determination from bones: procedure #1 using a single PCR amplification, procedure #2 using a double PCR amplification, and procedure #3 adding bleaching for decontamination of the bone, instead of simply rubbing the bone. These processes were applied to samples of bones (49 samples coming from 39 individuals) that were in various states of post mortem alteration.The main results are the following. (i) No DNA could be extracted from three skulls (parietal bones, mastoid process), the compact bone of one rib, and the diaphysis of one femur; (ii) there was a contamination in three skulls; and (iii) the Y band did not appear in two male cases, with one of the three procedures (male tibia, procedure #2) and with procedures #2 and #3 (male femur).This study emphasises the main issue while working with altered bones: the impossibility to extract DNA in some cases, and, worth of all, the contamination of the sample or the faint amplification of Y band which leads to a wrong sex answer. Multiple and significant precautions have to be taken to avoid such difficulties.     

Fragment analysis in forensic anthropology

Anthropological analysis of fragmentary evidence can be challenging but diverse methods allow substantial information to be gleaned. Scanning electron microscopy/energy dispersive X-ray spectroscopy enables determination if bone and/or tooth tissue is present. Protein radioimmunoassay or DNA analysis can establish the species present. Histological analysis can assist in species determination and reveal information about thermal changes. Radiocarbon analysis with special reference to the modern bomb-curve can clarify the postmortem interval. Anthropologists should also be aware that DNA analysis not only can enable positive identification but assist in the evaluation of sex and age at death.     

Real-time PCR designs to estimate nuclear and mitochondrial DNA copy number in forensic and ancient DNA studies

We explore different designs to estimate both nuclear and mitochondrial human DNA (mtDNA) content based on the detection of the 5' nuclease activity of the Taq DNA polymerase using fluorogenic probes and a real-time quantitative PCR detection system. Human mtDNA quantification was accomplished by monitoring the real-time progress of the PCR-amplification of two different fragment sizes (113 and 287 bp) within the hypervariable region I (HV1) of the mtDNA control region, using two fluorogenic probes to specifically determine the mtDNA copy of each fragment size category. This mtDNA real-time PCR design has been used to assess the mtDNA preservation (copy number and degradation state) of DNA samples retrieved from 500 to 1500 years old human remains that showed low copy number and highly degraded mtDNA. The quantification of nuclear DNA was achieved by real-time PCR of a segment of the X-Y homologous amelogenin (AMG) gene that allowed the simultaneous estimation of a Y-specific fragment (AMGY: 112 bp) and a X-specific fragment (AMGX: 106 bp) making possible not only haploid or diploid DNA quantitation but also sex determination. The AMG real-time PCR design has been used to quantify a set of 57 DNA samples from 4-5 years old forensic bone remains with improved sensitivity compared with the slot-blot hybridization method. The potential utility of this technology to improve the quality of some PCR-based forensic and ancient DNA studies (microsatellite typing and mtDNA sequencing) is discussed.     

A Powder-free DNA Extraction Workflow for Skeletal Samples

The processing of skeletal material poses several challenges for forensic laboratories. Current methods can be laborious, time-consuming, require dedicated equipment, and are vulnerable to contamination. In this study, various sample mass (1 × 50 mg, 3 × 50 mg, and 1 × 150 mg chip(s)) and incubation times (2, 4, and 16 h) were tested using the PrepFiler^® BTA™ Forensic DNA Extraction Kit to digest whole bone chips in lieu of powdering. The most effective method was then applied to bones and tooth fragments collected from contemporary human cadavers exposed to various environmental conditions using an automated platform. Over a third of the samples tested generated full DNA profiles without having to powder the bone/tooth fragment or further alter the manufacturer's protocol. However, for most samples resulting in incomplete STR profiles due to low amounts of DNA, slightly better results were achieved with powdered tissue. Overall, this work demonstrates the potential use of a faster, nonpowdering DNA extraction method for processing skeletal samples as an effective first-pass screening tool.     

The use of SEM/EDS analysis to distinguish dental and osseus tissue from other materials

With increasing frequency, relatively small, fragmentary evidence thought to be osseous or dental tissue of human origin is submitted to the forensic laboratory for DNA analysis with the request for positive identification. Prior to performing DNA analysis, however, it is prudent to first perform a presumptive test or "screen" to determine whether the questioned material may be eliminated from further consideration. When material is shown not to be consistent with bone/teeth, DNA testing is not performed. When such determinations cannot be made from gross morphological features, elemental analysis can be indicative. This presumptive test is made possible by applying scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) in conjunction with an X-ray spectral database recently developed by the FBI laboratory. This database includes spectra for many different materials including known examples of bone and tooth from many different contexts and representing the full range of taphonomic conditions. Results of SEM/EDS analysis of evidence can be compared to these standards to determine if they are consistent with bone and/or tooth and, if not, then what the material might represent. Analysis suggests that although the proportions and amounts of calcium and phosphorus are particularly important in differentiating bone and tooth from other materials, other minor differences in spectral profile can also provide significant discrimination. Analysis enables bone and tooth to be successfully distinguished from other materials in most cases. Exceptions appear to be ivory, mineral apatite, and perhaps some types of corals.