Y染色体单核苷酸多态性及其在刑事侦查中的应用价值

寻找和研究SNP已成为后基因组时代研究的重要内容和目标。Y染色体的拟常染色体非重组区段的SNP标记,是目前公认的研究早期人类进化和迁移以及法医学应用最理想的工具。Y染色体单核苷酸多态性（SNP）分型和检测方法的发展,决定了它能被广泛运用于刑事侦查当中。Y染色体的命名、标记和分类等技术分析方法有待进一步地发展,以提高其识别的规范性与稳定性。     

Inferring ancestral origin using a single multiplex assay of ancestry-informative marker SNPs

Tests that infer the ancestral origin of a DNA sample have considerable potential in the development of forensic tools that can help to guide crime investigation. We have developed a single-tube 34-plex SNP assay for the assignment of ancestral origin by choosing ancestry-informative markers (AIMs) exhibiting highly contrasting allele frequency distributions between the three major population-groups. To predict ancestral origin from the profiles obtained, a classification algorithm was developed based on maximum likelihood. Sampling of two populations each from African, European and East Asian groups provided training sets for the algorithm and this was tested using the CEPH Human Genome Diversity Panel. We detected negligible theoretical and practical error for assignments to one of the three groups analyzed with consistently high classification probabilities, even when using reduced subsets of SNPs. This study shows that by choosing SNPs exhibiting marked allele frequency differences between population-groups a practical forensic test for assigning the most likely ancestry can be achieved from a single multiplexed assay.     

Looming Issues for Scotland and the Union

The minor electoral gains for the Scottish National Party (SNP) in 2007, which made it the largest party but a minority Scottish Executive administration, have provoked a fundamental review of Scottish devolution. Political imperatives rather than reasoned argument seem to dominate the actions of those pushing for independence and/or greater powers for the Scottish Parliament. The renaming of the Scottish Executive by the SNP as the Scottish Government is creating confusion. The Scottish Executive's plans to move to independence are inadequate for the significance of the intended outcome. The unionist opposition parties could not agree to form a majority coalition but have launched a major review of devolution which includes the possibility of increased tax powers for the Scottish Parliament even when existing tax powers are not used. Federalism has been proposed by the Liberal Democrats and others but evidence from other states suggests that this is by no means a stable or certain solution.     

Y-chromosome lineages in São Tomé e Príncipe and Cabo Verde islands: Different input of European influence

The Y-chromosome haplogroup composition of the population of São Tomé e Príncipe and Cabo Verde Archipelagos was profiled by using 24 biallelic markers, and compared with populations from Europe, Africa and the Middle East. According to the traditional view, these archipelagos colonized by the Portuguese in the 15th century were settled mainly by West African slaves, with the addition of a minor fraction of male colonizers from Europe. Although the major proportion of the founding population of São Tomé e Príncipe cluster in haplogroup E3a (84.2%), very common among sub-Saharans, this lineage was observed at a frequency of only 15.9% in Cabo Verde. Haplogroups I, J and R1, characterized of populations of Europe and the Middle East account for more than half of the paternal lineages of Cabo Verdeans (53.5%). These West Eurasian haplogroups are found at a frequency of only 12.5% in the population of São Tomé e Príncipe. Our findings suggest that despite the sub-Saharan genetic background of these archipelagos, a relevant contribution of European paternal lineages is present in nowadays populations indicating that gene flow from multiple sources have been important in the formation of the diversity of the islanders, nevertheless with a different degree of admixture.     

荧光标记复合扩增毛细管电泳法在SNP分型中的应用

目的采用荧光标记复合扩增毛细管电泳法，对辽南地区汉族人群13个SNP进行等位基因频率调查，并评价其法医学应用价值。方法选择13个双等位基因SNP，应用荧光标记片段长度差异等位基因特异性复合扩增SNP分型方法，对辽南地区汉族人群进行群体调查。结果每个SNP纯合子为单一产物峰，杂合子则为长度不同的两个产物峰。不同位点扩增产物长度不同，根据产物长度和产物峰数量进行SNP分型，其结果与直接测序完全一致。同时获得辽南地区汉族人群13个SNP等位基因频率。结论采用荧光标记复合扩增毛细管电泳法进行SNP分型，方法简单实用，在法医学个人识别领域具有较高的应用。     

"Biological identikit": Development of a SNPs-panel for the analysis of forensic DNA phenotyping and ancestry

Personal identification in mass disasters and in crimes is essential for humanitarian, ethical and legal reasons. In these contexts, when individuals cannot be identified by standard forensic DNA analysis, the Forensic DNA Phenotyping and the analysis of the biogeographical ancestry could help. The aim of this study was to evaluate the potential of a new panel of 891 SNPs in predicting phenotypic traits and biogeographical origin to create a “biological identikit”. In addition to fresh biological material, old evidence found at the crime scene or extracted and long-term stored DNA were tested with 41 SNPs for phenotyping and 850 SNPs for ancestry. All the SNPs were successfully incorporated into a single two-step multiplex PCR reaction using the IonAmpliSeq ™ Library Plus and applied for massive parallel sequencing with the Ion S5 platform using up to 0.05 ng/µL of DNA. The analysis of the results was carried out with an in-house predictive algorithm and consulting 20 population databases. By comparing the results obtained with identikit or video-photographic surveys, it was possible to predict phenotype and ancestry with an accuracy greater than 90%. While these new markers cannot identify a specific individual, they can be a valuable investigative tool.     

31个SNP位点多重PCR扩增和芯片分型技术的建立及其法医学应用

目的对SNP基因分型芯片在个体识别中的应用价值进行研究。方法根据SNP不同等位基因的序列设计探针,制成分型芯片。采用4个复合PCR体系,用末端标记了Cy5的引物进行复合PCR扩增,产物与寡核苷酸探针进行杂交,根据杂交产生的荧光信号值确定样品在各SNP位点的基因型。将这一方法应用于109份样本的分型,根据基因型分布统计分析31个SNP位点的法医学应用价值。同时,进行家系调查和方法灵敏度分析。结果方法的灵敏度为1ng;所检测的31个SNP位点的累积个体识别率为0.9999999999979(偶合率为2.13×10-12),二联体亲子鉴定中累积非父排除率为0.9609,三联体亲子鉴定中累积非父排除率为0.9970。家系调查的结果表明,这些位点等位基因由亲代向子代的传递符合孟德尔遗传定律。结论上述31个SNP位点为中高信息量位点,适用于法医学个体识别,可作为当前STR系统的补充。     

利用RASSF1A位点检测母体血浆中胎儿SNP分型

目的探讨利用母体血浆中高甲基化RASSF1A位点进行胎儿SNP分型的应用价值。方法随机收集10个未孕健康妇女和45例不同孕期（早期5例、中期20例、晚期20例）孕妇的血样本及相应胎儿组织（绒毛组织、羊水、胎盘组织）;利用甲基化敏感限制性内切酶BstUI酶切后进行PCR,产物进行血细胞、血浆和胎儿组织（绒毛或胎盘）DNA RASSF1A序列的甲基化模式检测,并采用直接测序法对SNP rs4688725位点进行分型。结果经BstUI酶消化,RASSF1A序列在母体血细胞中均未检出,而在绒毛或胎盘组织中均能检出;在45名孕妇血浆中,RASSF1A序列均能被检出,且序列内的SNP分型与相应胎儿组织一致;在10名非孕妇女血浆中均未检出RASSF1A序列。结论母体和胎儿DNA中RASSF1A基因启动子区域的甲基化模式存在差异,可用于对母体血浆中的游离胎儿DNA进行SNP分型。     

Application of mtDNA SNP analysis in forensic casework

In this study six forensic cases are presented where the routine analysis of samples for short tandem repeats (STRs) failed. The sequencing of the mitochondrial hypervariable region I (HVR I) also failed. Nevertheless, it was possible to analyse the samples with mitochondrial DNA (mtDNA) single nucleotide polymorphisms (SNPs) via SNaPshot technique. The age of the analysed samples ranged from 2 months to 1400 years. Saliva-, blood-, sperm-, hair-, tooth- and bone-samples were investigated. Furthermore the mtDNA SNP analysis of a forensic case sample showing a mixed stain profile is presented. It was possible to discriminate two different haplogroups in this mixed-person stain. If compared to another mtDNA SNP profile that was found in a hair, the discriminating SNPs of the hair were as well found in the mixed-person stain.To disburden the SNP analysis in forensic casework, haplogroup assignment criteria and quality criteria for mtDNA SNaPshot analysis are announced.     

大麻遗传标记的法医学应用研究进展

大麻是大麻科大麻属一年生雌雄异株的草本植物,其内含有具有强烈成瘾性和麻醉性的四氢大麻酚(THC).大麻价格低廉、获取方便、且受到一些国家和地区合法化的影响,目前已成为滥用最广泛的毒品之一.因此,大麻植株的鉴定对于打击毒品犯罪、维护社会稳定具有重要意义.近年来,基于DNA遗传标记的大麻鉴定为案件侦破提供了新的技术手段,针...