Identification and characterization of variant alleles at CODIS STR loci

Short tandem repeat (STR) profiles from 32,671 individuals generated by the ABI Profiler Plus and Cofiler systems were screened for variant alleles not represented within manufacturer-provided allelic ladders. A total of 85 distinct variants were identified at 12 of the 13 CODIS loci, most of which involve a truncated tetranucleotide repeat unit. Twelve novel alleles, identified at D3S1358, FGA, D18S51, D5S818, D7S820 and TPOX, were confirmed by nucleotide sequence analysis and include both insertions and deletions involving the repeat units themselves as well as DNA flanking the repeat regions. Population genetic data were collected for all variants and frequencies range from 0.0003 (many single observations) to 0.0042 (D7S820 '10.3' in North American Hispanics). In total, the variant alleles identified in this study are carried by 1.6% of the estimated 1 million individuals tested annually in the U.S. for the purposes of parentage resolution. A paternity case involving a recombination event of paternal origin is presented and demonstrates how variant alleles can significantly strengthen the genetic evidence in troublesome cases. In such instances, increased costs and turnaround time associated with additional testing may be eliminated.     

Allelic frequencies at 12 STR loci in Colombian population

Three hundred and twenty-six to four hundred and fifty-one individuals were typed for 12 STR markers and revealed by silver stain method and assisted by a computer analysis. Forensic and Hardy-Weinberg values were found. The Kodak ds 1D Image Analysis Software V 2.0.3 EDAS DC 120 System was a useful tool for determining the correct size of pattern bands that were out allelic ladders, alleles 18 and 17 from F13A01, 15 from TPOX and 4 from TH01 were determined by this method and some corroborated by automatic analysis.     

Iranian STR variation at the fringes of biogeographical demarcation

The integrative relationship between population genetics and forensic biology allows for a thorough genetic characterization of extant human populations. This study aimed to genetically characterize 150 unrelated healthy donors from a general population in Iran both forensically and phylogenetically. The allelic frequencies of 15 STR loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818 and FGA) were generated. This constitutes the core of polymerase chain reaction (PCR)-based DNA genetic markers in the US Combined DNA Index System (CODIS) plus two additional loci (D2S1338 and D19S433) that together are consistent with several other worldwide database requirements. There were no deviations from Hardy-Weinberg expectations. Based upon the allelic frequencies, several important forensic parameters were calculated including: gene diversity (GD) index, power of discrimination (PD), polymorphic information content (PIC) and power of exclusion (PE). G-tests indicate the allelic frequencies of the Iranians are statistically non-significant compared to two Turkish populations yet, statistically different from the remaining 18 groups obtained from the literature and examined in this study. This suggests that the Iranian dataset may be forensically equivalent to the dataset from the Turkish region of Eastern Anatolia and the general population from Turkey. Phylogenetic analysis of our population with the full set of 15 loci indicate the Iranians occupy an intermediate position relative to the major Caucasian and East Asian clades on a global level. A regional phylogenetic analysis using 13 of the 15 loci indicate the Iranians segregate in a more compact association with groups from southeastern Spain, Arabs from Morocco and Syria, and especially with the general population from Turkey and those from Eastern Anatolia. These groups are flanked by highly differentiated populations from northern India and a Berber group from Tunisia on opposing ends of the regional phylogram. This report also demonstrates the necessity to thoroughly characterize the genetic composition of populations located in geographic intersections in order to choose the appropriate dataset on which to base forensic calculations, not only at an intra-population level, but also at an inter-population level as well.     

Genetic diversity at two pentanucleotide STR and thirteen tetranucleotide STR loci by multiplex PCR in four predominant population groups of central India

Genetic diversity study at STR loci in 208 individuals belonging to two backward groups, one caste and one tribal community of Central India called "Chhattisgarh" has been carried out to evaluate significance of Powerplex System loci in human identification and population diversity. Populations are Agharia (72), Satmani (50), Dheria Gond (36) and Teli (50). Fifteen loci (Powerplex 16 Kit) studied are Penta E, D18S51, D21S11, THO1, D3S1358, FGA, TPOX, D8S1179, vWA, Amelogenin, Penta D, CSF1PO, D16S539, D7S820, D13S317 and D5S818. The studied penta nucleotide STR (two) and 13 tetranucleotide (CODIS ) STR are found to be highly polymorphic genetic markers in all studied populations. Most common allele for the four studied population has been found to be same at THO1 (allele 9), D8S1179 (allele 14), CSF1PO (allele 12), Penta E (allele 11) and D16S539 (allele 11). Penta E is found to be most polymorphic (PD=0.89373) among studied 15 STR loci in four populations of Central India.     

15个常染色体和10个Y-STR基因座复合扩增试剂盒的研发

目的建立法医物证学常染色体和Y染色体综合检测的方法。方法选择常用的常染色体STR基因座和Y染色体STR基因座,设计复合扩增引物,形成五色荧光标记复合扩增试剂盒。结果开发出一个五色荧光标记复合扩增试剂盒,可同时对15个常染色体STR基因座、1个性别基因座和10个Y染色体STR基因座进行分型检测。结论 15个常染色体STR加10个Y染色体STR检测试剂盒结合毛细管电泳凝胶进行STR分型,结果准确可靠,在法医学案件检验及数据库建设等方面有良好的应用前景。     

New alleles and mutational events at 14 STR loci from different German populations

The molecular origin of DNA mutations and the mutation rates were analyzed at 14 short tandem repeat (STR) loci with samples from trio cases derived from 10 different German population samples. STR loci comprised of D2S1360, D3S1744, D4S2366, D5S2500, D6S474, D7S1517, D8S1132, D10S2325, D12S391, D18S51, D19S246, D20S480, D21S226, and D22S689. In a total of 488 meioses, 16 isolated genetic inconsistencies in 8 different STRs were observed, whereas no mutations were found at the other loci. The data of five mutations suggested the presence of silent or null alleles due to sequence variation in primer binding site. This could be confirmed for four suspected cases by the use of alternative primer sets and by DNA sequence analyses. Furthermore, this study revealed nine new allelic variants at five different loci.     

Accurate STR allele designations at the FGA and vWA loci despite primer site polymorphisms

Polymerase chain reaction (PCR)-based STR DNA typing systems are used extensively in the field of human identification. Under optimal PCR conditions, the amplicon yield from both alleles of an STR locus is expected to be approximately equivalent. However, it is reasonable to expect that rare genomic sequence polymorphisms will co-localize with well-designed primer sets and induce allele imbalance or "dropouts". Two samples were identified in the course of genotyping thousands of individuals with AmpF/STR Profiler Plus that showed strong disparity in amplitude peak height of heterozygous peaks at the loci vWA and FGA. These samples were reamplified at reduced annealing temperature in an attempt to balance the peak heights. Nucleotide sequencing documented polymorphisms at the PCR primer binding sites of the affected alleles. The results indicate that reducing the annealing temperature to improve primer-binding efficiency at the mismatch and employing an alternative multiplex enhanced the data from both samples. Reducing annealing temperatures could provide a simple general solution to improving data quality for samples where polymorphisms are suspected to cause allele imbalance. Finally, we report on additional polymorphisms surrounding the vWA locus in a genetically diverse population.     

STR data for 09 autosomal STR markers from Rio Grande do Sul (southern Brazil)

Allele frequencies for 09 STR autosomal loci (D3S1358, D5S818, D7S820, D8S1179, D13S317, D18S51, D21S11, FGA and VWA) included in the AmpFlSTR Profiler Plus were obtained from a sample of unrelated individuals from Rio Grande do Sul (southern Brazil).     

Genetic polymorphism at nine STR loci in two ethnic groups of China

Genotype polymorphism studies at nine short tandem repeat (STR) loci (D3S1358, FGA, TH01, D7S820, VWA, CSF1PO, D5S818, D13S317, TPOX) were carried out in two Ethnic Groups (Tu, Sala) living in Qinhai, a North-West province of China. All loci were in accordance with Hardy-Weinberg equilibrium (P = 0.05).     

DNATyper^TM15基因座的研究与选择

目的为研发复合扩增荧光检测试剂盒,对现有的STR基因座进行分析研究并优选新的高鉴别力基因座。方法收集汉族、锡泊族、畲族、壮族、藏族等5个民族群体血样共1200份,提取DNA,应用复合扩增方法检测1200名5个民族群体无关个体的24个基因座的等位基因分布。结果TPOX和TH01基因座的等位基因在5个民族群体中分布不平衡;D2S1338、D6S1043和Penta E等3个STR基因座在5个民族群体中均具有高度遗传多态性,等位基因频率分布均匀,在各群体间无显著差异,而且等位基因传递遵循孟德尔遗传规律。结论确定出DNATyperTM15试剂盒中的14个适合中国人群体遗传学特征和法医学应用的STR基因座。     

Genetic variation and relationships at five STR loci in five distinct ethnic groups in China

Five short tandem repeat (STR) systems of TH01, vWA, LPL, F13B and FES/FPS were investigated in five ethnic groups living in China (Tujia, Miao, Bai, Chaoxian and Han). All five loci did not deviate from the Hardy-Weinberg equilibrium (P>0.05). At the five loci of each ethnic group, the observed heterozygosity, the mean exclusion chance (MEC), and the power of discrimination (PD) ranged from 0.42 to 0.86, from 0.20 to 0.66 and from 0.61 to 0.95, respectively. For the five ethnic groups, the combined MEC and combined PD were >0. 9360 and >0.9998, respectively, suggesting that combinations of these five systems are feasible for DNA typing in forensic investigations such as personal identification or paternity testing. Furthermore, the allelic frequencies at the five loci suggested that these five ethnic groups were distinctly different communities. Judging from the phylogenetic tree constructed based on the genetic distance among the five ethnic groups, Han, Chaoxian and Tujia were involved in an identical cluster, and Miao and Bai in another. These findings indicate that each of the five groups examined is not only a distinct community, but also has a relationship with each of the others.     

Evaluation of population variation at 17 autosomal STR and 16 Y-STR haplotype loci in Croatians

Seventeen autosomal STR loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, VWA, TPOX, D18S51, D5S818, FGA, Penta E and Penta D) and 16 Y-STR haplotype loci (DYS19, DYS385, DYS389I, DYS398II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635 and GATA H4.1) were analyzed in the sample of 200 unrelated Croatians. The agreement with HWE was confirmed for all autosomal STR loci. The combined power of discrimination (PD) and the combined power of exclusion (PE) for the 17 autosomal STR loci were 0.999999999999999999682299331476 and 0.99999995, respectively. Penta E proved to be the most informative autosomal STR locus. Among 200 Croatian males, 197 Y-STR haplotypes were identified and haplotype diversity was estimated at 0.9998 ± 0.0005.     

Contribution for an African autosomic STR database (AmpF/STR Identifiler and Powerplex 16 System) and a report on genotypic variations

Allele frequencies, together with some parameters of forensic interest, for 17 STRs included in the AmpF/STR Identifiler (CSF1PO, D2S1338, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D19S433, D21S11, FGA, TH01, TPO and VWA) and Powerplex 16 System (CSF1PO, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, FGA, Penta D, Penta E, TH01, TPO and VWA) were estimated from a sample of 135-144 unrelated individuals from Mozambique. No deviations from Hardy-Weinberg equilibrium were observed with the exception of the FGA locus (using the Bonferroni correction for the number of loci analysed, the departure observed at this locus was not significant). Comparative analyses between our population data and other African databases, namely Promega's African-Americans, AB Applied Biosystems African-Americans and two other population samples from Mozambique and Guiné Bissau, are presented and discussed. Genotype inconsistencies between both commercial kits (for D16S539 and D8S1179) and other genotypic variations (three-banded allele patterns for TPO) are also reported.     

放置时间对烟蒂上DNA含量及STR分型的影响

目的 探讨不同放置时间对烟蒂上DNA含量及STR分型的影响.方法 以lO名志愿者的40枚"红双喜"烟蒂为检材(每人4枚),用chelex-100法分别在第1、4、7和1O周时提取烟蒂样本外层烟纸和海绵上的DNA,用Quantifiler人类DNA定量试剂盒进行DNA定量.并同时用AmpFL STR Profiler和IdentifilerrM试剂盒(AB公司)进行PCR扩增及STR分型. 结果放置第1、4、7和10周的烟蒂烟纸DNA质量浓度范围分别为0.104～2.52、0.110～2.41、0.096 0～2.32和0.085 0～2.28ng/μL,16个基因座检出率分别为100%、90%、75%和62.5%.海绵DNA质量浓度范围分别为0.0180～2.40、0.0171～2.25、0.0165～2.15和0.0160～2.15ng/μL,16个基因座检出率分别为97.5%、82.5%、50%和12.5%. 结论放置时间对烟纸和海绵上的DNA含量影响不大,对STR分型影响显著,STR分型受海绵的影响比烟纸明显.放置时间越久.检出率越低.     

Genetic variation at nine STR loci in populations from the Philippines and Thailand living in Taiwan

In order to apply a set of nine STR loci and the amelogenin locus in forensic testing, we have performed a population study on individuals from the Philippines and Thailand living in Taiwan (273 Philippine and 146 Thai individuals were typed by commercially available kits and an automated sequencer). A total of 73 alleles for all systems for both populations could be observed in these two populations. No new intermediate fragments were found. Allele frequencies showed no deviation from Hardy-Weinberg equilibrium. The mean exclusion power (MEP) ranged from 0.327 (TPOX) to 0.706 (FGA), the discriminating power (DP) ranged from 0.790 (TPOX) to 0.963 (FGA) for Philippinos, MEP ranged from 0.247 (TPOX) to 0.723 (FGA), DP ranged from 0.761 (TPOX) to 0.968 (FGA) for Thais, the combined MEP is > 0.9988 and the combined DP is > 0.9999999993 for both Philippinos and Thais.     

Allele frequencies for the four major sub-populations of New Zealand at three STR loci--HUMTH01, HUMTPOX and CSF1PO

Allele frequencies for the three STR loci included in the GenePrint CTT multiplex system (HUMTH01, HUMTPOX, HUMCSF1PO) have been determined for the four major sub-populations of New Zealand.     

Mutation rates at 14 STR loci in the population from Pernambuco, Northeast Brazil

Definition about mutation rates of short tandem repeats (STRs) loci used in forensic analysis are useful for the correct interpretation of resulting genetic profiles and the definition of criterions for exclusion in paternity testing. Germline mutation of 14 STR loci was studied for 54,105 parent–child allelic transfers from 2575 paternity testing cases carried out during 2000–2007 from the Pernambuco State, Northeast Brazil. The parenthood in each of these cases was highly validated (probability > 99.99%). We identified 43 mutations at 12 loci. Locus-specific mutation rate estimates varied between 2 × 10⁻⁴ and 2 × 10⁻³, and the overall mutation rate estimate was 8 × 10⁻⁴. Mutation events in the male germline were more frequent than in the female germline. The majority of the mutations could be explained by losses or gains of one repeat unit and there was no evidence for selection between insertion or deletion changes. Our data were compared with those of Portuguese and North-American populations for CSF1PO, D18S51, D21S11, D7S820, TH01, TPOX and demonstrated, despite the great difference in the size of the sample, that mutation rates of STR loci in a mixed population do not differ from that encountered in different populations.     

Evaluating population structure of Ecuador for forensic STR markers

The continuous admixture events among Europeans, Native Americans, and Africans occurred differently throughout the Ecuadorian territory, creating a diversified genetic composition. Therefore, to evaluate how the genetic diversity is partitioned along the country for 15 STRs, 842 admixed-population samples were analyzed. We also evaluated the effect of applying an adjustment for population structure when estimating LRs using a national database. The results showed that to accurately assess forensic evidence, the use of a national database may be justified with the application of an appropriate adjustment for population structure.