Statistical analysis of DNA mixtures using peak area information and allelic drop out

A case of a woman killed in Perugia is reported. The woman was beaten to death and the body showed evidence of bites, kicks and punches. The request of the Court was to verify the presence of bites and if they belonged to humans. Morphological examination and genetic analysis with human Y-specific markers were performed in order to verify the origin of the bites. The DNA profile from the surrounded area of the traces was compared with the profile of the victim's husband (the suspect).The results showed a match between the profile of the suspect and that of the traces for all loci examined. Due to the fact that also other relatives of the husband's male lineage lived in the same house, it was not possible to identify the man who really contributed to the traces. Therefore, the analysis was implemented with autosomal STR markers, which showed a mixed genetic profile. In order to verify the number and the identity of the contributors, statistical analysis based upon peak area information was performed with Probabilistic Expert Systems.     

EA-YPredictor:基于Y-STR数据的家系特异性单倍群归属判别分析软件

目的Y染色体为男性所特有,其遗传标记蕴含着丰富的生物地理信息,故可溯源家系,在嫌疑人排查和追踪中发挥作用。Y-STR突变率较高,而Y-SNP突变率极低,几乎不会发生回复突变,所以后代男性群体携带祖先特有的Y-SNP。本研究期望通过现在我国Y库建设中通用的17个Y-STR的单倍型数据预测Y-SNP单倍群细支。方法基于前期观察,选取千人基因组计划III期中的513例东亚人群(中国及周边区域)作为基础数据集,在Java平台和Microsoft Excel软件框架下,以遗传距离计算和Y染色体进化树构建手段相联合研发Y-STR数据的家系特异性单倍群归属判别分析软件:EA-YPredictor。结果本研究揭示了15个单倍群大支下的核心单倍型。通过随机选取70个公开数据库样本,EA-YPredictor软件预测准确性达到92.8%(95%置信区间:[84.1%,97.6%])。结论在Y-SNP复合扩增检测尚无定论的情况下,本软件可基于二代测序样本对Y-STR数据库样本进行单倍群细支的准确预测,能适用于辅助家系单倍群判断。随着测序技术的不断换代和优化,更多高通量的Y-STR和Y-SNP数据补充将会使本软件进一步优化。此外,本软件对于Y数据库中Y-SNP遗传标记的筛查建库有一定指向作用。     

二代测序技术在Y染色体遗传标记分型中的法医学应用

法医遗传学领域常利用Y染色体的父系遗传特点,对非重组区遗传标记进行检测并用于亲缘关系鉴定、混合斑检测、家系排查以及种族推断等研究.目前毛细管电泳仍是应用最为广泛的检测技术,基于该技术的商业化检测试剂盒及数据分析处理系统十分成熟.随着生物信息量的增长,传统检测技术通量低的弊端逐渐显现,推动了法医DNA分型技术的革新.近年...     

DGGE技术检测小核核糖核蛋白多肽N基因rs220030位点的多态性

目的 分析小核核糖核蛋白多肽N(small nuclear ribonucleoprotein polypeptide N,SNRPN)基因SNP位点rs220030在中国汉族人群中的基因结构特征及多态性,获得群体遗传学资料.方法 应用变性梯度凝胶电泳(denatu^ng gradient gel electropho...     

Accumulation of population polymorphisms in the mitonuclear genome with probable adaptive effect to extreme environments as altitude for forensic purposes

We analyzed the accumulation of population polymorphism in 2504 individuals - nuclear genomes (nDNA) of 26 populations (81 genes associated to extreme environments) and 3295 mitochondrial genomes (mtDNA) of 47 populations with the aim to found mitonuclear relationship associated an extremes environment as altitude. For that, we use an algorithm developed by us to determine the accumulation of polymorphisms by segments in the genome and thus be able to perform the multivariate analysis to found SNPs differences and similarities among populations. The results showed in Peruvian population a statistically significant mitonuclear relationship for 113/293970 nDNA SNPs in 16/81 genes. In the case of the mtDNA, we found a statistically significant mitonuclear relationship for 6/22 mtDNA positions – Gene. Additionally for the Peruvian population, the MRPP3 had the greatest polymorphism contribution with respect to other populations. Then, these nDNA and mtDNA SNPs in genetically close populations to Peru can be applied to forensic genomic phenotyping to identify groups likely adapted to extreme conditions (such as altitude) or make individualization between low and high altitude populations.     

Population genetics of 30 insertion-deletion polymorphism in polish Populations

The Investigator DIPplex® kit (Qiagen) contains components for the simultaneous amplification and analysis of 30 biallelic autosomal InDels and amelogenin. The objective of this study was to estimate the diversity of the 30 markers in a Polish population sample (N = 389) and to evaluate their usefulness in forensic genetics. The DIPplex genotype distributions showed no significant deviation from Hardy-Weinberg rule expectations (Bonferroni corrected). The mean observed heterozygosity value is 0.4611, and the combined Matching Probability value is 1.08x10⁻¹³. The investigated marker set has been confirmed as a potential extension to standard STR - based kits or a separate informative system for individual identification and kinship analysis.     

A method to enable forensic genetic genealogy investigations from DNA mixtures

The presence of more than one DNA contributor in an evidentiary sample may preclude attempts to use forensic genetic genealogy to develop an investigative lead. To address this issue, we developed a workflow for deconvolution of SNP mixtures into single source profiles that are suitable for matching against a genealogical database. Using the method, two-contributor DNA mixtures assayed using a commercial SNP typing kit can produce informative match results for both major and minor contributors.     

AGCU Mini系统在法医学中的应用

目的考察及评价AGCU Mini系统在法医学实践中的应用价值。方法应用AGCU Mini系统检测12 775份陈旧血样,进行梯度DNA模板浓度分析,并与IdentifilerTM试剂盒检测结果进行比对,评价体系的检测成功率及方法的灵敏度。针对AGCU Mini系统中D19S253基因座,对699份浙江汉族无关个体进行多态性调查。结果 12 775份陈旧血样采用AGCU Mini试剂盒检测,12 885份(96.1%)分型成功,检测灵敏度为40pg(10μL体系),方法成功率及灵敏度均高于IdentifilerTM试剂盒。D19S253基因座共检出9个等位基因,频率范围为0.005 7～0.316 2,杂合度为0.814 0,多态性信息含量为0.772 9。结论 AGCU Mini系统可用于法医微量物证的STR分析,与相关试剂盒联合使用价值更高。     

Shifting Perspectives: Cognitive Changes Mediate the Impact of Romantic Relationships on Desistance from Crime

Although research regarding the impact of marriage on desistance is important, most romantic relationships during early adulthood, the period in the life course when involvement in criminal offending is relatively high, do not involve marriage. Using the internal moderator approach, we tested hypotheses regarding the impact of non-marital romantic relationships on desistance using longitudinal data from a sample of approximately 600 African American young adults. The results largely supported the study hypotheses. We found no significant association between simply being in a romantic relationship and desistance from offending. On the other hand, for both males and females quality of romantic relationship was rather strongly associated with desistance. Partner antisociality only influenced the offending of females. Much of the effect of quality of romantic relationship on desistance was mediated by a reduction in commitment to a criminogenic knowledge structure (a hostile view of people and relationships, concern with immediate gratification, and cynical view of conduct norms). The mediating effect of change in affiliation with deviant peers was not significant once the contribution of criminogenic knowledge structure was taken into account. The findings are discussed in terms of social control and cognitive accounts of the mechanisms whereby romantic relationships influence desistance.