Development of multiplex PCRs for evolutionary and forensic applications of 37 human Y chromosome SNPs

This work describes an efficient and rapid test for typing 37 single nucleotide polymorphisms (SNPs) of the non-recombining region of Y chromosome (NRY) from a minimal amount of DNA using six PCR multiplexes. Markers were drawn following a hierarchical strategy based on the phylogenetic tree of Y chromosome proposed by the Y Chromosome Consortium [The Y Chromosome Consortium, A nomenclature system for the tree of human Y-chromosomal binary haplogroups, Genome Res. 12 (2002) 339-348]. Two multiplexes--arbitrarily named MY1 and MY2--were developed to explore the basal branches of the tree encompassing all the major clades A-R: MY1 for markers M35, M89, M172, M170, M9, M173, M45 and MY2 for markers M52, M216, M174, M181, M201, M91, M96, M214. Four multiplexes able of typing the more superficial branches typical of most frequent European haplogroups E3b, J2, R1 and I, were also developed and named MY-E3b (M78, M107, M224, M165, M148, M81), MY-J2 (M158, M68, M47, M102, M137, M67), MY-R1 (M17, M269, M18, P25, SRY10831.2) and MY-I (M72, M223, M26, M21, M161). SNP genotyping was carried out by hot-start PCR amplification with primers yielding fragments between 63 and 210 nucleotides, followed by minisequencing reaction based on dideoxy single-base extension and capillary electrophoresis of extension products. The sequential application of these multiplexes is a robust and effective resource for typing the most frequent European Y-SNP haplogroups, and appears to be suitable for forensic purposes and evolutionary studies.     

Inferring the population of origin of DNA evidence within the UK by allele-specific hybridization of Y-SNPs

Marked differences in Y-SNP allele frequencies between continental populations can be used to predict the biogeographic origin of a man's ancestral paternal lineage. Using 627 samples collected from individuals within the UK with pale-skinned Caucasian, dark-skinned Caucasian, African/Caribbean, South Asian, East Asian or Middle Eastern appearance we demonstrate that an individual's Y-SNP haplogroup is also strongly correlated with their physical appearance. Furthermore, experimental evaluation of the Marligen Signet Y-SNP kit in conjunction with the Luminex 100 detection instrument indicates that reliable and reproducible haplogrouping results can be obtained from 1 ng or more of target template derived from a variety of forensic evidence types including, blood, saliva and post-coital vaginal swabs. The test proved highly male-specific with reliable results being generated in the presence of a 1000-fold excess of female DNA, and no anomalous results were observed during degradation studies despite a gradual loss of typable loci. Hence, Y-SNP haplogrouping has considerable potential forensic utility in predicting likely ethnic appearance.     

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。     

云南白族群体Y-STR及Y-SNP关联性探讨

目的探讨Y-STR与Y-SNP单倍群间的关联性及其法医学应用价值。方法用Y-filer的17个Y-STR基因座及6个Y-SNPs（M122、M95、M9、M130、M119和M45）对云南白族146名无关男性个体样本进行检测。结果①17个Y-STR基因座构成的单倍型在146名男性个体中共检出114种单倍型,其中93种仅出现于一名个体中。②6个Y-SNPs在白族中的频率为4.1%～47.3%,其中O3-M122频率最高,占47.3%。③综合两类遗传标记结果,出现于2名或2名以上个体的21种Y-STR单倍型中,有5种其Y-SNP不同;分别只有一个Y-STR基因座分型不同的29对单倍型中,有8对其Y-SNP分别不同。Y-SNP单倍群间部分Y-STR基因座等位基因频率分布存在一定差异。结论 Y-STR单倍型相同或相近的个体间其Y-SNP分型可不相同,结合两者进行检测分析对于男性嫌疑人家系排查具有重要意义。     

淮海战役士兵遗骸的Y染色体遗传类型鉴定

目的鉴定淮海战役士兵遗骸的Y染色体遗传类型,为寻找其父系亲属提供线索。方法采用古DNA的方法提取遗骸DNA,使用Yfiler试剂盒进行17个Y-STR基因座的复合扩增,推测样本的单倍群,并根据最新Y染色体谱系树挑选Y-SNP位点进行精细分型,再基于Y-SNP和Y-STR数据进行共享单倍型分析,获得与遗骸遗传关系最近的现代个体信息。结果 8份男性样本中的17个Y-STR基因座总共观察到8种Y-STR单倍型,进一步Y-SNP分析得出6种Y-SNP单倍群,分别是O2a1-M95+、O1a1-P203+、O3*-M122+/M234-、D1-M15+、C3*-ST和R1a1-M17+。结论本次对淮海战役士兵遗骸进行的Y染色体遗传类型鉴定对于推断陈年检材的地理来源具有一定的借鉴价值。     

济南汉族群体5个Y-SNP位点的多态性分析

目的 探讨济南汉族群体5个Y-SNP位点的多态性并评价其在法医学中的应用.方法 采用片段长度差异等位基因特异性PCR(fragment length difference allele specific PCR,FLDAS-PCR)对济南汉族群体共103名男性无关个体5个Y-SNP标记(M89、M9、M122、M134...     

Y-SNP在法庭科学中的应用

本文介绍了Y-SNP的遗传特性、在世界特别是在东亚人群中的分布特点,以及在法庭科学中应用的研究做一综述,旨在利用现场罪犯遗留生物学检材的Y-SNP检测来推测其人种或地理来源,为案件调查提供帮助.     

Classification of the Y-haplogroup distributions of Western Eurasian populations using a self-learning algorithm

The understanding of historical relationship between populations is a core aspect of human population history studies. We have compared the frequency of 18 different Y-SNP haplogroups in 90 Western Eurasian populations. Classification of haplogroup distribution vectors using a new self-learning classification algorithm so called “self-organizing cloud (SOC)” proved to be an effective tool to identify population groups, which share common paternal genetic features. By means of the algorithm, we have determined 10 different classes of populations based on the similarity of haplogroup composition. The analysis showed that paternal genetic markers tend to reflect geographical proximity of populations better than linguistic relationship, although certain Y-SNP haplogroups have relatively good correlation with specific language families. These observations are based on the comparative analysis of the Hg distributions of contemporary populations may reflect demographic history of them in the past.     

Analysis of global variability in 15 established and 5 new European Standard Set (ESS) STRs using the CEPH human genome diversity panel

The CEPH human genome diversity cell line panel (CEPH-HGDP) of 51 globally distributed populations was used to analyze patterns of variability in 20 core human identification STRs. The markers typed comprised the 15 STRs of Identifiler, one of the most widely used forensic STR multiplexes, plus five recently introduced European Standard Set (ESS) STRs: D1S1656, D2S441, D10S1248, D12S391 and D22S1045. From the genotypes obtained for the ESS STRs we identified rare, intermediate or off-ladder alleles that had not been previously reported for these loci. Examples of novel ESS STR alleles found were characterized by sequence analysis. This revealed extensive repeat structure variation in three ESS STRs, with D12S391 showing particularly high variability for tandem runs of AGAT and AGAC repeat units. The global geographic distribution of the CEPH panel samples gave an opportunity to study in detail the extent of substructure shown by the 20 STRs amongst populations and between their parent population groups. An assessment was made of the forensic informativeness of the new ESS STRs compared to the loci they will replace: CSF1PO, D5S818, D7S820, D13S317 and TPOX, with results showing a clear enhancement of discrimination power using multiplexes that genotype the new ESS loci. We also measured the ability of Identifiler and ESS STRs to infer the ancestry of the CEPH-HGDP samples and demonstrate that forensic STRs in large multiplexes have the potential to differentiate the major population groups but only with sufficient reliability when used with other ancestry-informative markers such as single nucleotide polymorphisms. Finally we checked for possible association by linkage between the two ESS multiplex STRs closely positioned on chromosome-12: vWA and D12S391 by examining paired genotypes from the complete CEPH data set.     

Y-chromosomal SNP haplotype diversity in forensic analysis

Many Y-chromosomal single nucleotide polymorphisms (SNPs) are now available. The haplogroups which they define are highly non-randomly distributed among populations, and could contribute much to population-of-origin prediction from DNA. If this potential is to be exploited in forensic analysis, high-throughput, parallel methods are required for Y-SNP typing.     

Case report: Identification of skeletal remains using short-amplicon marker analysis of severely degraded DNA extracted from a decomposed and charred femur

Applying two extraction protocols to isolate DNA from a charred femur recovered after a major forest fire, a range of established and recently developed forensic marker sets that included mini-STRs and SNPs were used to type the sample and confirm identity by comparison to a claimed daughter of the deceased. Identification of the remains suggested that the individual had been dead for 10 years and the DNA was therefore likely to be severely degraded from the combined effects of decomposition and exposure to very high temperatures. We used new marker sets specifically developed to analyze degraded DNA comprising both reduced-length amplicon STR sets and autosomal SNP multiplexes, giving an opportunity to assess the ability of each approach to successfully type highly degraded material from a challenging case. The results also suggest a modified ancient DNA extraction procedure offers improved typing success from degraded skeletal material.     

Developmental validation of 15 X chromosomal short tandem repeat markers

The use of X chromosomal short tandem repeat (STR) markers has been greatly increasing in the forensic setting. Using guidelines set forth previously for the validation of autosomal and Y STRs, aspects of the feasibility of routine X chromosomal STR use were evaluated. Two mini-X chromosomal STR multiplexes capable of amplifying 15 total markers were developed and utilized to determine allele nomenclature, allele/genotype frequencies, mutation rates, and linkage between markers. Additionally, a concordance study between these multiplexes and a commercially available kit was performed. Here, the authors present an overview of this extensive developmental validation study.     

Using STR,MiniSTR and SNP markers to solve complex cases of kinship analysis

In complex kinship investigation, miniSTRs and SNPs have been frequently used in order to increase the likelihood ratio (LR), when the results obtained for the most commonly used STR multiplexes were not informative enough. In this work, we describe the results obtained when using a battery of 23 STRs, 3 miniSTRs and 52 SNPs to investigate three complex paternity cases where the father was not available, and one paternity case with bone samples, from which no results could be obtained for STRs (including the 3 miniSTRs, D10S1248, D14S1434 and D22S1045). In all cases, the additional information provided by the SNPforID 52plex identification panel was enough to achieve conclusive results.     

Routine Y-STR typing in forensic casework

In the field of molecular diagnosis, forensic casework analysis is one of the most demanding investigations, due to its social impact. Optimization of DNA typing multiplex reactions with identical cycling conditions as those required by autosomal short tandem repeats (STR) multiplex reduces errors, and saves time and reagents. Previously, we validated a five Y-STRs set, all of them generating single band patterns. This work reports the optimization of combined multiplexes, a triplex (DYS19, DYS390 and DYS391) and a duplex (DYS392 and DYS393), that can be amplified in identical cycling conditions as those required by commercially available multiplex autosomal STR kits. In addition both Y chromosome multiplexes can be combined for co-injection on a capillary electrophoresis based automated sequencer. Statistical attributes of the haplotypes of the five Y-STR investigated were evaluated in unrelated males from different metropolitan areas of Argentina. This system was successfully used for investigating more than 350 forensic routine cases in our country.     

Paternity investigation experience with a 40 autosomal SNP panel

With both the SNPforID and the Kidd panels of autosomal SNPs available, we selected the 40 most informative and population-independent SNPs from both these sets for evaluation in paternity testing and as a prelude for forensic human identification.We used the published primer sequences and constructed PCR multiplexes for genotyping using the SNaPshot assay. Fifty trios and 50 duos previously analysed using conventional autosomal STR markers were re-analysed using the 40 SNPs. We report our findings regarding the practical use of these markers including unexpected mutations which impacted significantly on the use of this panel.     

Validation of a microchip electrophoresis system as a DNA amplification control

As part of the normal procedure in a forensic DNA laboratory, a quality control step of the amplified DNA is often implemented to ensure the correct amplification of the sample before it is analysed in downstream applications. A validation study was undertaken to investigate a new microchip electrophoresis system (MultiNa, Shimadzu Corporation) claiming high resolution and sensitivity compared to routine polyacrylamide gel electrophoresis (PAGE). An array of STR multiplexes (AmpFISTR™ SGM+, GenePrint^® FFFL, PowerPlex™ 16, PowerPlex™ Y, an in-house Y-STR multiplex and AmpFISTR™ Profiler) was tested under both standard and low copy number PCR parameters to evaluate the accuracy, reproducibility and sensitivity of this technique. These tests showed that the microchip system did not have improved sensitivity compared to PAGE though had increased resolution and high reproducibility between samples.     

Y染色体STR的银染复合扩增

目的建立一套Y染色体STR的复合扩增体系,检测中国藏族人群的单倍型分布。方法利用复合扩增的方法扩增DYS434、DYS443和DYS456三个基因座,利用聚丙烯酰胺凝胶电泳银染进行分型,检测西藏藏族101名无关男性个体单倍型分布。结果三个基因座在藏族样本中分别检测出4、4、6个等位基因,共检测出31种单倍型,其单倍型的变异度是0.9481,标准误为0.0049。结论Y-STR的复合扩增在法医学的亲权鉴定和个人识别中有重要的作用。     

DNA mixtures in forensic casework: a 4-year retrospective study

Occasionally interpretation guidelines from validation studies are difficult to apply to real forensic casework, especially in the case of mixed samples. Exogenous contamination, an unknown number of contributors or unbalanced proportion of each one in the sample and a varied degree of degradation of the biological materials, contribute to the difficulties in the interpretation of sample profiles. In this paper we have reviewed all the mixed genetic STR profiles encountered in our laboratory over 4 years (1997-2000) and evaluated the problems in the interpretation of the results. From 1547 criminal cases with 2424 samples typed, 163 showed a mixed profile (6.7%). We have observed that occasionally, a mixture appeared in the same sample with one multiplex amplification kit (e.g. Blue) and not with another (e.g. Green). From our results, it can be suggested that technical characteristics of the different fluorochrome groups in the multiplexes override the molecular characteristics of each STR in their capacity to detect mixtures.     

New multiplexes for Europe-amendments and clarification of strategic development

Recently, the ENFSI/EDNAP groups issued advice on the design of the next generation of STR multiplexes in order to encourage standardisation within Europe. As the result of collaborative experimentation within the EDNAP group, we demonstrated that the low molecular weight STRs had substantial benefits to detect degraded samples. We subsequently recommended adoption of three new mini-STR loci to improve the success rate of degraded DNA markers, concurrent with the reduction in size of the existing STR markers in current use. This also improves the discriminating power of the system which is important to improve the power of national DNA databases. Subsequent discussions have occurred with manufacturers and members of the ENFSI/EDNAP groups. Because significant time and investment is required to develop new multiplexes of 13+ STR loci, manufacturers indicated that it would be preferable to adopt a staged approach. Two differing, but parallel strategies have now emerged. The first strategy employs a 13 STR loci multiplex incorporating three mini-STRs into the current multiplex test. The second strategy employs a multiplex of six high molecular weight STRs (in current use), modified to provide smaller amplicons combined with an additional two loci of high discriminating power. Eventually, the two strategies will converge to provide a single multiplex of 15 STR loci. The process will be guided by the ENFSI/EDNAP groups.