对420例血痕性别测定的研究

<正> 本文收集420例干血痕,男性364例,女性56例,经制片、国产盐酸阿的平染色,用奥林巴斯研究显微镜,对血痕Y荧光小体进行了观测,结果364例男性血痕的Y小体检出率平均为29.69％,其变动范围在9～63％;56例女性血痕的类Y小体平均检出率为0.75％,其变动范围0～4％;实验的同时,对150例男性血痕和25例女性血痕涂片,运用透     

荧光原位杂交技术在法庭科学DNA检验中的应用

目的运用荧光原位杂交技术结合激光显微切割技术,分离法医物证男女混合样本中的男性细胞和女性细胞,并进行DNA分型。方法通过双色荧光原位杂交,Y染色体标记上绿色信号,X染色体标记上红色信号,在荧光显微镜下识别男性细胞和女性细胞,并通过激光显微切割技术分别获得男性细胞和女性细胞进行DNA分型。结果运用荧光原位杂交技术,能够分别标记法医物证男女混合样本中的男性细胞和女性细胞,并通过激光显微切割技术获得各自的DNA分型。结论荧光原位杂交技术结合激光显微切割技术,可应用于法医物证男女混合样本的检验,提高个体识别能力。     

用荧光显微镜观察Y小体确定骨骼肌的性别

作者将人骨骼肌经冰冻切片,0.5％阿的平染色,用荧光显微镜观察,计数Y小体的出现率以确定性别。53例中34例男性Y小体的出现率在20～76％,平均为50.38％;19例女性的类Y小体的出现率在0～3％均值0.89％,将两者行t检验,t值等于13.93,P(0.01,差异极显著。通过对41例检材进行盲测,结果准确率达100％。     

一种用于降解DNA样本的性别鉴定方法

目的 建立一种采用PCR技术对降解DNA样本进行性别鉴定的新方法。方法 采用针对amelogenin基因X染色体外显子3bp缺失设计的引物AMELU1及AMELD1,对在室温环境下放置5－15年的男、女血痕标本各50例、毛发各20例、骨骼各20例以及现场提取5－－20天的男、女腐败肌肉各10例标本中提取的降解DNA样本进行扩增。用PGA（9％T,3％C）电泳、银染显带检测扩增产物。结果 所有样本均得到正确结果,男性检材表现为83bp的Y特异性及80bp的X特异性2条谱带,而女性检材仅有1条80bp的X特异性谱带。结论 用针对amelogenin基因X染色体外显子3bp缺失设计的引物AMELU1及AMELD1鉴定性别的方法灵敏、可靠、方便,是降解DNA检材性别鉴定十分理想的方法。     

疑似Amelogenin等位基因丢失的检测与分析12例

目的观察并分析亲权鉴定案件中Amelogenin等位基因丢失的案例,探讨Amelogenin等位基因丢失的类型、机制以及对性别鉴定的影响和应对方法。方法选择经Si Fa STRTM 23plex DNA身份鉴定系统检测,女性出现Amelogenin X的峰面积与相邻杂合子峰面积一致或低于相邻纯合子峰面积的1/2,男性出现Amelogenin X丢失的样本,进行X-STR分型及Amelogenin X测序,同时对出现Amelogenin Y丢失的男性样本,检测Y-STR分型及Y染色体性别决定区(sex-determining region of Y,SRY)进行验证。统计Amelogenin等位基因丢失的类型及丢失率,分析出现变异的机制及影响。结果 1例男性Amelogenin X等位基因丢失,经测序证实为引物结合区突变;4例女性疑似Amelogenin X等位基因丢失,经测序证实出现引物结合区突变的仅为1例。7例男性出现Amelogenin Y丢失,其中SRY阳性5例,SRY阴性2例。5例SRY阳性案件中4例可检出部分Y-STR分型,1例未检出Y-STR分型,2例SRY阴性案件均未检出Y-STR分型。Amelogenin等位基因丢失率约为0.029%。结论 Amelogenin X丢失不影响性别判定,Amelogenin Y丢失可能对性别造成误判,需要检测Y-STR或SRY来明确性别,对于未检出Y-STR分型且SRY检测为阴性的"男性",建议进行染色体核型分析及性别分化相关基因检测以进一步明确性别。     

用PCR扩增X-Y-特异片段性别鉴定的研究

采用5%Chelex-100处理方法提取 DNA,用 PCR 扩增 Amelogenin 基因片段检测血痕和毛根的性别。扩增一个样品只需1/10体积3mm~2血痕 Chelex-100处理液或1/10体积一根毛发 Chelex-100处理液(含模板 DNA)。100例血液样品结果显示,在男性可同时显现977bpX 特异片段和788bpY 特异片段,而在女性只观察到977bp X 特异片段,该方法用于性别鉴定可靠、灵敏、方便。     

用引物Y_3、Y_4和PCR方法鉴定性别的法医学应用

用Y3、Y4和Alu9．1、Alug．2两对引物和PCR方法检测陈旧血痕和毛根的性别获得成功。引物Y3、Y4扩增的靶序列位于Y染色体特异3．4Kb重复序列中，扩增产物为460bp；引物Alu9．1、Alu9.2用以扩增男女共有的Alu重复序列，扩增产物为130bP。室温保存13年之久的19例脐带血血痕（男性9冽，女性10例）和室温保存10～11个月的10例已知性别自然脱落毛根（男性6例，女性4例）的性别测定结果均正确；对一起凶杀案的血痕性别测定为定案提供了重要证据。本方法简化了样品的前处理过程。     

用引物Y_3,Y_4和DNA扩增技术作血液(痕)和毛根性别鉴定的研究

作者用引物Y_3、Y_4和DNA聚合酶链式反应(PCR)作微量人类血液(痕)和毛根的性别鉴定。扩增的靶序列位于Y染色体DNA特异3.4kb重复序列中,扩增产物为460bp。检材用量为:新鲜血液0.5μl、血痕纱纤维1mm、毛根单个。20例保存4个月的血痕与2例保存6年半的血痕性别判定结果均正确,无性别记载的保存9～11年的3例血痕显现了清晰的460bpY特异DNA扩增带。15例保存20天的自然脱落毛根性别判定结果均正确。本法省略了检材处理中的酚-氯仿抽提DNA等纯化步骤,既简化了实验操作,又减少了检验过程中外源DNA的污染机会和样品DNA的损耗,使这一性别鉴定方法更符合法医学实践的需要。     

根据Y小体的出现率确定脏器性别

作者用人的心、肝、脾、肺、肾、大脑、小脑制成涂片,用0.5％盐酸阿的平染色,pH5.5磷酸—枸橼酸缓冲液分化,在荧光显微镜下观察细胞核内的Y小体,计数其百分率。共观察了33具尸体的脏器,其中男性22人,女性11人。在男性脏器的细胞核中,Y小体的出现率为24％—80％,均值为48％;女性为0—8％,均值为0.76％;由此可见在两性间Y小体的分布不仅不相重迭,而且男性的下限与女性的上限相距甚远,故用本法进行脏器的性别鉴定是可行的。     

PCR扩增ZFY/ZFX基因鉴定人类干血痕性别

应用 PCR 技术同时扩增人 ZFY 和 ZFX 基因特异的 DNA 序列,在男性血痕中可检测到两种扩增产物,即340bp 长的 ZFY 基因及488bp 长的 ZFX 基因特异 DNA 片段;在女性血痕中仅可检测到488bp 长的 ZFX 基因特异 DNA 片段,据此判定干血痕性别。干血痕的最小检出需要量为0.125μl 血液量的血痕。室温保存10年的血痕可以准确判定性别。ZFY 基因位于 Y 染色体短臂。本方法同时检测两条性染色体,可以避免由于扩增失败或 Y 染色体长臂变异出现的假阴性或假阳性。扩增产物经琼脂糖凝胶电泳即可区分。     

The detection of Y chromosomes in bloodstains--a reevaluation

A method has been described for detecting Y chromosomes in the leukocytes of human bloodstains prepared on a variety of substrates. The factors that influence the proportion of chromosomes exhibiting a Y spot (the Y cell index) in a bloodstain are considered, including the subjective nature of assessment of the Y chromosome fluorescence, the substrate, and the age of bloodstain. In contrast to previous workers no decay in Y cell index with the age of the stain was observed. The results of a blind trial involving stains derived from case work, where from other evidence there was no doubt as to the sex of the donor, are presented. Sixty-five percent of the male bloodstains were correctly identified and no females were wrongly reported as male.     

单细胞分离荧光原位杂交法用于男女混合血DNA分型

目的采用单细胞分离荧光原位杂交法精确分离混合血样中男性和女性细胞并进行分型检验。方法收集男、女性血,按照男∶女为1∶5、1∶10、1∶20制备混合血样,加入0.075mol/L KCl 600μL,轻混、放置30min后加入150μL固定液离心留沉淀涂片,利用Vysis 30-161050试剂盒进行荧光原位杂交,并用PALM激光显微捕获系统分离出男、女性细胞,使用Identifiler试剂盒复合扩增并进行检测。结果捕获8个血细胞即可得到完整的DNA分型,且随着细胞数目的增多,检出率逐渐提高而等位基因丢失率逐渐降低。10个血细胞的检出率最高,为93.75%。5μL男性血液与本实验各比例女性血混合用本文方法检验均可获得男性分型。案例混合血斑经检验获得单一男性和女性分型。结论单细胞分离荧光原位杂交法可用于男女混合血样本中DNA分型检验。     

Quantitation of human genomic DNA through amplification of the amelogenin locus

An alternate method for quantitation of human genomic DNA is presented. Quantitative template amplification technology (abbreviated "Q-TAT") estimates the quantity of human DNA present in an extract by comparing fluorescence in X and Y amplicons produced from unknowns with fluorescence in a standard curve amplified from known quantities of reference DNA. Q-TAT utilizes PCR and electrophoresis with fluorescent detection/quantitation, precluding the need for new instrumentation, methodology, or quality assurance associated with slot-blot or real-time PCR. In a comparison study incorporating shared samples, Q-TAT was found to be more sensitive than widely used slot-blot methods but somewhat less sensitive than real-time PCR. Among samples containing DNA concentrations ranging from 100 pg/microL to 2-4 ng/microL, Q-TAT produced DNA concentration estimates that agreed reasonably well with either Quantiblot or real-time PCR. Q-TAT was reproducible with a typical coincidence of variation of about 35%. Quantitation of human DNA in this study involved summing fluorescence in X and Y amplicons in unknowns and quantitation standards. However, analyzing fluorescence in X and Y amplicons individually could allow estimates of male and female DNA present in mixtures to be made. Moreover, since X and Y amplicons exhibit sizes of 210 and 216 bp, respectively, the integrity as well as the concentration of the genomic DNA template can be assessed. Q-TAT represents an alternate method useful for the quantitation of human genomic DNA prior to amplification of STR loci used for identity testing purposes. The method uses existing equipment and procedures in conjunction with a well-characterized DNA standard to produce concentration estimates for unknowns that reliably produce STR profiles suitable for analysis.     

Sex determination of blood stains with a recombinant DNA probe: comparison with radioactive and non-radioactive labeling methods

A recombinant DNA probe hybridizing specifically to human repeat DNA sequence (pHY10) of which about 3000 copies are present on the Y chromosome was used for sex determination of degraded DNA samples of blood stains. Human blood stains of male and female origin were readily differentiated with the pHY10 DNA probe. This radioactive technique enabled reliable and sensitive sex determination from blood or dried blood stains greater than 20 years old. Less than 1 microliter of blood or 1 piece of 0.5 cm length thread of blood stain from cotton fabric was sufficient for the test using dot blot hybridization. Compared with the radioactive labeling method, the photobiotin labeling method showed one thirtieth to one fiftieth lower sensitivity and presented some problems which are expected to be resolvable.     

Remote spectroscopic identification of bloodstains

Blood detection and identification at crime scenes are crucial for harvesting forensic evidence. Unfortunately, most tests for the identification of blood are destructive and time consuming. We present a fast and nondestructive identification test for blood, using noncontact reflectance spectroscopy. We fitted reflectance spectra of 40 bloodstains and 35 nonbloodstains deposited on white cotton with spectroscopic features of the main compounds of blood. Each bloodstain was measured 30 times to account for aging effects. The outcome of the blood measurements was compared with the reflectance of blood-mimicking stains and various body fluids. We found that discrimination between blood and nonblood deposited on white cotton is possible with a specificity of 100% and a sensitivity of 98%. In conclusion, a goodness of fit between the sample's reflectance and the blood component fit may allow identification of blood at crime scenes by remote spectroscopy.     

Multiplex PCR and minisequencing of SNPs--a model with 35 Y chromosome SNPs

We have developed a robust single nucleotide polymorphism (SNPs) typing assay with co-amplification of 25 DNA-fragments and the detection of 35 human Y chromosome SNPs. The sizes of the PCR products ranged from 79 to 186 base pairs. PCR primers were designed to have a theoretical Tm of 60 +/- 5 degrees C at a salt concentration of 180 mM. The sizes of the primers ranged from 19 to 34 nucleotides. The concentration of amplification primers was adjusted to obtain balanced amounts of PCR products in 8mM MgCl2. For routine purposes, 1 ng of genomic DNA was amplified and the lower limit was approximately 100 pg DNA. The minisequencing reactions were performed simultaneously for all 35 SNPs with fluorescently labelled dideoxynucleotides. The size of the minisequencing primers ranged from 19 to 106 nucleotides. The minisequencing reactions were analysed by capillary electrophoresis and multicolour fluorescence detection. Female DNA did not influence the results of Y chromosome SNP typing when added in concentrations more than 300 times the concentrations of male DNA. The frequencies of the 35 SNPs were determined in 194 male Danes. The gene diversity of the SNPs ranged from 0.01 to 0.5.     

Use of a Y chromosome probe as an aid in the forensic proof of sexual assault

Currently, the most common procedures for the forensic identification of semen that may be present due to a sexual assault include the microscopic identification of spermatozoa, acid phosphatase activity, or the detection of PSA. However, not all cases of sexual assault result in the deposit of semen. Fluorescent In Situ Hybridization (FISH) has been found to be a very sensitive and specific method for detection of the Y chromosome from male cells. This study was undertaken to demonstrate the presence of epithelial cells of male origin in the postcoital vaginal tract using a commercially available probe. Results identified Y chromosome in intact epithelial cells on postcoital Days 1 through 4, and on Day 7. Additionally, Y chromosome positive epithelial cells were identified in vaginal swabs obtained following intercourse with no ejaculation. The method developed in this study demonstrates that FISH is a sensitive method for the identification of the presence of male epithelial cells in the postcoital vagina.     

Human identification and sex determination of dental pulp, bone marrow and blood stains with a recombinant DNA probe

Recombinant DNA hybridizing specifically to a 300 nucleotide repeat DNA sequence (BLUR8) of human specificity and to human repeat DNA sequence (pHY10) on the Y chromosome was used for human identification and sex determination of degraded DNA samples of blood stains, dental pulp, and bone marrow. This radioactive technique enabled reliable and sensitive human and sex determination from blood stains that were more than 80 years old. Less than 1 piece of 0.5 cm length thread of blood stain was enough for both tests. DNA from relatively fresh dental pulp and bone marrow was clearly identified. The human identification test, which could recognize up to 0.3 ng DNA correctly, was 3 to 5 times more sensitive than the sex determination test.     

An improved method for the determination of Y chromosomes in blood stains (author's transl)]

A new filter combination for fluorescence microscopy using SWP 440 interfernece filter for excitation and GG 455 as the barrier filter is described. In blind trials examining blood smears of 5 male persons and by examination of 3 weeks old blood stains a better Y chromosome demonstration has been obtained using this new technique in comparison with the "usual" filter combination: BG 12-530. In blind trials of up to 6 weeks old blood stains of one male and one female a reliable sex determination was made using the new technique.