DNA isolation success rates from dried and fresh wood samples of selected 20 tropical wood tree species for possible consideration in forensic forestry

The successful isolation of DNA (Deoxyribonucleic Acid) is essential for the investigation process of forestry molecular genetics. Samples used are usually retrieved either from soft or juvenile plant organs because of their excellent DNA source. However, in certain cases, aforesaid samples are hard to obtain, as for forensic purposes. Alternatively, woods possess potential as alternative source of DNA whose extraction method has been developed with varying degrees of success. However, to date, effectiveness on tropical wood grown in Indonesia has not been widely reported. Therefore, objective of this study was to compare the results of DNA isolation of various dried and fresh wood samples by using two isolation methods: Cetyl Trimethyl Ammonium Bromide (CTAB) and Qiagen DNeasy Plant Mini Kit (QDPMK). Extraction results were visualized in agarose gels and quantified using Nanophotometer NP80 Implen which were then amplified using two universal primers: ITS and rbcL for detecting DNA signals. Extraction results from dried wood indicated no visualization in the gel, while fresh wood samples showed thick smeared bands on both extraction methods. Quantity test results denoted higher concentration in CTAB-extracted samples compared to samples extracted using QDPMK, in both types of samples, even though both resulted in optical density ratios outside the range of purity (λ260/280: 1,8–2,0 and λ260/230: 2,0, respectively). Success rates of ITS and rbcL primary amplification in dried wood samples were quite low yet outputs from the two methods did not differ significantly. Meanwhile, outcome of ITS and rbcL amplification on fresh wood samples had a fairly high success.     

痘苗病毒SYBR GreenⅠ荧光定量PCR检测方法的建立与应用

为实现痘苗病毒的快速检测,根据痘苗病毒TA27L基因设计引物,经各项条件优化后,建立痘苗病毒SYBR GreenⅠ荧光定量PCR检测方法,同时将PCR扩增的TA27L基因克隆至pMD18-T载体,将测序正确的重组质粒作为标准品进行敏感性、特异性和重复性试验。结果显示,所建立方法的Ct值与标准品在7.58×10^9~7.58×10^2copies/μL范围内呈良好线性关系,R^2为0.997,斜率为-3.175,检测下限为75.8copies且具有良好的特异性。临床样本检测结果表明该方法较普通PCR方法的检出率更高。结果表明,建立的痘苗病毒SYBR GreenⅠ荧光定量PCR检测方法为痘苗病毒及其相关基因重组毒株的生物学特性研究提供了必要的技术手段。     

犬新孢子虫不同靶基因PCR检测方法的比较

为筛选出检测犬新孢子虫更为特异、敏感的PCR方法,分别以MAG1、SAG1和Nc5为靶基因进行PCR检测,并从敏感性、特异性和临床样本检出率等方面进行了比较。结果显示,以Nc5为靶基因的PCR方法敏感性最高,最小检测DNA量为17.8fg/μL;以MAG1为靶基因的PCR方法敏感性最低,最小检测DNA量为17.8pg/μL;而以SAG1为靶基因的PCR方法的最低检测量为178fg/μL;3种靶基因引物均扩增不出刚地弓形虫、牛瑟氏泰勒虫、猪附红细胞体等基因片段,具有较好的特异性;对28份已攻犬新孢子虫标准株的BALB/c小鼠组织样本的检测结果表明,以Nc5基因设计的引物检出率最高,为75.0%(21/28),明显高于SAG1基因的67.9%(19/28)和MAG1基因的53.6%(15/28)。本试验为新孢子虫病的诊断及流行病学调查提供了更为敏感、特异的检测技术。     

191名白山市汉族CODIS系统9个STR位点群体遗传学调查

目的　白山汉族CODIS系统 9个STR位点基因频率调查及其法医学应用 ;　方法　实验样本从 191位无相关白山市汉族个体获取 ,采用PCR复合扩增及 310遗传分析仪自动基因分型 ;　结果　这 9个STR位点均为高识别率位点 ,同重庆汉族人群群体遗传学数据比较显示有显著性差异 ;　结论　基因频率适合于白山汉族人群同一性概率及亲子鉴定概率计算 ;中国南北方汉族在个体识别及亲子鉴定概率计算时应采用本民族自己的等位基因频率。     

Y染色体A10 STR基因座在中国汉族群体中的多态性

目的获得A10基因座在中国汉族人群的多态性资料.方法用Chelex100方法提取100名无关个体汉族男性血痕DNA,利用荧光标记引物进行PCR扩增结合ABD377测序仪检测扩增产物.结果在A10基因座中国汉族人群发现6个等位基因,等位基因频率为0.01～0.48,GD值为0.6505.     

武汉汉族6个STR位点多态性研究

应用PCR及PAGE电泳技术对武汉汉族人群作DIS1656、D2S441、DHFRP2、D8S1132、D10S2325、DXS6804等STR位点进行遗传学多态性调查,结果DIS1656、D2S441、DHFRP2、D8S1132、D10S2325位点分别检出基因10,8,5,10,11个,分别检出基因型42、26、13、38、44个;DXS6804女性检出5个等位基因型,14个基因型,男性检出7个等位基因.经检验,6个STR基因座基因型分布均符合Hardy-Weinberg平衡,累积个人识别能力为0.99999987,累积非父排除率为0.9939.DIS1656等6个STR均属高杂合度,高鉴别能力的遗传标记系统,在法医学个人识别和亲子鉴定中有较高实用价值.     

Quantifiler observations of relevance to forensic casework

The Quantifiler (QF) kit is regularly used by forensic scientists for DNA quantitation. We performed in-house validation studies which revealed some interesting observations. The QF standard displayed a two-fold difference between two different lot numbers which suggests that every standard should be tested prior to use. The Promega K562 DNA standard works well with the QF kit. c. 41% of samples that inhibited the internal PCR control (IPC) system within the QF kit still produced good Profiler Plus reactions. QIAquick was effective at removing inhibitors. The presence of dyes within casework samples were observed not to inhibit QF amplifications. Template DNA greater than 100 ng/muL appeared to inhibit the IPC. Close to identical concentration results were obtained when alternative analysis settings were used. These validation findings will assist DNA processes involved in forensic casework.     

基于等位基因特异性PCR原理建立的SNP分型新方法

目的建立一种新方法,对多个单核苷酸多态性(singlenucleotidepolymorphism,SNP)位点进行分型。方法基于等位基因特异性PCR原理,采用荧光标记复合扩增和毛细管电泳技术,根据PCR片段长度差异进行分型。选择SNP位点共11个,每个SNP位点设计两条长度不同、3’末端分别与SNP两个等位基因碱基配对的上游引物,同时为了增加特异性,在两条等位基因上游引物的3’末端第3或第4位碱基人为引入错配。在距离上游引物100～300bp范围内的合适位置,设计下游共用引物,并进行荧光标记。所有位点经过复合扩增后,PCR产物经ABIPrismTM310型遗传分析仪电泳分离,确定每个SNP的基因型。结果每个SNP位点纯合子为单一产物峰,杂合子则为长度不同的两个产物峰。不同的SNP位点扩增产物长度不同,根据产物长度和产物峰的数量进行SNP分型,一次完成11个SNP位点分型,其结果与直接测序完全一致。结论荧光标记复合扩增片段长度差异等位基因特异性PCR法是一种简单快速而有效的SNP分型新方法。     

快速PCR仪与普通PCR仪扩增效果的比较研究

目的比较快速PCR仪与普通PCR仪的扩增效果。方法浓度为0.1、0.05、0.025、0.0125、0.0063ng/μL的9947A标准品各取样100例,采用Identifiler Plus试剂盒构建扩增体系,其中50例在普通PCR仪(9700型扩增仪)上进行扩增,50例在快速PCR仪(Speed cycler2扩增仪)上扩增,3500x L型遗传分析仪检测,对比每种浓度组两种扩增仪的检验结果。结果两种PCR仪的检出率均无差异(P0.05)。但当9947A的浓度为0.0125、0.0063ng/μL时,普通PCR仪检验样本的STR基因座检出数(13.7±1.0;11.3±1.5)均高于快速PCR仪(13.1±1.3;9.9±1.9),差异有统计学意义(P=0.029;P0.001);当9947A的浓度为0.1、0.05、0.025 ng/μL时,普通PCR仪检验样本的图谱峰高(18931±4625;13437±3165;5752±1344)均高于快速PCR仪(16929±4034;11815±4120;4865±1401),差异有统计学意义(P=0.023;P=0.030;P=0.002)。结论快速PCR仪可在较短的时间内达到与普通PCR仪相当的检出率,适合于实际案件中的应用;普通PCR仪检验获得的STR分型结果质量可能更高。     

Validation of the AmpF?STR SEfiler Plus™ PCR Amplification kit for forensic STR analysis

Validation of the AmpF?STR^® SEfiler Plus™ PCR Amplification kit with 29 and 30 PCR cycles for forensic STR analysis demonstrated that the kit had fewer artefacts than the AmpF?STR^® SGM Plus™ kit (28 PCR cycles). The SEfiler Plus kit was more sensitive and devoid of colour artefacts, but showed more stutters, drop-ins, drop-outs and allelic imbalances.