单亲案亲权鉴定结果判定策略

目的探讨用STR基因座进行单亲鉴定出现矛盾基因座时下结论的策略。方法根据基因频率和遗传规律,推导单亲案亲权鉴定时的非父排除率。根据平均单亲非父排除率和平均突变率,用二项分布公式分别计算出现不同数目矛盾基因座时真父和假父的概率和似然率(亲权指数)。结果对STR共显性基因座,其单亲非父排除率的计算公式为:PEM=∑i=n1pi2(1-pi)2 ∑i相似文献   

单亲案的亲权概率的计算及认定标准

确定单亲案的亲权概率计算方法和认定标准。用多基因座DNA分析方法和计算多基因座累积平均非父排除率计算公式。检测8个以上的DNA多态性基因座,在等位基因的遗传不违反孟德尔规律的前提下,父权概率都可达到或超过0.9990的标准;对不存在亲生关系的案例,在用本方法时,都有3个或更多的基因座的等位基因遗传违反孟德尔规律。对单亲案的亲权鉴定,检测的多态性基因座要在8个以上。在肯定亲生关系时,父权概率要达到或超过0.9990;在否定亲生关系时,必须有3个以上或更多的基因座违反孟德尔遗传规律。     

Identifiler^TM系统在亲子鉴定中的应用评估

目的评估Identifiler^TM系统15个短串联重复序列（STR）基因座在亲子鉴定中的检验能力。方法用Identifiler^TM系统检测3277例亲子鉴定案例,观测和分析该系统在亲子鉴定中的排除能力及基因突变率。结果累积非父排除率为0．999998827,累积个体识别能力为0．99999999999999998。3277例亲子鉴定中有2863例认定亲权关系,347例排除亲权关系;观察到65例中有1个STR基因座发生突变,2例中有2个STR基因座发生突变。结论Identifiler^TM体系应用于亲子鉴定是高效、可靠的。     

二联体亲权鉴定风险分析

目的探讨二联体亲权鉴定时存在的风险。方法选取22组经Goldeneye~(TM) 20A试剂盒检测后只有一个或没有不符合基因座的无关个体对构建假想家系。对其增加检测STRtyper-10G和/或AGCU 21+1 STR系统直至所有组不符合基因座个数大于3个,累积父权指数(CPI)不大于0.000 1。以三种规则:(1)不符合基因座数大于3个;(2)CPI值小于0.000 1;(3)同时满足(1)和(2),作为排除依据,使用不同数量的基因座(19个、26个、39个和46个)进行检测,讨论无关个体对的排除情况是否存在差异。结果 22组无关个体对,使用19个基因座和39个基因座以上的检测系统达到排除结果的分别为0组和22组。结论二联体亲子鉴定,使用19个基因座进行检测仍存在结果错判,39个基因座以上的检测系统能更有效的避免二联体的鉴定风险。     

云南汉族家系Y—STR基因座突变率研究

目的研究Y—filer试剂盒中DYS19等基因座在云南省汉族家系样本中的突变率。方法应用Y—filer试剂盒中的DYS456等16个Y—STR基因座对云南省30个汉族家系爷／孙、叔／侄和兄弟／堂兄弟亲权关系的106份样本进行基因分型检测,对DYS19等基因座分型与家系其他成员不同的样本分别进行了单位点的测序。结果6个（周姓、徐姓、王姓、袁姓、许姓、李姓）不同父系姓氏7例样本的10个Y—STR基因座发生突变,分别是DYS19、DYS385各2例,DYS389Ⅰ、DYS389Ⅱ、DYS390、DYS458、DYS393、DYS635各1例,总突变率为5．549‰;王姓、袁姓、许姓家系中各有1例样本分别在2个Y—STR基因座上发生了突变。结论男性家系中随机样本Y—STR基因座的突变率高于父子对样本;用Y—STR基因座进行父系亲权鉴定和男性嫌疑人的家系排查时,既使有2个Y—STR基因座分型不同时也不要轻易排除其来源于同一父系家系。     

227例疑似常染色体STR基因座突变的回顾分析

目的对疑似常染色体STR基因座突变案例进行研究分析。方法从本鉴定中心亲子鉴定案例中整理出疑似突变案例227例进行分析,筛选等位基因突变案例,统计各STR基因座的突变数,计算疑似突变案例的CPI值,分析突变的规律及其特点。结果 227例疑似突变案例中有3个案例为排除亲权关系,其余案例共在18个STR基因座位上出现228次突变,每个突变案例的突变基因座数目为1～2个,最多突变步数为四步。3例排除亲权关系案例计算扩增20A试剂盒后的CPI值都104,标准三联体联合使用20A和10G试剂盒时CPI值全部超过了104,二联体单亲鉴定联合使用20A和10G试剂盒时有99.45%的CPI值超过104。结论 STR基因座等位基因突变现象较为常见,当出现疑似突变案例时应增加STR基因座的检测数量,或补充样本为完整三联体,以最大程度地降低误判风险。     

39个STR基因座在二联体亲子鉴定突变案例中的应用

目的探讨39个常染色体STR基因座在二联体亲子鉴定突变案例中的应用价值。方法提取全血基因组,采用AGCU Expressmarker 22荧光检测试剂盒进行二联体亲子鉴定,若出现1~2个矛盾基因座,则加做AGCU 21+1 STR荧光检测试剂盒,计算累计父权指数(CPI)值,根据亲子鉴定判断标准判定结果。结果共检测502例二联体亲子鉴定案例,其中排除亲权关系17例,485例不排除亲权关系,10例出现单基因座不符合。加做AGCU 21+1后除1例出现一个新的STR基因座不符合,其他均符合遗传规律,且CPI≥10 000。结论 39个STR基因座的联合应用能够有效解决二联体亲子鉴定中的大部分突变案例。     

6个五核苷酸STR基因座荧光复合扩增体系的建立

目的 构建6个五核苷酸STR基因座荧光复合扩增体系。方法筛选6个多态性程度较高的五核苷酸STR基因座D10S2325、Penta B、Penta W、PentaX、Penta D和PentaE,按照复合扩增引物设计要求,重新设计引物并标记荧光染料,经反复调整和优化,构建6基因座荧光复合扩增体系,并用该复合扩增体系对239名武汉汉族无关个体进行分型。结果6个五核苷酸STR基因座荧光复合扩增体系分型稳定,可重复性好,与各自相应单基因座分型结果完全一致;累积个人识别率达0．999999988,累积非父排除率达0．998063807。结论本文构建的6个五核苷酸STR基因座荧光复合扩增体系具有很高的法医学实用价值,可作为商品化试剂盒的有效补充。     

台湾汉族群体15个STR基因座的遗传多态性

目的为获得15个基因座在台湾汉族群体中的遗传学数据,探究其在法医学检验中的应用价值. 方法用ProwerPlex(r)16 System荧光标记试剂盒 (Promega公司)检测15个STR基因座的多态性. 结果在189例台湾汉族随机个体中,15个STR基因座分别检出6、7、15、15、19、10、8、8、7、8、10、8、9、6、19 个等位基因,各等位基因频率为0.002 6～0.452 4.观察杂合度(HO)为 0.608 2～0.926 1 ,期望杂合度(HE)为0.6103～0.916 2, 多态信息含量(PIC)为0.5491～0.9073,亲权排除率(PE)为0.353 2～0.826 4,个体识别率为0.609 1～0.914 3.累积亲权排除率(PE)为 0.999 999, 累积个体识别率为0.999 999 999. 结论该15个STR基因座具有很高的多态性,已可以满足大多数的亲权鉴定和法医学个人识别的需要.     

北京地区汉族人群Penta B、E、C基因座遗传多态性

微卫星(STR)基因座常根据串联重复单元的核苷酸数进行分类。其中五核苷酸重复序列(Pentanucleotide)是指串联重复单元为五核苷酸的STR基因座,其结构比四核苷酸重复序列更加稳定[1]。四核苷酸序列基因座是法医DNA分析最常用的基因座,而五核苷酸序列基因座在当前法医学所采用的商品化的试剂盒中仅有Penta E、Penta D(Promega,USA),所以存在很大的研究空间。本文选取Penta B、Penta E和Penta C(基因座信息见表1)三个STR基因座,在北京地区汉族人群中,随机抽取203名无关个体进行多态性调查。表1 Penta B、E、C基因座信息基因座基因…     

单亲亲子鉴定的分析研究

目的从理论和实际应用方面客观评价13～15个STR位点应用于单亲亲子鉴定的准确性。方法依据中国人群基因频率资料,计算单亲亲子鉴定的非父排除率及单亲亲子鉴定的亲子关系概率,并选择有明确排除结论的104例排除案例,分析统计其中父-子二联体出现的排除指标数。结果对于单亲亲子鉴定,选用13～15个STR位点,联合非父排除率为0.9805～0.9906;亲子关系概率均大于99.73%。104例二联体排除案例中,有3例的排除指标数小于2,未发现排除指标为零的现象。结论若应用ProfilerPlus和CofilerPlus试剂盒的13个STR位点进行日常单亲亲子鉴定工作,存在微弱漏判非父的风险,必要时增加检测指标数。不排除案例的单亲亲子鉴定,其亲子概率均可达国际认定标准。     

VNTR D17530位点多态性在亲子鉴定中的应用

运用微量热启动PCR技术,对20例正常家系的遗传学分析,证实D17530位点的遗传符合孟德尔遗传规律,表现为简单的共显性遗传。同时,对100例亲子鉴定案例进行回顾性分析研究,证明D17S30位．在多态性可应用于我国法医学亲子鉴定。根据D17S30位点基因频率估算的排除概率（74．04％）与其实际排除能力（80．00％）无显著差异。在15倒排除亲子关系的案例中,有2例由D17S30位点单独取得排除证据。D17S30位点是法医学上有重要意义的遗传学标记,可用于亲子鉴定。     

Allele frequency distribution based on 17 STR markers in three major Dravidian linguistic populations of Andhra Pradesh, India

Allele frequencies for 15 tetranucleotides and 2 pentanucleotides repeat loci were determined in 317 unrelated, healthy individuals of Andhra Pradesh, India, belonging to three pre-dominant endogamous populations namely, Kappu Naidu, Kamma Chaudhary and Kapu Reddy. Adherence to the expectations of the Hardy-Weinberg equilibrium (HWE) was confirmed for all loci with few exceptions, which were not significant after applying Bonferroni's correction. Statistical parameters of forensic interest; observed heterozygosity, probability of homozygosity, probability of extact test, power of discrimination, match probability, polymorphism information content, power of exclusion and mean paternity index were determined for all loci. The present study reveals that Penta E and D2S1338 are the most informative loci in all the studied populations. The combined power of discrimination was greater than 0.976, whereas the cumulative power of exclusion gave an expected value of 0.9999 for all the tested microsatellite loci. No difference was observed in the discriminatory power of 15 loci in studied populations on comparison with other populations of India. Population differentiation tests revealed significant differences between the studied and neighboring populations at several loci. Analyzed parameters indicate the utility and efficacy of the studied 17 STR systems as a powerful tool in forensic human identification, paternity testing and human population genetic studies.     

Identifiler体系在单亲血缘关系鉴定中应用价值的研究

目的　研究 16基因位点Identifiler体系在单亲血缘关系法医鉴定中的应用价值。　方法　对无关个体中随机抽样组成的假设父—子二联体 10 0例、正常人群中已知真父—子二联体 10 0例及已知非父—子二联体 10 0例、实际单亲血缘关系亲子鉴定案 2 2 8例、特意省去母亲的二联体鉴定案 136例 ,应用Identifiler体系的 16基因位点进行检测 ,得出每案例的RCP值 ,将检测结果同应用其他体系检测的结果比对 ,同三联体检测结果比对 ,同真实情况比对 ,计算出单独使用Identifiler体系在单亲血缘关系法医鉴定中的正确率。　结果　对 2 2 8例单亲鉴定案应用Identifiler体系检测的结果 ,同应用ProfilerPlus和Cofiler两个体系再加用 2 4个其他位点银染检测 (共 37个位点 )的结果完全相同 ;对无关个体 10 0例及真父—子二联体 10 0例及非父—子二联体 10 0例 ,用Identifiler体系检测的结果同调查核实的真实情况完全相符 ;对 136例特意省去母亲的二联体案 ,用Identifiler体系检测的结果同原实际检案中三联体检测的结果完全相同。　结论　单独使用Identifiler体系完全可以解决法医亲子鉴定中的单亲血缘关系鉴定问题。     

Allele frequencies for STR loci of the Powerplex 16 multiplex system in five endogamous populations of India

Allele frequencies for the 15 STR locus of PowerPlex 16 were analyzed in 95 healthy unrelated individuals belonging to five important population groups inhabiting different part of India. Fifteen loci studied are Penta E, D18S51, D21S11, THO1,D3S1358, FGA, TPOX, D8S1179, vWA, Amelogenin, Penta D, CSF1PO, D16S539, D7S820, D13S317 and D5S818. In addition of all tetra nucleotide loci, two penta nucleotide loci Penta D and Penta E of the studied system are also found highly polymorphic in all the five studied populations of India. These loci are found highly informative in solving paternity cases and other forensic testing in studied population.     

Probability of exclusion in paternity testing: time to reassess

The average exclusion probability is a measure of efficiency in paternity testing; it refers to the a priori ability of a battery of tests to detect paternity inconsistencies. This parameter measures the capacity of the system to detect a false accusation of paternity. Traditionally, this average exclusion probability has been estimated as the probability of excluding a man who is not the father by an inconsistency in at least one of the studied loci. We suggest that this criterion should be corrected, as currently the presumed father is excluded when at least three genetic inconsistencies are found with the child being tested, not just one. This change of criterion has occurred because of the use of microsatellite loci, whose mutation rates are much greater than those of the coding genes used previously in paternity studies. We propose the use of the average probability of exclusion for at least three loci (not only one), as an honest measure of the combined probability of exclusion of several loci, and we propose an algebraic expression to calculate it.     

Laboratory evidence of unsuspected parental consanguinity among cases of disputed paternity

A search was conducted to find evidence of possible incestuous unions between the biologic parents of children involved in 2500 paternity cases. Suspicion was raised when either (1) a mother and her child possessed identical HLA phenotypes, or (2) the child appeared to be possibly homozygous for one maternal haplotype (i.e., one of the child's HLA haplotypes was a blank). These mother-child HLA-haplotype dualisms (MHDs) occurred in 5% of all cases. Frequency of exclusion of the accused men in cases demonstrating MHD, was compared with the remaining paternity cases.No significant difference was found in overall exclusion rates between MHD cases and controls when exclusion produced by HLA and red cell antigen systems were observed. However, there was a greater rate of exclusion in MHD cases when comparing exclusions produced by red cell antigen systems regardless of whether HLA tests excluded paternity (p < 0.025). MHD cases involving teenaged mothers differed from control cases in frequency of exclusion of paternity only on the basis of red cell antigen phenotyping (p < 0.005).The HLA system's usefulness in paternity testing is diminished when there is MHD; multiple, independently-inherited systems are relatively more useful in these circumstances.The search method detects only half of potential incest cases; proof of incest requires more extensive testing for homozygosity among other polymorphisms. Since calculations of likelihood of paternity are inappropriate in cases involving close consanguinity, detection and follow up studies are important.Data suggest that one-fifth of MHD cases may involve first degree consanguinity and that the incest rate among paternity cases may be as high as 2%.     

STR等位基因频率对父权指数的影响

目的观察中国汉族不同人群STR等位基因频率对联合父权指数(CPI)的影响。方法随机取108例13个CODIS基因座分型结果不排除父权关系的三联体案和二联体案,用5个不同地区人群的等位基因频率计算CPI值。结果三联体案的CPI值在2077.63～50897711626.46之间,同一案例的最大CPI与最小值CPI之比大于100者有20例(19.52%);二联体案的CPI值在25.12～2998685141之间,同一案例的最大CPI与最小值CPI之比大于100者有13例(12.04%)。结论不同人群等位基因频率计算CODIS基因座所得的CPI值在部分亲权鉴定案中有很大的差异。为了防止等位基因频率不确定性带来的误差,建议在亲权鉴定中用保守法计算CPI值。