Forensic Imaging‐Guided Recovery of Nuclear DNA from the Spinal Cord*,†

Abstract: Our objective is to document the recovery of DNA from the spinal cord or surrounding dura mater in 11 cases of severely burned human remains. Radiographs established that portions of charred tissue contained spine segments. Multidetector computed tomography (MDCT) revealed that each spine specimen contained an intact spinal cord remnant. A full DNA profile was obtained from seven specimens using spinal cord dura mater in six specimens and spinal cord medulla in one specimen. A partial profile was obtained from four specimens (spinal cord dura mater, 2; spinal cord medulla, 2). Bone and muscle surrounding the spinal cord appear to insulate nucleic acid containing tissue from critical thermal degradation. The spinal cord, which is easily identified by MDCT examination of remains and easily recovered at the postmortem examination, can be a source of DNA with extraction yields comparable with other tissue sources. Specimens of dura mater are preferable as processing time is faster than bone.     

循环次数与体系对DNA检测灵敏度的影响

目的探讨通过增加PCR循环次数和缩小扩增体系改善DNA检测灵敏度的可行性。方法将10例无血缘关系健康志愿者精液DNA样本分别定量为50、40、30、25、20、15、10 pg/μL,分别用10、5、3μL的体系和28、30、32、34、36次循环进行扩增,用3130遗传分析仪检测15个常染色体STR基因座。结果 28次循环下,3μL体系可对40pg/μL及以上样本正确分型。20pg/μL及以上样本在10、5、3μL体系中,34次循环均可正确分型,增加到36次循环,出现非特异性谱带,无法正确分型。结论增加循环次数和缩小扩增体系在一定程度上可以提高DNA检测的灵敏度。     

19个常染色体与4个Y染色体STR复合扩增体系的建立

目的建立19个常染色体STR及Amelogenin和4个Y染色体STR基因座复合扩增体系,并对其效能进行评估。方法用五色荧光标记20＋4Y—STR基因座,建立同步扩增检测体系,用ABI3130XL遗传分析仪对扩增产物进行电泳,GeneMapperID3．2软件进行基因分型;检测体系的灵敏度、均衡性、稳定性、特异性、同一性和稳定性,并观察混合、降解及微量检材的分型情况。结果采用本文体系,DNA模板量在0．05～1．00ng时,分型准确,均衡性、特异性好;混合、降解及微量检材分型正确。该19个常染色体STR基因座的累计个人识别率大于0．999999999,三联体累计非父排除率达0．999999985,Y—STR单倍型多态性为0．592。结论本文建立的复合扩增体系分型准确,稳定,在法医学案件检验及数据库建设等方面有良好的应用前景。     

12个mini-X-STR和Amel基因座荧光标记复合扩增体系的初步研究

目的研究建立12个mini-X-STR和Amel基因座复合扩增体系。方法选择DXS101、DXS10159、DXS10162、DXS10164、DXS6789、DXS7133、DXS7423、DXS7424、DXS8378、DXS981、GATA165B12和GA-TA31E08共12个X-STR与Amelogenin基因座,自行设计引物,分别采用FAM、HEX、Tamra、ROX四色荧光标记5′端,并进行必要的修饰,按照合适的引物浓度进行混合。对97个血痕样本进行复合扩增,并用ABI3130XL进行电泳和分型。结果所建立的荧光标记复合扩增体系能够得到清晰、明确的分型图谱,灵敏度达50pg,稳定性、重复性与平衡性较佳。结论本研究建立的12个mini-X-STR和Amel基因座荧光标记复合扩增体系统检验方法简单,灵敏度高,适合实际办案的需要。     

Mitochondrial DNA and STR typing of matter adhering to an earphone

STR typing and mitochondrial DNA (mtDNA) sequencing were performed on the matter adhering to an earphone found at a crime scene. Experimental studies were carried out using the earphones provided by volunteers. By means of immunohistochemistry, keratinocytes and a portion of nucleated epithelial cells were proven to exist in the contents from the earphones. DNA was extracted by means of the phenol/chloroform method, and the low quantity of extracted DNA was found to be highly degraded. Six STR loci, CSFIPO, TPOX, TH01, F13A01, FESFPS and vWA, were PCR amplified and typed by using two triplex systems (CTT and FFv Multiplexes, Promega, WI), and an amelogenin locus was determined as well. Although partial profiles were observed in some experimental samples, all STR loci could be typed when a considerable amount of high molecular weight DNA was obtained (>0.5 ng/microL). Amplification and sequencing of mtDNA hypervariable region I(15997-16401) and hypervariable region 11(29-408) were all successful. The mitochondrial DNA sequence of the actual case sample, comprising two hypervariable regions and a total of 785 base pairs, showed eight mutations and two insertions with respect to the standard published reference sequence. The genotype was unique in the three published Japanese databases. These results suggest that it is possible to analyze mtDNA from minute amounts of materials and from degraded materials more effectively and routinely in forensic practice.     

尿液及尿斑DNA分型的研究

目的研究尿液及尿斑的DNA提取及其检验。方法用Chelex100法及QIAampMiniKit提取尿液及尿斑样本中的DNA,进行PCR扩增及STR检验。结果新鲜的及存放时间在12h以内的尿液样本能得到较好的分型结果;存放2d左右的尿液样本有50%能检出基因型;存放7d及更长时间的尿液样本全部不能检出基因型;尿斑样本的分型成功率很低。结论较新鲜的尿液样本均能进行DNA分型,在法医检案中具有应用价值。     

激光显微捕获技术用于尿液脱落细胞DNA检测

目的采用激光显微捕获技术（LCM）捕获尿液脱落细胞,并进行STR分型。方法收集10份健康成人尿液样本,根据储存时间分组,其中新鲜尿液组（≤24h）分别采用Chelex-100及LCM联合DNA IQTM提取法提取DNA,储存尿液组（〉24h）再分为4℃组和室温组,分别在4～30d内不同时间点采用LCM联合DNA IQTM提取法提取DNA;各组提取的模板DNA进行扩增及SRT分型检验。结果新鲜尿液组采用LCM联合DNA IQTM提取法提取DNA,所有样本均可检出全部基因座（16个）,采用Chelex-100法则在部分基因座上出现等位基因丢失、非特异性扩增、峰值低等现象;4℃储存10d和室温储存4d以内的尿液经检验可明确判读12个以上基因座,4℃20～30d及室温7d,可检出7个以上基因座。结论 LCM技术可用于尿液检材的DNA分型检验,且检材应尽可能4℃保存并尽快检验。     

DNA typing of samples for polymarker, DQA1, and nine STR loci from a human body exhumed after 27 years

A body was exhumed from the ground after 27 years. Samples of femur bone, tooth, and a fingernail were collected and successfully subjected to DNA extraction, quantitation, amplification, and subsequently typed for DQA1, polymarker, and nine STR loci. All three types of samples were typed for D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S17, D7S820, and amelogenin using ABI Prism 377 DNA sequencer.     

23个STR基因座荧光复合扩增体系的法医学应用评估

目的评估新建立的23个STR复合扩增体系EX23的法医学应用价值。方法使用磁珠法提取样本DNA,应用23个STR复合扩增体系进行扩增,ABI3130XL遗传分析仪对扩增产物进行电泳,GeneMapperID 3.2软件进行基因分型,对法医学应用参数、灵敏度、种属、脱落细胞检材及降级检材分型效果进行观察,并与Sinofiler试剂盒比较。结果 DNA模板量在0.05~1.00ng时,各基因座分型结果清晰准确,均衡性好、特异性强。应用该复合扩增体系检验混合样本、降解检材及脱落细胞检材,均能获得正确的分型结果。统计结果显示该23个STR基因座累计个人识别（TDP）率达0.999999999,三联体累计非父排除率（CPE）达0.999999997。结论新建立的23个STR复合扩增体系分型效果良好,在广东地区汉族人群中具有高度多态性,可满足日常法医鉴定的需要。     

不同分型方法的STR分型差异

目的调查不同的STR分型系统之间分型的一致性。方法 10 0例不同个体的DNA样本分别用单位点聚丙烯酰胺凝胶银染法和PowerPlex16System试剂盒对 13个法医学常用STR位点进行基因分型 ,并比较两种不同分型系统间的分型结果。结果 1例样本在D8S1179位点出现了分型不一致的结果 :银染法的基因型为 12 / 14 ,而用PowerPlex16System试剂盒的分型则为 12 / 15。结论不同的STR分型系统可导致不同的基因分型     

Rapid and high-throughput forensic short tandem repeat typing using a 96-lane microfabricated capillary array electrophoresis microdevice

A 96-channel microfabricated capillary array electrophoresis (muCAE) device was evaluated for forensic short tandem repeat (STR) typing using PowerPlex 16 and AmpFlSTR Profiler Plus multiplex PCR systems. The high-throughput muCAE system produced high-speed <30-min parallel sample separations with single-base resolution. Forty-eight previously analyzed single-source samples were accurately typed, as confirmed on an ABI Prism 310 and/or the Hitachi FMBIO II. Minor alleles in 3:1 mixture samples containing female and male DNA were reliably typed as well. The instrument produced full profiles from sample DNA down to 0.17 ng, a threshold similar to that found for the ABI 310. Seventeen nonprobative samples from various evidentiary biological stains were also correctly typed. The successful application of the muCAE device to actual forensic STR typing samples is a significant step toward the development of a completely integrated STR analysis microdevice.     

法医物证DNA自动化检验技术体系的研究

目的建立自动化工作站同步提取不同种类涉案法医生物检材DNA的新方法。方法选用TECAN Freedom EVO100．4、75—2型自动化提取、加样工作站,采用磁珠法及Chelex-100法对各类涉案生物检材进行DNA提取、PCR扩增、毛细管电泳检测其STR分型,进行比较测试。在“全国公安机关DNA数据库应用系统”中建立并应用实验室信息管理系统（LIMS）模拟实施规范化DNA检案。结果1552份各类检材,采用工作站-磁珠法提取DNA效果最佳,STR检测成功率为95％,工作站-Chelex法为88％;二者分别与其手工提取法比较,成功率无明显差异。92个样本同期检测,自动化工作站较手工操作DNA检案时间可缩减1．25倍。结论工作站域珠法提取涉案检材DNA,可获得满意的STR分型结果。应用LIMS管控,可有效防控污染,明显提高检案效率及鉴定质量。     

2种陈旧骨骼、牙齿DNA纯化方法的比较

目的比较有机法+QIAquick纯化法和DNA IQ磁珠法对陈旧骨骼和牙齿DNA的纯化效果。方法选择10份陈旧骨骼和12份牙齿样本,进行消化后分别采用有机法+QIAquick纯化法和DNA IQ磁珠法进行提取纯化,进行DNA定量后用SinofilerTM试剂盒进行检测。结果 2种方法纯化的骨骼、牙齿DNA的IPC CT值无显著差异。有机法+QIAquick纯化法纯化的骨骼、牙齿DNA平均浓度分别为0.180ng/μL±0.068ng/μL和0.132ng/μL±0.027ng/μL,所有样品均获得全部基因分型。DNA IQ磁珠法纯化的DNA平均浓度分别为0.038ng/μL±0.028ng/μL和0.036ng/μL±0.007ng/μL,有5份骨骼和6份牙齿样本仅获得部分基因分型或未能分型。结论有机法+QIAquick纯化法对陈旧骨骼、牙齿DNA的纯化效果优于DNA IQ磁珠法。     

荧光标记STR分型技术检验腐败组织基因型

探讨腐败组织荧光标记STR分型检测技术的应用价值。应用含12个STR基因座及一个性别基因座的2个荧光标记的复合扩增系统,对40例1～6周的腐败肌肉提取的DNA进行扩增,用变性聚丙烯酰胺凝胶电泳,PE377测序仪分析基因型。所检测样本在12个STR基因座均扩增出特异性谱带,并可判定其基因型。荧光标记STR检测技术对腐败组织分型可靠,在实际检案中具有较高的应用价值。     

Typing of XY (male) genotype from malignant neoplastic tissue by the amelogenin-based sex test

DNA profiling of a cancer tissue can be problematic because of genomic instability. Here we have analyzed gastrointestinal cancer specimens from 46 males, of which seven (15%) showed aberrations in determination of gender by the widely used amelogenin test. The X-type amelogenin allele in all cases remained intact. All male tumor samples showing frequent autosomal loss of heterozygosity had a decreased signal of the Y allele from the amelogenin marker. When tested with an alternate set of primers for the amelogenin locus, the Y-type allele showed loss of heterozygosity in the same seven cases. However, when amplified with 15 Y-specific STR primers, all the cancerous tissue Y chromosomes seemed to be intact. These results indicate when malignant neoplastic tissue specimens are used, that amelogenin-based gender determination should be carefully interpreted.     

改良IPEP法用于痕量DNA检测的实验研究

目的探讨改良扩增前引物延伸(IPEP)法对痕量DNA样本STR检测分型的效果。方法用改良IPEP法对痕量样品DNA进行全基因组扩增(WGA),扩增产物用实时荧光定量PCR技术定量、用AmpFLSTR~ Indentifiler~试剂盒作基因型检测。结果该方法可增加模板DNA约200~1100倍。基因组DNA不低于0.025ng时,可获得15个STR基因座和Amelogenin性别基因座的分型结果。基因组DNA0.01~0.025ng时,可获得9个以上基因座的分型结果。结论改良IPEP法可有效提高痕量DNA样本STR分型检验的灵敏度,有较好的实用价值。     

A Y-chromosome STR marker should be added to commercial multiplex STR kits

Abstract:  Autosomal short tandem repeat (STR) analysis has become highly relevant in the identification of victims from mass disasters and terrorist attacks. In such events, gender misidentification can be of grave consequences, yet the list reporting amelogenin amplification failure using STR multiplex kits continues to grow. Presented here are three such examples. In the first case, we present two male suspects who demonstrated amelogenin Y-deficient results using two commercial kit procedures. The presence of their Y chromosomes was proven by obtaining a Y-haplotype. The second case demonstrated a profile from a third male suspect where only the Y homolog of the XY pair was amplified. In events such as mass disasters or terrorist attacks, timely and reliable high throughput DNA typing results are essential. As the number of reported cases of amplification failure at the amelogenin gene continues to grow, we suggest that the incorporation of a better gender identification tool in commercial kits is crucial.     

汗潜指印的STR分型检测在案件中的应用

目的探索案例中所涉及的汗潜指印DNA的提取和检验方法。方法采用Chlex-100法提取DNA,进行STR复合扩增,通过毛细管电泳检测荧光信号。结果案例中涉及的汗潜指印在ProfilerPlus试剂盒10个基因座的分型检测均获成功。结论含有汗潜指印的检材的发现和正确提取对最终检测成功至关重要。     

妇科肿瘤和乳腺癌组织常染色体和X染色体STR的突变分析

目的探讨妇科肿瘤组织和乳腺癌组织的法医学常用STR基因座突变类型和规律,以及显微切割技术在肿瘤组织法医学鉴定中的应用。方法应用Power Plex 21 System和Argus X-12试剂盒对62例乳腺癌患者,62例妇科恶性肿瘤患者,10例良性妇科肿瘤患者外周血、肿瘤组织和癌旁组织DNA样本进行复合扩增,获得STR分型,并选取存在突变的部分肿瘤组织进行显微切割。结果妇科恶性肿瘤患者外周血的STR分型与癌旁组织一致;46.77%的妇科恶性肿瘤组织中观察到4种STR突变类型,显著高于良性肿瘤的STR突变率(P0.01)和乳腺癌的STR突变率(P=0.009)。显微切割获得的间质细胞的STR分型与癌旁组织一致。结论本研究所检测的STR基因座在妇科恶性肿瘤组织中的稳定性较差,不适用于该系统肿瘤组织的法医学鉴定;显微切割技术可准确分离间质细胞,能够代表肿瘤来源个体的正常DNA分型,是解决此类案件法医学鉴定的一种有效方法。     

牛四核苷酸STR基因座的筛选和多态性分析

目的筛选阴影带出现率低且多态性较高的牛四核苷酸STR基因座。方法用Tandem repeats finder软件搜索牛基因组中的四核苷酸重复STR序列片段,用Primer Premier 5.0软件设计引物,然后扩增、电泳,筛选出符合要求的STR基因座,并对100份无关黄牛个体血样进行STR基因座分型。结果共筛选出6个具有多态性的牛四核苷酸重复STR基因座（B006、B007、B008、B022、B025、B026）,其100份无关黄牛个体血样的累积个体识别率和累积非父排除概率分别为0.99995和0.859591。结论本研究筛选出的6个四核苷酸STR基因座阴影带出现率低且多态性较高,可用于牛的个体识别和亲子鉴定的研究。