X染色体遗传标记研究进展

随着人类基因组计划的进展,全面深入地了解个体和群体间基因组的变异或多态性已成为可能,并日益显示其重要性。X染色体遗传标记的遗传多态性较多地表现在短串联重复序列和单核苷酸的多态性。这类多态性有助于解释个体的表型差异、不同群体和个体对疾病,特别是对复杂疾病的易感性、以及对各种药物的耐受性和对环境因子的反应,因此受到临床及法医工作者的重视。本文收集了国内外X染色体遗传标记在临床疾病诊断及法医DNA工作者实践中的研究和应用资料,汇总报道了X染色体遗传标记的研究进展。     

67个X-SNP位点的分型检测和连锁不平衡检验

目的 筛选一组在中国汉族人群中具有法医学应用前景的X-SNP位点.方法 根据dbSNP和HapMap两个数据库提供的位点信息和频率数据从X染色体上筛选出67个候选X-SNP位点,采用多重PCR联合基质辅助激光解析电离飞行时间质谱技术检测中国汉族人群428名无关个体,获得67个候选X-SNP位点在中国汉族人群中的频率数据...     

An analysis of single and multi-copy methods for DNA quantitation by real-time polymerase chain reaction

The goal of this paper was to examine and compare two different commercially available approaches to the determination of the relative quantities of autosomal and Y chromosomal DNA using real-time PCR. One, Quantifiler^® Duo, utilizes a TaqMan^® assay with single copy probes for both autosomal human and Y quantification. The other method, Plexor HY^® utilizes a primer quenching assay with multi-copy probes for its quantification of autosomal human and Y chromosomal DNA. To test these approaches we have utilized the NIST Human DNA Quantitation Standard Reference Material 2372, a set of three different NIST human DNA quantification standards, to examine the precision, accuracy and sensitivity of the real-time PCR assays. We also examined data from both systems utilizing casework samples. The results show that both systems produced linear estimates for DNA quantity over a broad range of input DNA. However we did observe some apparent copy number effects when comparing the three different NIST standards which we attributed to issues with sequence variations in the different standards. Overall, the single copy approach provided better accuracy while the multi-copy approach produced better sensitivity. Thus the choice of which system to use should depend upon the goals of the user.     

Anthropological analyses of 30 insertion/deletion autosomal markers in five major ethnic groups of Pakistan

We investigated the forensic efficacy of the 30 insertion/deletion (Indel) markers included in the Qiagen Investigator® DIPplex kit in 529 Pakistani individuals from five major subpopulations in Pakistan (Punjabi, Pashtun, Sindhi, Saraiki, and Baloch). In the Sindhi population, the distribution of HLD81 and HLD97 alleles deviated from Hardy-Weinberg equilibrium after Bonferroni correction. The combined match probability ranged from 2.0E-12 (Pashtun and Baloch) to 1.0E-12 (Sindhi), and the mean paternity exclusion power varied from 0.995 (Punjabi, Sindhi, and Saraiki) to 0.996 (Pashtun and Baloch). The high combined power of discrimination (0.999 999 999 999 97) and low combined match probability (1.7E-12) for all subpopulations studied support the utility of the 30 Indel markers for forensic identification in the studied subpopulations. The allele frequencies of the Indel markers in the Pakistani subpopulations were compared with those from 18 other populations. The results show that the populations clustered according to geography. The subpopulations investigated in this work showed a close genetic relationship with others from Pakistan, as well as with South Central Asian and Middle Eastern populations. The results suggest that the Investigator^® DIPplex kit can be useful as a supplementary tool for human identification in the five Pakistani subpopulations investigated in this study.Supplemental data for this article is available online at https://doi.org/10.1080/20961790.2021.1933366 .     

Objective evaluation of similarity scores derived by Evofinder® system for marks on bullets fired from Chinese Norinco QSZ-92 pistols

In recent years, many studies have been conducted in the field of firearm identification with the objective of providing an objective method of evaluating the comparison of cartridge cases. However, less attention has been paid to the objective evaluation of bullet comparisons. In this study, 1 000 registered Chinese Norinco QSZ-92 pistols were used, and a database of 2 996 bullets was constructed. Both the receiver operating characteristic (ROC) curve and the score-based likelihood ratio method were used to objectively evaluate the similarity scores derived by the Evofinder^® system. The results indicate that this system has excellent ability to discriminate between the selected pistols. This paper proposes an objective evaluation method, which serves as a response to the ongoing debates regarding the foundation of the discipline.