一种新的基于STR的染色体三体性疾病诊断策略中遗传标记的评估

背景:在此前发表的文章中,我们提出了一种新的基于短串联重复序列(Short Tandem Repeats,STR)的染色体三体性疾病的诊断策略.当应用这种策略来检测特定染色体拷贝数时,需要从人类基因组众多的STR中选择适宜的染色体特异性STR基因座构建一个诊断系统,根据系统中的STR基因座是否检测到三种不同的等位基因产物来判断个体是否为三体患者.目的:本研究拟进一步提出并验证对单个STR基因座及由多个STR基因座构成的诊断系统的评估方法,旨在帮助选择适宜的STR基因座构建一个高效能的诊断系统.方法:我们提出一个新的参数--三等位基因栓出率,并推导出该参数的计算公式,用于定量评估一个STR基因座在这种诊断策略中的效能.在此基础上,推导出另一个数学公式,计算一个非整倍体诊断系统能够在一个三体性患者?哌 检测到三个不同等位基因的概率,根据这个概率的大小来衡量系统诊断效能的高低.最后,我们将所提出的两个公式用于评估我们在先前研究中构建的一个21三体的诊断系统.结果:这个21三体诊断系统由9个21号染色体特异性STR基因座构成.根据我们所提出的两个公式,这些STR基因座的三等位基因检出率在0.203-0.638之间,该系统在21三体患者能够检测到三个不同等位基因的概率大于0.95.结论:我们所提出并验证的公式可以对单个STR基因座和系统的诊断效能进行定量评估,帮助选择适宜的STR遗传标记,并确定一个高效能诊断系统所需的STR基因座的数量,从而为这种诊断策略的广泛应用提供基础.     

9号染色体短臂上7个STR基因座在基因扫描中的信息表现

为了初步探讨7个位于染色体9p区域的短串联重复序列(shorttandemrepeat,STR)基因座:D9S288、D9S157、D9S1748、D9S171、D9S161、D9S1817和D9S1805在遗传学研究及法医学应用中的意义,随机抽取225名湖南汉族无关个体,复合PCR技术扩增上述基因座,ABI377全自动测序仪进行基因分型,共检出75种等位基因,通过对基因型及等位片断频率分布的研究和数据统计分析,7个基因座基因频率分布在0.002～0.800之间,构成243种基因型。7个STR基因座基因型分布均符合Hardy Weinberg平衡定律(P>0.05),杂合度(heterozygosity,H)介于0 347～0.844之间,个体识别力(discriminationpower,DP)为0.346～0.841,非父排除率(probabilitiesofpaternityexclusion,PPE)为0.308～0.738,多态信息含量(polymorphicinformationcontent,PIC)在0.328～0.822之间。种族比较结果显示,湖南汉族与非洲黑人及欧洲白人在大多数基因座均存在显著差异(P<0.001)。研究结果丰富了中华民族基因数据库,在人类群体遗传学及法医学研究领域有重要应用价值。     

用多重PCR检测上海地区汉族人群9个STR基因座的多态性

利用多重PCR和四色荧光（5－FAM,JOE,NED和ROX）自动化检测技术调查上海地区汉族人群D3S1358、vWA、FGA、D8S1179、D21S11、D18S51、D5S818、D13S317、D7S820等9个STR基因座多态性分布并计算 该9个基因座的的基因频率（Pi)、个体鉴别力（DP）、无偏倚期望杂合性（H）、多态性信息含量（PIC）和非父排除概率（PE）。结果显示：9个STR基因座的基因型分布符合Hardy-Weinberg平衡,9个STR基因座中FGA基因座的DP值最高为0.9584,D8S1179的H值最高为0.9403,D18S51的PIC值最高为0.8560,D18S51的PE值最高为0.7391,9个STR基因座累积个体鉴别力（CDP)为0.9999996,累积非父排除能力（CPE）为0.99991。9个STR基因座适合作为中国人群的遗传标志,用于人类学、遗传疾病基因连锁分析、法医学亲子鉴定和个体识别等研究领域。     

STR基因座中检测出三带型等位基因2例

针对出现的三等位基因2例亲子鉴定案件,同时检测其唾液斑及毛发,应用Goldeneye 20A、PowerPlex 6C、Investigator 24plex QS及华夏白金试剂盒进行检测验证。结果显示在2例二联体亲子鉴定案件中,一例母亲的D18S51基因座分型为13/16,孩子的分型为15/16/17;另一例父亲的D7S820基因座分型为8/11/12,孩子的分型为10/11。唾液斑及毛发样本结果与FTA血卡结果一致,应用Goldeneye20A、PowerPlex 6C系统、Investigator 24plex QS及华夏白金试剂盒验证检测的结果相同。在日常亲子鉴定案件中,出现三带型现象较为罕见,针对这种现象,需进行认真判读及确认,以保证检测结果的准确性。     

不同亲子鉴定试剂盒对D7S820基因座稀有等位基因检测结果比较

目的：观察分析用不同亲子鉴定试剂盒对D7S820基因座稀有等位基因检测结果的差异。方法：280名不同个体的血样DNA提取和基因型检测,按中华人民共和国公共安全行业标准GA／T382—2002和GA／T383—2002进行;分别用Identifiler试剂盒（美国AB公司）、PowerPlex 18Dsystem试剂盒（美国普洛麦格公司）、GoldeneyeTM20A试剂盒（北京基点认知技术有限公司）,经PCR复合扩增STR基因座,用AB公司DNA序列分析仪电泳分离扩增产物和激光扫描分析。结果：检测到280名不同个体的常用常染色体STR基因座的等位基因。,其中六份样本在D7S820基因座上,Identifiler试剂盒检测的基因型与PowerPlex 18D—system和GoldeneyeTM20A试剂盒检测的基因型结果有差异。结论：不同厂家生产的试剂盒检测常用常染色体D7S820基因座的稀有等位基因存在有一定误差。     

306例亲子鉴定案件基因突变的观察与分析

STR基因座突变是亲子鉴定中较为常见的现象,本研究采用Golden-20A试剂盒对306例结论为"肯定"的亲子鉴定案例进行基因分型检测,观察和分析亲子鉴定案件中20个短串联重复序列(STR)基因座的突变现象,对不满足遗传规律的案件,分析其基因座及等位基因的相应特征。结果表明在306例亲子鉴定案例中,共观察到8例基因突变,其中一步突变为7例,二步突变为1例,涉及6个STR基因座。8例突变中,父系来源突变和母系来源突变的比例为3:1。通过本研究可知STR基因座突变的特点,司法鉴定中应不断积累突变数据,谨慎做出判断,以保证鉴定结果的准确性。     

中国东北汉族群体3个MiniSTR基因座的遗传多态性研究

我们使用D10S1248、D14S1434和D22S1045三个miniSTR基因座对东北汉族群体的141名随机个体样本进行遗传多态性研究, 通过荧光标记多重PCR扩增, 310遗传分析仪电泳, 确定个体的基因型, 获得相应的群体遗传数据。对所得数据进行统计学分析。共检出25个等位基因, 56种基因型。3个基因座在所检测群体内均符合哈迪温伯格平衡, 具有较高的杂合度、个体识别率和非父排除率。累积个体识别率为0.99876, 累计非父排除率为0.89819。3个基因座在东北汉族均具有高度的遗传多态性,在群体遗传学和法医学研究中有一定的应用价值。     

福建畲族群体17个Y-STR基因座单倍型及遗传关系

应用Y-filerTM试剂盒及基因分型技术,检测152份福建畲族无关男性个体17个Y-STR基因座的多态性分布,计算等位基因频率及单倍型多样性,并结合已公开发表的其他11个群体相应基因座的单倍型资料,分析福建畲族群体遗传距离和聚类关系。福建畲族DYS385a/b基因座检出50种单倍型,其余15个Y-STR基因座分别检出3-11个等位基因,基因多样性GD值在0.4037(DYS391)～0.9725(DYS385a/b);观察到DYS19和DYS390基因座双等位基因和DYS385a/b基因座三等位基因,以及DYS448等部分基因座出现的"off-ladder"等位基因现象。17个Y-STR基因座共同构成的单倍型144种,其中138种单倍型出现1次,5种出现2次,1种出现4次,累计GD值为0.9990。从遗传距离分析发现,福建畲族与浙江汉族之间的遗传距离最近(0.0042),与青海藏族(0.2378)之间的遗传距离相对较远。福建畲族最靠近由台湾群体、浙江汉族、南方汉族等典型南方汉族群体聚成的分支区域。结果表明该17个Y-STR基因座在福建畲族群体中具有丰富的遗传多态性,对建立Y染色体STR数据库,研究群体遗传学和进行法医学应用有重要意义。     

GoldenEye 16BT体系在ABO基因及亲子鉴定中的应用评估

目的:调查湖南地区汉族ABO血型及其基因型,评估GoldenEye 16BT体系在血型与亲子鉴定中的检验能力.方法:以533例亲子鉴定案例为基础,用抗A(B)血清检测1248个个体的血清学血型,观察和分析GoldenEye 16BT体系在ABO基因型检测和15个STR基因座的遗传学数据资料.结果:(1)1248个个体中,1245(97.76%)个个体的血清学血型与基因型检测结果相符,有3例O型血经基因检测发现1例含A基因、2例含B基因 .688名无关个体血清学血型A＞O＞B＞AB,等位基因频率O＞A＞B.(2)GoldenEye 16BT体系累计个体识别能力为0.9999999999999999971,累积非父排除率为0.999999999999971.533例亲子鉴定中有380例肯定亲权关系,153例排除亲权关系;11例中有1个STR基因座发生突变.结论:GoldenEye 16BT体系用于ABO基因型检测与亲权鉴定是高效、可靠的.     

湖南地区1013例亲子鉴定中的STR突变位点研究

对亲子鉴定常用的ABI公司Indentifiler荧光标记复合扩增试剂盒中的15个短串联重复序列及D14S306、D16S3391、D5S2500、D12S391、D13S796、D1S518位点的突变现象进行研究.在1013例认定亲子关系案例中,对发现有一个基因位点发生突变的案例增加8个常染色体STR（short tandem repeat）基因座检测,使其父权相对机会（RCP）大于99.999%以上,并对突变位点进行测序.在1013例认定亲子关系案例中,发现11例有一个基因位点发生突变,8次突变事件为父源性突变,突变位点包括vWA、FGA、D14S306、D13S317、D21S11、CSFIPO、D16S3391;其余3例突变来源不明,包括FGA、D13S796、D3S1358.以vWA和FGA的突变率最高,为0.15%,平均突变率为（0.09&#177;0.370&#215;10^-3）%.本鉴定所常用的21个基因座,突变率低,具有较高的推广价值.     

Parentage testing of racing camels (Camelus dromedarius) using microsatellite DNA typing

The camel racing industry would have added value in being able to assign parentage with high certainty. This study was aimed at assessing and applying microsatellite multiplexes to construct a parentage testing system for camels. An efficient system of 17 loci from 700 camel samples was used to construct a database of unrelated adults. Based on this, we estimated measures of polymorphism among the markers. In three multiplex reactions, we detected a total of 224 alleles, with 5–23 alleles/locus (mean = 13.18 ± 6.95 SD) and an average heterozygosity (H_E) of 0.54 (range 0.032–0.905). The total parentage exclusion probability was 0.99999 for excluding a candidate parent from parentage of an arbitrary offspring, given only the genotype of the offspring, and 0.9999 for excluding a candidate parent from parentage of an arbitrary offspring, given the genotype of the offspring and the other parent. We used 15 juveniles for parentage testing, as well as 17 sires (bull camels) and 21 dams (cows). In the case of parentage assignment, the microsatellite panel assigned all 15 offspring parentage with high confidence. Overall, these findings offer a set of microsatellite markers that are easy, simple and highly informative for parentage testing in camels.     

A partial trisomy 15q due to 15;17 translocation detected by conventional cytogenetic and FISH techniques

We report a case having multiple abnormalities including the simultaneous presence of the heart defect and central nerve system abnormalities, which has been reported in a few cases, and with a partial trisomy 15q. Partial trisomy 15q has been inherited from a balanced translocation carried by his phenotypically normal father, detected by traditional banding and fluorescence in situ hybridization (FISH). Application of FISH using whole chromosome specific library probes, locus specific and repetitive probes allowed us to detect the translocation between chromosomes 15q and 17q. Simultaneous application of probes revealed the position of the translocation. Interestingly, in addition to the chromosomes 15 pericentromeric signals, the use of chromosome 15 beta-satellite III probe demonstrated an extra signal on chromosome 14 in both metaphase, and lighted three signals interphase nuclei which was inherited from his father. This patient is compared with other partial trisomy 15q patients reported in the literature. The results are also discussed in relation to genetic counselling for the possible relation of chromosome abnormality and clinical findings.     

Deletion mapping of DNA markers to a region of chromosome 5 that cosegregates with schizophrenia

Two independent lines of evidence support the localization of a schizophrenia susceptibility locus to the proximal long arm of chromosome 5. A partial trisomy of chromosome 5 (5q11.2-q13.3) cosegregates with the disorder in a Canadian family of Chinese descent, and DNA markers from proximal 5q cosegregate with schizophrenia (plus related disorders) in families of British and Icelandic descent. We constructed a human:hamster hybrid cell line (HHW 1064) whose only human complement is a chromosome 5 that is missing the trisomic region associated with schizophrenia. In combination with a "matched" cell hybrid (HHW 105) containing an intact chromosome 5, we physically mapped DNA markers relative to the trisomy. "Schizophrenia-linked" DNA markers p105-153Ra (D5S39) and p105-599Ha (D5S76) map within the trisomy and proximal to the 5q11.2 breakpoint, respectively. The hybrid cell lines HHW 105 and HHW 1064 together provide a means to identify and generate syntenic DNA markers to further investigate the location of a schizophrenia locus.     

Development and characterization of 11 microsatellite markers in the rock sparrow,Petronia petronia

Eleven polymorphic microsatellite loci were isolated in the passeriform Petronia petronia using the enrichment protocol FIASCO (fast isolation by AFLP of sequences containing repeats). We detected three to 13 alleles per locus in 25 specimens collected from an Italian population. The level of expected heterozygosity ranged from 0.439 to 0.856. One locus is sex linked to the Z chromosome. The total exclusionary probabilities using these loci for the first and the second parent were 0.978 and 0.999, respectively. These are the first microsatellite loci characterized from the rock sparrow that can be used for estimating population structure and for large‐scale parentage analysis.     

Analysis of microsatellites and parentage testing in saltwater crocodiles

Fifteen microsatellite loci were evaluated in farmed saltwater crocodiles for use in parentage testing. One marker (C391) could not be amplied. For the remaining 14, the number of alleles per locus ranged from two to 16, and the observed heterozygosities ranged from 0.219 to 0.875. The cumulative exclusion probability for all 14 loci was .9988. the 11 loci that showed the greatest level of polymorphism were used for parentage testing, with an exclusion probability of .9980. With these 11 markers on 107 juveniles from 16 known breeding pairs, a 5.6% pedigree error rate was detected. This level of pedigree error, if consistent, could have an impact on the accuracy of gentic parameter and breeding value estimation. The usefulness of these markers was also evaluated for assigning parentage in situations where maternity, paternity, or both may not be known. In these situations, a 2% error in parentage assignment was predicted. It is therefore recommended that more micro-satellite markers be used in these situations. The use of these microsatellite markers will broaden the scope of a breeding program, allowing progeny to be tested from adults maintained in large breeding lagoons for selection as future breeding animals.     

Trisomy 20p: case report and genetic review

Partial trisomy for the distal part of the short arm of chromosome 20 reported in a girl aged 11/2 years with typical craniofacial dysmorphies and psychomotor retardation. The trisomy resulted from a paternal translocation t(14;20) (q32.3;p11.1). The review of 25 cases of partial trisomy 20p showed that most cases (22 : 25) were due to parental translocations. Predominant involvement of small chromosomes in translocations with chromosome 20 was also detected.     

Uniparentale Disomien und Mosaike

Of the various mechanisms of formation of uniparental disomy (UPD) discussed in the literature, the mechanism of trisomy rescue is mostly prone to mosaicism from a trisomy cell line and from a disomy 46, XN uniparental cell line. Therefore, low level or undetected mosaicism has been assumed for a significant number of UPD cases. The clinical consequences of trisomy/UPD mosaicism probably depend on the chromosome involved and the proportional content in individual tissues. As the trisomy cell line of some mosaics might have a disadvantage in biological selection it might not be detected in routine lymphocyte investigations. For evaluation of the clinical relevance in the case of an imprinted chromosome the associated imprinting disorder must also be considered. In a postnatal setting analysis of UPD is indicated in the case of clinical, cytogenetic and molecular data. In the prenatal setting genetic counseling of the parents should be offered prior to any laboratory testing. In total, the impact of mosaicism associated with UPD has to consider the affected chromosome, the associated phenotype, the mechanism of formation and the laboratory method used.     

Parentage testing in alpacas (Vicugna pacos) using semi-automated fluorescent multiplex PCRs with 10 microsatellite markers

The aim of this study was to assess and apply a microsatellite multiplex system for parentage determination in alpacas. An approach for parentage testing based on 10 microsatellites was evaluated in a population of 329 unrelated alpacas from different geographical zones in Perú. All microsatellite markers, which amplified in two multiplex reactions, were highly polymorphic with a mean of 14.5 alleles per locus (six to 28 alleles per locus) and an average expected heterozygosity ( H _E) of 0.8185 (range of 0.698–0.946). The total parentage exclusion probability was 0.999456 for excluding a candidate parent from parentage of an arbitrary offspring, given only the genotype of the offspring, and 0.999991 for excluding a candidate parent from parentage of an arbitrary offspring, given the genotype of the offspring and the other parent. In a case test of parentage assignment, the microsatellite panel assigned 38 (from 45 cases) offspring parentage to 10 sires with LOD scores ranging from 2.19 × 10⁺¹³ to 1.34 × 10⁺¹⁵ and Δ values ranging from 2.80 × 10⁺¹² to 1.34 × 10⁺¹⁵ with an estimated pedigree error rate of 15.5%. The performance of this multiplex panel of markers suggests that it will be useful in parentage testing of alpacas.     

Severe psychomotor retardation in a boy with a supernumerary derivative chromosome resulting in partial trisomy 21 and partial trisomy 7p

We report on a 12-year-old boy with a supernumerary chromosome der(21)t(7; 21)(p21; q21.3)mat, resulting in a partial trisomy 21 and a partial trisomy 7p. The patient has a severe psychomotor retardation. Although he has most of chromosome 21 in three copies, he does not have a phenotype of Down syndrome (DS). In addition to cytogenetic analysis, molecular analysis confirmed that the "DS critical region" on chromosome 21 (21q22) is not present in three copies, since the breakpoint of the partial trisomy 21 was found to be located distal to the marker locus D21S145 but proximal to D21S226. The patient's severe mental retardation is probably due to the small telomeric 7p trisomy, having the breakpoint between markers D7S507 and D7S488. In comparison with previously published cases of partial trisomy 7p, the phenotype of this patient indicates that there is a region around the distal part of band 7p21 that in three copies might contribute to many of the facial features common to patients with partial trisomy 7p.