Population data for six X-chromosome STR loci in a Rio de Janeiro (Brazil) sample: Usefulness in forensic casework

This study presents data for the X-chromosome STR loci DXS7133, DXS7424, DXS8378, DXS6807, DXS7423 and DXS8377. In order to establish a database, unrelated individuals (males and females) from Rio de Janeiro were typed for the above loci. No significant differences were observed between allele frequencies in male and female samples (non-differentiation exact P values ≥ 0.156). Hardy-Weinberg equilibrium was tested in the female sample and no significant deviations were found. All six markers have shown to be highly polymorphic in our sample with gene diversities varying between 0.6797 for DXS7133, and 0.9260 for DXS8377. Pairwise linkage disequilibrium analysis did not allow discharging a possible association between DXS7133 and DXS7424 alleles in Rio de Janeiro population. Parameters of forensic interest, like PD_M, PD_F, Het_obs, Het_exp, were calculated for each locus. The high discrimination power estimated in both males and females, as well as mean exclusion chance in father/daughter duos and in father/mother/daughter trios, demonstrates the usefulness of these six markers in forensic investigation.     

复合扩增A10、C4基因座遗传多态性及法医学意义

目的　建立复合扩增A10、C4基因座的体系 ,研究其在法医学检验中的应用价值。方法　生物学样本用Chelex - 10 0的方法提取DNA ,荧光标记的特异性引物复合扩增A10、C4基因座 ,用ABI 310 0遗传分析仪对扩增产物进行检测分型。结果　A10、C4基因座各检出 6个等位基因 ,GD值分别为 0 .6 86 ,0 .84 6 .共检出 2 3种单倍型 ,其单倍型的个体识别率为 0 .9184。扩增女性DNA ,均无特异性扩增产物 ;调查 30个二代家系 ,均未观察到突变基因的存在。结论　A10、C4复合扩增体系多态性较高 ,对法医学中男女混合检材的个人识别及父系亲缘关系鉴定有较高的应用价值。     

Comparison of STR loci profiles obtained from extracted FTA discs using different DNA polymerases

Six commercially available DNA polymerases together with their respective buffers were compared as to their ability to generate profiles of commonly used short tandem repeat loci. Extracted FTA paper discs were used in two fluorescent multiplex PCRs containing the same number of units of DNA polymerase to amplify 21 STR loci and the resultant alleles were visualized after electrophoresis on a capillary sequencer. Significant differences were observed upon comparing the profiles: one polymerase failed to amplify larger alleles and presence of additional peaks varied according to the enzyme used. The use of hot-start polymerases did not affect the quality of the resultant profiles in this comparison.     

The mystery of shrinking heads

Shrinking heads as trophies are well known all over the world. Several forms of mummified human trophy heads were produced by different tribes, in addition not true or not traditional shrunken heads were put out. A well preserved shrunken head of unknown origin was examined by our group. Besides anatomy histological and DNA analysis of the mummified material was performed. Furthermore larvae connected to the hair were examined microscopically. Histology of the skin from the neck region showed cellular structures with cytoplasm and nucleus. The larvae were identified as from Pediculus humanis capitis, the human hair lice. Finally DNA analysis of the mummified head revealed a human female STR profile.     

触摸遗留人体生物检材DNA分型检验2例

1案例资料 1．1案例1 简要案情2007年7月至2008年2月，某市发生系列爆炸案，从现场提取自制导火线、捆绑爆炸装置用的绳结、旧棉花等可能留有犯罪嫌疑人脱落上皮细胞的检材。     

口腔拭子DNA检验的实时定量研究

目的寻求提高口腔拭子的DNA检验效率的方法。方法对来源于不同个体或同一个体不同擦拭次数的口腔拭子用Chelex-100或磁珠法提取的DNA用实时定量PCR技术进行定量,同时用Identifiler复合扩增系统在ABI3100遗传分析仪上对这些DNA样品进行STR分型。结果在建立的Identifiler系统8μl扩增体系中,3个月内的口腔拭子用Chelex-100法提取的DNA模板1μl量较3μl量扩增效果好,磁珠法提取的DNA模板用量大小对复合扩增检测影响较小。结论用棉签擦拭颊粘膜5次制备口腔拭子,取其头部的约1/4用200μlChelex-100法提取DNA,然后用1μl模板进行复合扩增,是提高口腔拭子的DNA检验效率的简便可行的方法,但陈旧口腔拭子用磁珠法提取更能保证复合扩增分型成功。     

荧光标记短片段STR复合扩增系统的法医学应用研究

目的解决严重降解(低于300bp)DNA检验问题,提高降解DNA的检出率。方法重新设计引物,减小扩增产物片段长度,用荧光标记短片段STR复合扩增体系进行DNA检验,扩增结果与用Identifiler试剂盒扩增出的结果进行比较。结果用荧光标记短片段STR复合扩增系统对实际案件中的高度降解DNA检材进行检验,可以获得满意分型。结论该系统可用于严重降解DNA检材的检验工作。     

亲子鉴定中STR位点数选择及其应用价值研究

目的对在亲子鉴定中STR位点数的选择及其鉴定应用价值进行研究。方法将CODIS13个STR位点分为四个观测组,观测对象包括排除亲权的母亲-孩子-假设父亲三人组合102例,以及肯定亲权的母亲-孩子-假设父亲三人组合100例,通过310遗传分析仪对荧光复合扩增产物进行分型检测。结果各STR观察组出现的最低排除指标数与各观察组累积非父排除概率(CPE)值成一定正相关性,CPE值超过99.99%的两个STR观察组其出现的最低排除指标数为三个,同时这两个STR观察组在肯定亲权的案例分析中,其亲子关系概率值(RCP)值都超过了99.99%。结论对于亲子鉴定中的STR位点检测系统,其非父排除指标应为三个以上,其累积非父排除概率(CPE)值达到99.99%时,就可以认为该STR位点检测系统具有了相关的鉴定应用价值。     

用Chelex100法及有机溶剂提取法联合提取DNA扩增STR基因座的比较研究

为了比较不同方法提取DNA扩增STR基因座的成功率 ,本文用Chelex10 0法及Chelex10 0法联合有机溶剂提取法分别提取性犯罪案件 6份血斑及 6份混合斑中精子DNA ,并用PE公司ProfilerPlus系统复合扩增 ,ABI 310型基因分型仪检测。结果表明 ,常规采用Chelex10 0法提取血斑及精斑等生物检材DNA作STR基因座检验失败或所检测的位点较少时 ,应对Chelex10 0法提取的DNA上清液再用有机溶剂提取法提取 ,可极大提高DNA检验成功率。采用本文建立的Chelex10 0法联合有机溶剂提取法 ,提高了PCR扩增阳性率 ,对实际检案很有帮助 ;在PCR扩增前应常规进行DNA定量检验 ,否则对于重要检材应进行梯度扩增。     

310型遗传分析仪的应用

使用ABI公司ProfilerPlus、Cofiler试剂盒及310型遗传分析仪(以下简称310)检验各类案件2000余起,简化了ABI公司推荐的检验步骤,节约了成本,缩短了检验时间,讨论分析常见问题并提出解决办法,使结果分析更为客观准确.