Characterization of 26 miniSTR loci for improved analysis of degraded DNA samples

An additional 20 novel mini-short tandem repeat (miniSTR) loci have been developed and characterized beyond the six previously developed by our laboratory for a total of 26 non-CODIS miniSTR markers. These new markers produce short PCR products in the target range of 50-150 base pairs (bp) by moving the primer sequences as close as possible-often directly next to the identified repeat region. These candidate loci were initially screened based on their small amplicon sizes and locations on chromosomes currently unoccupied by the 13 CODIS STR loci or at least 50 Mb away from them on the same chromosome. They were sequenced and evaluated across more than 600 samples, and their population statistics were determined. The heterozygosities of the new loci were compared with those of the 13 CODIS loci and all were found to be comparable. Only five of the new loci had lower values than the CODIS loci; however, all of these were much smaller in size. This data suggests that these 26 miniSTR loci will serve as useful complements to the CODIS loci to aid in the forensic analysis of degraded DNA, as well as missing persons work and parentage testing with limited next-of-kin reference samples.     

Validation and casework application of a Y chromosome specific STR multiplex

A series of validation experiments was performed for a Y chromosome specific STR multiplex system following the suggestions made by the Technical Working Group DNA Analysis Methods (TWGDAM). The multiplex PCR products were detected on Perkin-Elmer 373 and 377 automated sequencers using two labeling colors. No problems regarding the stability, robustness and sensitivity of the Y STR multiplex were observed. Mixture studies revealed a cut off rate similar to autosomal STRs for mixtures of male DNAs and no interference of any female admixture. The comparison of the Y STR results to the autosomal typing results for 56 nonprobative semen stains and swabs, showed a slightly higher success rate in detecting the semen donor’s alleles for the Y STR multiplex. Two examples are shown to illustrate the usefulness of Y STR typing for DNA mixtures. In one case the Y STR results confirmed an isolated exclusion; in the other case, the interpretation of a mixture was clarified since the Y STR results proved the presence of DNA from at least two semen donors. Y STR typing is a valuable addition to the forensic DNA testing panel.     

DNA analysis of the last Brazilian unknown soldier’s remains buried in Pistoia (Italy)

During World War II, many nations took part in the war. Among the supporters of the Alliance there was also Brazil. In August 1944, under the leadership of President Getúlio Vargas, Brazil declared war on Nazi Germany and took part in the Italian campaign by sending many troops to support the Allies in the Central Italy. Once the conflict was over, the deceased Brazilian soldiers were buried in Pistoia, a few kilometers from Florence. But only in 1960 the Brazilian government authorized the transfer of the dead soldiers to their homeland. Five years later, during the building of the Brazilian Military Votive Monument, still in the Pistoia cemetery, a last body was found but could not be identified: so he was buried as an “unknown soldier”. In December 2012, the Brazilian Embassy in Italy asked for performing forensic genetics analysis for identification purposes on the remains of this last unknown Brazilian soldier. After almost 70 years a complete short tandem repeats (STR) profile was obtained, useful for any relatives searching.Key points:

• Identification of the last Brazilian Unknown Soldier buried in Italy.
• DNA analysis on 70 years old skeletal remains.
• Brazilian soldier’s history during World War II.

     

Use of Eucalyptus DNA profiling in a case of illegal logging

Eucalyptus is grown world-wide for paper pulp, solid wood, and other industries. Theft or illegal cutting of the trees causes hardship to owners of plantations and countries whose economies rely on the sale and export of eucalyptus products. Unfortunately, many of these crimes go unpunished due to lack of forensic evidence.Over 1200 short tandem repeat (STR) markers have been identified in the genomes of genus Eucalyptus and related species. However, their importance and utility in aiding forensic investigations of wood theft have not been explored. This study evaluated nine STRs for diversity and applied them to a case involving suspected wood theft.As expected, three dinucleotide STR markers showed greater variability but resulted in harder to interpret profiles. Four STR tetranucleotide markers evaluated in this study were found to contain additional repeat structures (dinucleotide or trinucleotide) that enhanced their variability but resulted in profiles with peaks at multiple stutter positions and heterozygote peak imbalance. The most promising STR markers were EGM37 and EMBRA 1374. Though less variable, they yielded robust and reproducible DNA profiles.All nine STR markers were applied to a case involving suspected wood theft. Samples were collected from seized wood and from remaining stumps in a plantation. No DNA match was found, thus eliminating the evidence samples as having originated from the forest. Dendrochronology analysis also resulted in an exclusion. This case study represents the first report using STR markers in any eucalyptus species to provide DNA evidence in a case of suspected wood theft.     

CSF1PO,TPOX和TH01基因座复合扩增及其在苗族人群中的基因频率分布

在同一反应体系中，对CSFIPO，TPOX和TH01三个STR基因座做复合扩增，采用高分辨率的聚丙烯酸胺凝胶电泳分离、银染法显影技术，对云南苗族的3个基因座基因频率分布进行调查。CSFIPO基因座，观察到8个等位基因，17个基因型；TPOX基因座，观察到6个等位基因，14个基因型；TH01基因座，观察到6个等位基因，19个基因型。     

浙江汉族人群6个STR基因座的遗传多态性的调查

目的进一步完善浙江省汉族人群STR基因座遗传多态性的调查,为其应用提供基础数据。方法采用AmpF1STRSGMplus和AmpF1STRCoficer反应试剂盒,使用ABI310型基因分析仪对浙江汉族人群200名无关个体血样进行了D16S539、D2S1338、D19S433、TH01、TPOX和CSF1PO6个STR基因座遗传学分析。结果分别发现了9、15、15、11、8、10个等位基因,发现的基因型分别为23、42、35、19、16、17个,其分布经X2检验均符合Hardy-Weinberg平衡定律,并分别统计了6个STR基因座的H、DP、PM、PE及PIC参数。结论6个STR基因座适合法医学应用。     

双胞胎鉴定10例

双胞胎分为两类：同卵双生和异卵双生。同卵双生子起源于同一个受精卵，受精后，卵裂的产物没有立刻分化，结果发育成两个正常的个体，因此两个体具有完全相同的基因组。异卵双生子是由两个卵子同时或几乎同时发生受精形成的双生子，两个体之间的遗传关系与同胞兄弟姐妹之间的关系相同。双胞胎的发生率为１～３％［１、２］，性别相同约占２／３，其中同性别双胞胎约３／４为同卵双生犤３犦，性别不相同全部为异卵双生。在性别相同的双胞胎中区别是否同卵双生，过去通常检测血型、酶型及HLA，目前常规采用PCR－STR分型技术，可以获得理…     

广西地区3个群体15个STR基因座频率多态性

目的调查广西地区仡佬族、仫佬族、瑶族无关个体的15个STR基因座(D8S1179、1321S11、D7S820、CSF1PO、D3S1358、TH01、D13S317、D16S539、D2S1338、D19S433、vWA、TPOX、D18S51、D5S818、FGA)多态性,研究其在法医学检验中的应用价值。方法 应用AmpFISTR IdentifilerTM荧光标记复合扩增系统,对314例仡佬族、332例仫佬族、238例瑶族无关个体血样DNA进行15个STR基因座的复合扩增,用ABI 3100遗传分析仪对扩增产物进行检测,GeneScan、GenoTyper软件进行基因分型,统计计算15个STR基因座的群体遗传学参数。结果IdertifilerTM系统的15个STR基因座在仡佬、仫佬、瑶族的累积偶合率为1.839×10-16~5.073×10-17,累积非父排除率为0.9999983~0.9999991。结论该15个STR基因座足可满足仡佬族、仫佬族、瑶族法医学的个体识别及亲权鉴定的需要。     

不同分型方法的STR分型差异

目的调查不同的STR分型系统之间分型的一致性。方法 10 0例不同个体的DNA样本分别用单位点聚丙烯酰胺凝胶银染法和PowerPlex16System试剂盒对 13个法医学常用STR位点进行基因分型 ,并比较两种不同分型系统间的分型结果。结果 1例样本在D8S1179位点出现了分型不一致的结果 :银染法的基因型为 12 / 14 ,而用PowerPlex16System试剂盒的分型则为 12 / 15。结论不同的STR分型系统可导致不同的基因分型     

11个Y—STR基因座遗传多态性研究

目的 调查11个Y染色体STR基因座的遗传多态性。方法 利用PCR扩增和聚丙烯酰胺凝胶电泳技术对广州地区汉族群体无关男性血样进行11个Y—STR基因座的分型。结果 11个Y—STR基因座在广州地区汉族群体分别发现3～5个等位基因,GD值最低为0.3037(DYS434),最高为0.8455(DYS390)。结论 11个Y—STR基因座在广州地区汉族群体均具有较高的遗传多态性,可应用于法科学个体识别和亲子鉴定。