Utilizing Short Tandem Repeats (STRs) as a Resolving Matrix in Parental Dispute DNA Analysis

Interest in DNA analysis using short tandem repeats (STR) as finger printing tools in forensic medicine has gained tremendous application, as expression of these nuclear factors have enhanced forensic examination. Here we used this Biochemical characterization after conventional extraction process, polymerase chain reaction (PCR), gel electrophoresiss and a sequencer to distinguish and resolve parental dispute. The differential migration of labeled DNA fragments which attains excitation energy with a laser elicits fluorescent light of different wavelength depending on the dye used. A data collection software (Genemapper) collects raw data (spectrograph) and converts it to an electropherogram that is interpreted. By comparing the DNA profiles, inclusion and exclusion criteria were elucidated to resolve disputes. The inherent discriminating power of STRs used in analysis enhances resolution of cell mixtures, genetic aberration, substantiation of tissue origin and provides genetic distinction which is a robust and reliable approach in resolving parental disputes.

Identification and characterization of short tandem repeats in the Tibetan macaque genome based on resequencing data

The Tibetan macaque, which is endemic to China, is currently listed as a Near Endangered primate species by the International Union for Conservation of Nature （IUCN）（2017）. Short tandem repeats （STRs） refer to repetitive elements of genome sequence that range in length from 1-6 bp. They are found in many organisms and are widely applied in population genetic studies. To clarify the distribution characteristics of genome-wide STRs and understand their variation among Tibetan macaques, we conducted a genome-wide survey of STRs with next-generation sequencing of five macaque samples. A total of 1 077 790 perfect STRs were mined from our assembly, with an N50 of 4 966 bp. Mono-nucleotide repeats were the most abundant, followed by tetra- and di-nucleotide repeats. Analysis of GC content and repeats showed consistent results with other macaques. Furthermore, using STR analysis software （IobSTR）, we found that the proportion of base pair deletions in the STRs was greater than that of insertions in the five Tibetan macaque individuals （P〈0.05, t-test）. We also found a greater number of homozygous STRs than heterozygous STRs （P〈0.05, t-test）, with the Emei and Jianyang Tibetan macaques showing more heterozygous loci than Huangshan Tibetan macaques. The proportion of insertions and mean variation of alleles in the Emei and Jianyang individuals were slightly higher than those in the Huangshan individuals, thus revealing differences in STR allele size between the two populations The polymorphic STR loci identified based on the reference genome showed good amplification efficiency and could be used to study population genetics in Tibetan macaques. The neighbor-joining tree classified the five macaques into two different branches according to their geographical origin, indicating high genetic differentiation between the Huangshan and Sichuan populations. We elucidated the distribution characteristics of STRs in the Tibetan macaque genome and provided an effective method for screening polymorphic STRs. Our results also lay a foundation for future genetic variation studies of macaques.

Mapping short tandem repeats for liver gene expression traits helps prioritize potential causal variants for complex traits in pigs

Background:Short tandem repeats(STRs)were recently found to have significant impacts on gene expression and diseases in humans,but their roles on gene expression and complex traits in pigs remain unexplored.This study investigates the effects of STRs on gene expression in liver tissues based on the whole-genome sequences and RNA-Seq data of a discovery cohort of 260 F6 individuals and a validation population of 296 F7 individuals from a heterogeneous population generated from crosses among eight pig breeds.Results:We identified 5203 and 5868 significantly expression STRs(eSTRs,FDR<1%)in the F6 and F7 populations,respectively,most of which could be reciprocally validated(π1=0.92).The eSTRs explained 27.5%of the cisheritability of gene expression traits on average.We further identified 235 and 298 fine-mapped STRs through the Bayesian fine-mapping approach in the F6 and F7 pigs,respectively,which were significantly enriched in intron,ATAC peak,compartment A and H3K4me3 regions.We identified 20 fine-mapped STRs located in 100 kb windows upstream and downstream of published complex trait-associated SNPs,which colocalized with epigenetic markers such as H3K27ac and ATAC peaks.These included eSTR of the CLPB,PGLS,PSMD6 and DHDH genes,which are linked with genome-wide association study(GWAS)SNPs for blood-related traits,leg conformation,growth-related traits,and meat quality traits,respectively.Conclusions:This study provides insights into the effects of STRs on gene expression traits.The identified eSTRs are valuable resources for prioritizing causal STRs for complex traits in pigs.

ALLELE DISTRIBUTION OF FIVE X-CHROMOSOME SHORT TANDEM REPEAT LOCI IN EWENKE POPULATION OF NORTH CHINA

Objective To study the allele genetic polymorphism of five short tandem repeat （STR） loci on X-chromosome in Ewenke population of north China and to provide basic data for forensic identification. Methods Genomic DNA was extracted from EDTA-whole blood of Ewenke population by Chelex-100. The DNA samples were amplified by PCR and were analyzed by polyacrylamide gel electrophoresis and silver staining. The sequence length variations of DXS6799, DXS8378, DXS101, HPRTB, and DXS6789 loci on X-chromosome in 98 unrelated Ewenke individuals were investigated. Results All five loci analyzed showed high polymorphism and genetic stability. The data of the five X-chromosome STR loci in Ewenke ethnic group of China was in accordance with Hardy-Weinberg equilibrium by Chi-square test. Conchusion Allele polymorphism of five X-chromosome STR loci can be used as a genetic marker for forensic identification and population genetic research.

CNV-seq结合STR技术在稽留流产遗传学病因分析中的应用

目的 本研究旨在评估将低深度全基因组拷贝数变异测序(copy number variation sequencing, CNV-seq)技术与短串联重复序列(short tandem repeat, STR)技术联合应用于稽留流产患者流产组织遗传学病因分析的效果。方法 收集2019年1月至2022年11月期间因“胚胎停育”而终止妊娠的49例稽留流产患者进行CNV-seq技术和STR分型技术的联合检测。结果 研究发现孕妇流产次数≥2次组的胚胎染色体异常率明显高于流产次数<2次组,差异有统计学意义(62.1%vs 30.0%,P<0.05),而高龄孕妇组与非高龄孕妇组的胚胎染色体的异常率差异无统计学意义(70%vs 66.7%,P>0.05)。在49例流产物中,CNV-seq结合STR技术共检出34例染色体异常,检出率为69.4%(34/49)。其中染色体数目异常的有20例,包括13例非整倍体,5例多倍体(STR技术)和2例嵌合体;染色体结构异常共有14例,其中5例检出为致病性CNV。此外,还检测到了10例临床意义不明(variants of uncertain significance,VUS)的CNV。结论 将低深度CNV-seq技术与STR技术相结合,可以有效地弥补稽留流产的染色体核型分辨率低和培养难度大等缺点,并提高检测稽留流产胚胎异常染色体的能力,明确稽留流产的遗传学病因,为再次妊娠提供更准确的指导。

A NORTHWEST DATABASE MODEL OF SHORT TANDEM REPEAT LOCI IN FORENSIC MEDICINE

Objective To establish the northwest database of short tandem repeat(STR) loci in forensic medicine. Methods Bloodstains or whole blood samples were collected from the unrelated prisoners in Xi'an city. Genetic distribution for 13 STR loci and amelogenin locus were determined in prisons based on GeneScan. One primer for each locus was labeled with the fluorescent by 5 FAM, JOE, or NED. The forensic database were generated by using multiple amplification, GeneScan, genotype, and genetic distribution analysis. Results 113 alleles and 302 genotypes were observed, with the corresponding frequency between 0.0050-0.5250 and 0.0100-0.4100. The mean H was 0.7667. The accumulative DP was 0.9999999,. The accumulative EPP was 0.9999999. The scope of PIC was 0.6036- 0.8562 . PM was less than 10 -11 . The observed and expected genotype frequencies were evaluated using χ 2 test and all were in accordance with Hardy Weinberg equilibrium ( P > 0.05 ). Conclusion STR loci is an ideal genetic marker with powerful polymorphism and stable heredity. It can be used for individual identification and paternity in forensic medicine. The forensic DNA database model can be established successfully.

Carrier Detection and Presymptomatic Identification of Wilson Disease in Chinese by Non-Isotopic Linkage Analysis with Four Short Tandem Repeat Polymorphisms

Summary: Wilson disease (WD) is an autosomal recessive disorder of copper metabolism. To establish an efficient, accurate and fast diagnostic method for carrier detection and presymptomatic identification of WD in Chinese population, we studied haplotypes of short tandem repeat (STR) polymorphisms flanking the WD gene in 40 Chinese WD families. The results suggested that this genetic diagnosis system based on the four STR polymorphisms is of high value for the detection of potential carriers and WD homozygotes in families with at least one previously affected child. It is an efficient, accurate and fast diagnostic method that can be well suited for routine use in clinical laboratories.

CNV结合STR分型技术检测孕早期流产组织潜在葡萄胎效果及风险因素分析

目的:评估基因组拷贝数变异测序(CNV-seq)结合短串联重复序列(STR)多态性分析技术在检测孕早期(≤9周)流产物组织中潜在葡萄胎病例的应用效果.方法:收集2021年1月-2022年12月行孕早期流产组织CNV-seq结合STR多态性检测病例114例,其中部分新鲜绒毛组织进行CNV-seq结合STR多态性检测,部分组织行病理学检测.比较两种检测方法结果,并分析潜在葡萄胎病例的临床特征和影响因素.结果:CNV-seq结合STR多态性检测共检出染色体异常病例28例,阳性率为24.6%,其中单亲二倍体(UPD)8例,占阳性病例28.6%;病理学检出葡萄胎病例12例,阳性率为10.5%,其中完全性葡萄胎(CHM)10例,占阳性病例的83.3%.两种检测方法的结果一致率为89.5%,Kappa值为0.75,两种方法具较好一致性.潜在葡萄胎病例与非葡萄胎病例在年龄、孕次、流产次、β-hCG水平、超声表现等方面有差异,其中年龄、β-hCG水平和超声表现是潜在葡萄胎危险因素(均P<0.05).结论:CNV-seq结合STR多态性分析技术能有效检测孕早期流产物组织中潜在葡萄胎病例,有助于指导临床治疗和避免再次流产.

基于不同STR分型试剂盒的肿瘤组织身源鉴定方法

目的 建立基于常用STR分型试剂盒的肿瘤组织身源鉴定方法。方法 采用ForenSeq^(TM) DNA Signature Prep试剂盒检测55例配对肿瘤组织样本(肿瘤组织和同一个体正常组织成对)以及75例无关个体全血样本27个常染色体STR基因座的分型情况,并模拟55例肿瘤组织的全同胞、亲子对分型数据,统计成对肿瘤(paired carcinoma,PC)、肿瘤-无关个体(tumor-unrelated individual,UI)、肿瘤-全同胞(tumor-simulated full sibling,FS)与肿瘤-亲子(tumor-simulated parent-offspring,PO)的共有等位基因个数(number of total identical alleles,A_n)及状态一致性(identity by state,IBS)评分。以上述统计结果作为参照,建立8个常用STR分型试剂盒的肿瘤组织身源鉴定预测模型,并尝试构建一个专用于肿瘤组织身源鉴定的模型。使用另外23例配对肿瘤组织样本的检测结果对鉴定模型的准确性、灵敏度及特异度进行验证与评估。结果 (1)在任一试剂盒中,全不同基因座数量(A_0)在PC组与PO组之间差异无统计学意义。1个相同基因座数量(A_(1))、2个相同基因座数量(A_(2))和IBS评分在PC组与UI、FS、PO组之间差异均有统计学意义。(2)不同STR基因座的A_n与IBS评分在不同组别存在差异,其中,13个STR基因座(CSF1PO、D12S391、D19S433、D20S482、D2S1338、D3S1358、D4S2408、D7S820、D8S1179、FGA、TH01、TPOX、vWA)的A_(2)在PC组均高于其他STR基因座;2个STR基因座(D6S1043、PentaE)的A_(2)在UI组低于其他STR基因座。(3)成功构建了8个常用STR分型试剂盒的肿瘤组织身源鉴定预测模型以及15个STR基因座的肿瘤组织身源鉴定模型(15-STRs),灵敏度均达100%,特异度为97.56%~99.88%,准确度为97.59%~99.89%。其中,15-STRs模型的灵敏度为100%,特异度为99.88%,准确率为99.89%,高于常用商业化试剂盒。结论 本研究成功建立了8个常用STR分型试剂盒的肿瘤组织身源鉴定方法,拓展了肿瘤组织身源鉴定的应用范围。通过比较不同基因座在肿瘤组织身源鉴定中的差异,筛选出了15个特别适用于肿瘤组织身源鉴定的STR基因座,为未来肿瘤组织溯源的试剂盒构建提供了数据基础。

Application of Short Tandem Repeat in Prenatal Diagnosis for Phenmylketonuria during the First Trimester

Objective : To find a simple and rapid way far the prenatal diagnosis of phenyUce-tonuria (PKU) during the first trimester in order to prevent inborn PKU patients as early as possible. Methods :DNA was extracted respectively from the Mood sampleps of 9 families' members and chori-onic tissues of 9 embryoes by cliorionic vittus sampling (CVS). The independent short tandem repeat (STR) alleles of members in 9 families with classic form of PKU were analyzed and prenatal diagnosis were conducted using polymerase chain reaction (PCR) together with denaturing gradient gel elec-trophoresis(DGGE)and silver dyeing. Results-.We identified 1 embryo with PKU, 2 normal individuals and 5 carriers among 9 subjects. Conclusion: Prenatal diagnosis for PKU by STR is available in the first trimester. This procedure was promising and would be widely used in Chinese population.

常染色体STR三等位基因型在法医DNA分析中的研究进展

常染色体STR三等位基因型是法医DNA分析中常见的异常分型现象,给实际检案中证据权重的评估带来困难和不确定性。本文对法医DNA分析中常染色体STR三等位基因型的分类、形成机制、发生率、遗传模式、证据量化评估方法等进行综述,着重基于三等位基因型的不同类型阐述其形成机制及相应的遗传模式,并对三等位基因型的判定及其在亲子鉴定和个体识别中的证据量化评估策略进行讨论,为法医DNA分析中科学化、规范化地解析此类异常分型现象提供参考。

插入缺失位点和miniSTR在甲醛固定石蜡包埋组织中的应用检测

目的:研究插入缺失位点InDel与mini短串联重复序列(STR)遗传标记对甲醛固定石蜡包埋组织应用的价值。方法:19份甲醛固定石蜡包埋组织作为疑难检材,应用3种常染色体遗传标记多重扩增系统,即InDel系统(Investigatior■DIPplex Kit)、miniSTR系统(华夏白金扩增试剂盒)和STR系统(Goldeneye®20A),对STR分型不完整或失败的检材,再分别用InDel和miniSTR系统进行DNA分型检测,比较两者的分型质量和检出率。结果:19份甲醛固定石蜡包埋组织经Goldeneye 20A试剂盒检测,均分型不完整。应用miniSTR系统检测显示,7份样本的检出率100%,其中,D19S433基因座的检出率为100%,D5S818、D13S817和D1S1656基因座的检出率最小,为36.84%。应用InDel系统检测发现,1份样本InDel位点电泳分型完整,所有样本的位点丢失率均小于50%,其中7份样本的位点丢失率低至10%以下。结论:应用遗传标记对甲醛固定石蜡包埋组织这类疑难降解检材进行检测,插入缺失多态性位点InDel与miniSTR可以作为联合检测标记。

鼻咽癌组织STR基因座变异的研究

目的:探讨鼻咽癌组织21个常染色体STR基因座及Amel基因座等位基因的变异情况。方法:收集79例鼻咽癌患者的石蜡组织切片和外周静脉血,采用TIANamp FFPE DNA Kit试剂盒提取石蜡组织切片样本基因组DNA,Chelex-100提取血液样本基因组DNA。通过AGCU Expressmarker 22试剂盒进行PCR扩增,AB 3500 Genetic Analyzer检测STR型别。结果:79例鼻咽癌组织中,STR变异率为32.9%(26/79),变异类型包括Aadd、Anew、LOH、pLOH,发生率分别是6.3%、1.3%、6.3%、31.6%。在检测的STR基因座中有19个位点发生了变异,变异次数最多的基因座是D3S1358,D7S820、D19S433和Amel基因未发生变异。STR变异与鼻咽癌患者的性别、年龄、临床分期等均无明显相关性(P>0.05)。结论:鼻咽癌组织中STR基因座存在变异,但STR变异与患者性别、年龄、临床分期等无明显相关性。鼻咽癌组织中D3S1358基因座的变异率高,D7S820、D19S433和Amel基因座未发生变异。

组织芯片制备仪联合STR检测在葡萄胎病理诊断中的应用

目的探讨应用组织芯片制备仪精准分离绒毛组织和蜕膜组织联合短串联重复序列(STR)分析在葡萄胎病理诊断中的应用价值。方法收集中国医科大学附属盛京医院2017年3月至2022年9月可疑葡萄胎的组织标本90例。标本常规固定、脱水及石蜡包埋。分别应用组织芯片制备仪、传统方法分离标本中绒毛组织和蜕膜组织,应用检测试剂盒进行STR检测。结果应用组织芯片制备仪STR检测成功率为95.6%,采用传统方法STR检测成功率为60.0%。成功进行STR检测86例,包括葡萄胎67例和非葡萄胎19例。结论应用组织芯片制备仪精准分离绒毛组织联合STR分析技术提高了STR检测的成功率,在葡萄胎病理诊断中具有重要意义。

应用NGS确认STR检测中的OL峰案例研究

基于毛细管电泳平台的短串联重复序列(Short tandem repeats,STR)检测(Capillary electrophoresis-Polymerase chain reaction,CE-PCR)是现阶段法医DNA实验室的金标准,二代测序(Next-generation sequencing,NGS)在法医学上的应用已经初现端倪,通过NGS可以解决传统CE-STR对OL(Off-ladder)峰形成原因难以判定的问题.本文对在毛细管电泳(CE)平台的STR鉴定工作中发现的一种OL峰血样进行NGS研究,确定了此样品的OL峰为D18S51基因座稀有等位基因,该基因型因超出试剂盒Ladder范围而形成OL峰.研究结果表明,NGS对阐明OL峰形成原因具有独特的优势,相关技术将在今后法医物证鉴定中得到广泛推广和应用.

家系Y-STR基因座容差在系谱推断中的应用

目的研究中国汉族家系中Y-STR基因座容差规律,为SNP系谱推断与家系排查联用工作提供家系选择依据。方法选取3个遗传关系清晰的汉族家系,利用YFiler Platinum PCR扩增试剂盒,得到所采男性样本35个Y-STR基因座分型数据,统计分析Y-STR单倍型在世代遗传中的变化及1~7级亲缘关系中的容差。结果各家系突变基因座及突变次数有差异,Y-STR突变具有家系特异性,66.03%的突变发生在快、高速突变基因座。1~7级亲缘对在35个Y-STR基因座上容差在0~5个,最远6步长;在中、慢速突变基因座上容差在0~2个,最远3步长;在快、高速突变基因座上容差在0~3个,最远6步长。结论联合应用SNP系谱推断技术与Y-STR家系排查,0容差及多容差均需考虑。可优先筛查在全部35个Y-STR基因座上0~3个容差且在中、慢速基因座上0~1个容差的家系。差异数符合条件时,步长较远的家系应谨慎排除。同时,应谨慎增加快速突变基因座。