Null alleles and sequence variations at primer binding sites of STR loci within multiplex typing systems

Rare variants are widely observed in human genome and sequence variations at primer binding sites might impair the process of PCR amplification resulting in dropouts of alleles, named as null alleles. In this study, 5 cases from routine paternity testing using PowerPlex^®21 System for STR genotyping were considered to harbor null alleles at TH01, FGA, D5S818, D8S1179, and D16S539, respectively. The dropout of alleles was confirmed by using alternative commercial kits AGCU Expressmarker 22 PCR amplification kit and AmpFℓSTR^®. Identifiler^® Plus Kit, and sequencing results revealed a single base variation at the primer binding site of each STR locus. Results from the collection of previous reports show that null alleles at D5S818 were frequently observed in population detected by two PowerPlex^® typing systems and null alleles at D19S433 were mostly observed in Japanese population detected by two AmpFℓSTR™ typing systems. Furthermore, the most popular mutation type appeared the transition from C to T with G to A, which might have a potential relationship with DNA methylation. Altogether, these results can provide helpful information in forensic practice to the elimination of genotyping discrepancy and the development of primer sets.     

Genetic variation of 15 autosomal STR loci in a population sample from Poland

Fifteen autosomal STR loci included in AmpF?STR® NGM? kit were analyzed in 154 unrelated individuals from Poland. This multiplex kit enables simultaneous amplification of 10 standard STR loci included in AmpF?STR® SGM Plus® kit (D3S1358, vWA, D16S539, D2S1338, D8S1179, D19S433, TH01, FGA, D21S11 and D18S51) and five new mini- and midi-STR loci (D10S1248, D22S1045, D2S441, D1S1656 and D12S391). Population study was conducted to evaluate usefulness of the loci (especially the five new microsatellite systems) in forensic genetic identification examinations. All 15 markers were found to be in Hardy–Weinberg equilibrium. The combined probability of match for the 15 studied STR loci was 3.998 × 10^?19. The same parameter calculated for five new microsatellite loci equaled 8.83 × 10^?7. Discrimination power was particularly high in case of D1S1656 (0.975) and D12S391 (0.972) STR loci.     

Developmental validation of the AmpFℓSTR® NGM SElect™ PCR Amplification Kit: A next-generation STR multiplex with the SE33 locus

The AmpFℓSTR^® NGM SElect™ PCR Amplification Kit is a new 17-plex STR genotyping kit designed for use primarily in forensic casework analysis. The kit was designed to be a counterpart to the AmpFℓSTR^® NGM™ Kit for laboratories wishing to add the SE33 locus to the new European Standard Set of STR loci. The NGM SElect Kit shares the same primer sets for 16 common loci with the NGM Kit (D10S1248, D3S1358, vWA, D16S539, D2S1338, amelogenin, D8S1179, D21S11, D18S51, D19S433, TH01, FGA, D22S1045, D2S441, D1S1656 and D12S391), with additional primers for the SE33 locus. Developmental validation studies followed the Scientific Working Group on DNA Analysis Methods (SWGDAM) guidelines for STR kit manufacturers and tested several critical areas of kit performance including a sensitivity series, DNA mixtures and inhibited samples. The studies demonstrated that the NGM SElect Kit provides equivalent overall performance to the NGM Kit, but with even greater discriminatory power due to the inclusion of the highly informative SE33 locus.     

15 STR loci frequencies in the population from Paraná, Southern Brazil

Allele frequencies for 15 short tandem repeats (STR) loci were obtained from a sample of 4076 unrelated individuals undergoing paternity testing. The population is from Paraná, Southern Brazil. The loci are the most commonly used in forensic and paternity testing, being analyzed by the AmpFlSTR^® Identifiler™ (Applied Biosystems) commercial kit. The most polymorphic loci were D2S1338 and D18S51. Excepting the D13S317, all loci were in Hardy–Weinberg equilibrium. Comparative analyses between our population data and other populations are presented.     

Genetic analysis of 20 autosomal STR loci in the Miao ethnic group from Yunnan Province,Southwest China

The genetic polymorphisms of 20 autosomal short tandem repeat (STR) loci included in the PowerPlex^® 21 kit were evaluated from 748 unrelated healthy individuals of the Miao ethnic minority living in the Yunnan province in southwestern China. All of the loci reached Hardy–Weinberg equilibrium. These loci were examined to determine allele frequencies and forensic statistical parameters. The genetic relationship between the Miao population and other Chinese populations were also estimated. The combined discrimination power and probability of excluding paternity of the 20 STR loci were 0.999 999 999 999 999 999 999 991 26 and 0.999 999 975, respectively. The results suggested that the 20 STR loci were highly polymorphic, which makes them suitable for forensic personal identification and paternity testing.     

Allele frequencies of 15 STRs in the Calchaqui Valleys population (North-Western Argentina)

Allele frequencies for 15 short tandem repeat (STR) loci were obtained from a sample of 110 individuals from the Calchaqui Valleys population (North-Western Argentina). The combined power of exclusion and combined power of discriminating for the 15 tested STR loci were 0.999964 and 0.9999999999999998, respectively. Matching probability was 1 in 4.58 × 10(15). Therefore, it may be concluded that the set of 15 STRs included in the AmpF STR Identifiler kit, represents a powerful tool for forensic applications, paternity testing and population genetics studies in the Calchaqui Valleys population.     

Genetic variation analysis of 15 autosomal STR loci of AmpFℓSTR® Sinofiler™ PCR Amplification Kit in Henan (central China) Han population

AmpF?STR® Sinofiler? PCR Amplification Kit is specially developed for Chinese forensic laboratories, but there are little population-genetic indices about this kit as a whole. This kit contains 15 STR loci: D8S1179, D21S11, D7S820, CSF1PO, D3S1358, D13S317, D16S539, D2S1338, D19S433, vWA, D18S51, D6S1043, D12S391, D5S818 and FGA. In order to evaluate this kit and to get basic population-genetic indices for its use in forensic practice in Chinese Han population, the DNA of 231 unrelated Han individuals from Henan (central China) were typed using the Kit. The most discriminating locus was D6S1043 while the least was D3S1358. The combined match probability was 9.81 × 10^?19 and the combined power of exclusion was 0.99999974. Statistical analysis of the generated data indicated no departure from expectation of Hardy–Weinberg Equilibrium (HWE) in all loci but D6S1043 and no linkage disequilibrium in all pairs of loci. The observed and expected heterozygosity, power of discrimination, polymorphic information content, the other population-genetic indices were calculated.     

A genetic study of the Identifiler(™ )System 15 STR loci in the general population of Nicaragua, Central America

Allele frequencies for the 15 short tandem repeats loci D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818 and FGA (AmpF?STR(?) Identifiler(?)PCR Amplification Kit, Applied Biosystems) were determined in a sample of 322 unrelated individuals from Nicaragua. Statistical analyses were performed using PowerStats v12 and Genepop v4.0. All loci are in Hardy-Weinberg equilibrium and show high discrimination for paternity analysis and forensic genetic applications.     

Genetic polymorphisms of 20 autosomal STR loci in the Vietnamese population from Yunnan Province,Southwest China

The genetic polymorphisms of 20 autosomal short tandem repeat (STR) loci included in the PowerPlex® 21 kit were evaluated in 522 healthy unrelated Vietnamese from Yunnan, China. All of the loci reached the Hardy–Weinberg equilibrium. These loci were examined to determine allele frequencies and forensic statistical parameters. The combined discrimination power and probability of excluding paternity of the 20 STR loci were 0.999999999999999999999991 26 and 0.999999975, respectively. Results suggested that the 20 STR loci are highly polymorphic, which is suitable for forensic personal identification and paternity testing.

     

Genetic variation of 15 autosomal STR loci in a Somali population

Allele frequencies for 15 autosomal STR loci included in the AmpFℓSTR Identifiler kit (CSF1PO, D13S317, D16S539, D18S51, D19S433, D21S11, D2S1338, D3S1358, D5S818, D7S820, D8S1179, FGA, TH01, TPOX, VWA) were obtained from the analysis of 404 individuals with Somali origin. The overall match probability for the 15 studied loci was 1 in 1.18 × 10¹⁷ and the combined power of exclusion was 0.999997676. Deviation from Hardy–Weinberg equilibrium was observed for locus D2S1338 after correction for multiple testing. When comparing allele frequencies with five other African populations (Karamoja (Uganda), Mozambique, Tanzania and two other Somali population sample sets), only the Somali populations did not show significant differences for any of the tested loci.     

Population genetics of ten STR loci (AmpFℓSTR SGM plus) in Austria

A population study on the ten short tandem repeat (STR) loci D3S1358, VWA, D16S539, D2S1338, D8S1179, D21S11, D18S51, D19S433, TH01 and FGA was performed on 204 unrelated Austrian Caucasians. The DNA was amplified by multiplex PCR using the AmpFℓSTR SGM plus kit. All loci met Hardy-Weinberg expectations. The combined power of exclusion for the ten STR loci was 0.999976. The results show that these loci are very useful for forensic purposes. Received: 28 February 2000 / Accepted: 22 May 2000     

Applying massively parallel sequencing to paternity testing on the Ion Torrent Personal Genome Machine

Massively parallel sequencing (MPS) is a promising supplementary method for forensic genetics and has gradually been applied to forensic casework. In this study, we applied MPS to forensic casework on an Ion Torrent Personal Genome Machine to evaluate its performance in paternity testing with mismatched STR loci. A total of 15 samples from seven cases containing one mismatched locus by capillary electrophoresis typing were analyzed. Combined paternity index (CPI) and relative chance of paternity were calculated according to the International Society for Forensic Genetics guidelines and the Chinese national standards recommended for paternity testing. With simultaneous analysis of enough STR loci, the results support the certainty of paternity, and the mismatched alleles were considered to be mutations (CPI > 10,000). With the detection of allele sequence structures, the origins of the mutations were inferred in some cases. Meanwhile, nine STRs (CSF1PO, D1S1656, D2S441, D2S1338, D3S1358, D8S1179, D12S391, D21S11 and D4S2408) were found in an increased number of unique alleles and three new alleles in three STRs (D2S441, D21S11, and FGA) that have not been reported before were detected. Therefore, MPS can provide valuable information for forensic genetics research and play a promising role in paternity testing.     

Population data and mutation rates of 19 STR loci in seven provinces from China based on Goldeneye™ DNA ID System 20A

Short tandem repeat (STR) analysis is a primary tool in forensic casework. Population data and mutation rates of STRs are very important for paternity testing and forensic genetics. However, the population data and mutation rates of STRs in Han nationality based on large samples have still not been fully described in China. In this study, the allelic frequencies, forensic parameters, and mutation rate of 19 STR loci (D19S433, D5S818, D21S11, D18S51, D6S1043, D3S1358, D13S317, D7S820, D16S539, CSFIPO, PentaD, vWA, D8S1179, TPOX, Penta E, TH01, D12S391, D2S1338, and FGA) based on the Goldeneye™ DNA ID System 20A in Southern China Han nationality among seven provinces were investigated. Furthermore, population stratification of Southern China Han nationality among seven provinces was established. The multidimensional scaling (MDS) plot based on genetic distances (Fst) showed that the studied populations can be clustered into two major groups. However, relationships among populations were weak (Fst < 0.0043). A total of 376 cases of mutation were detected from the 19 selected loci in 15,396 meioses. The average mutation rate for the 19 loci was estimated to be 1.3 × 10⁻³ per meiosis. The mutation was mainly single step; the paternal mutation rate was higher than the maternal; and paternal mutation rate increases with paternal age.

     

Fourteen non-CODIS autosomal short tandem repeat loci multiplex data from Taiwanese

Interest in the development of polymorphic short tandem repeat (STR) markers unlinked to the CODIS loci is growing among forensic practitioners. We developed a multiplex system in which14 autosomal STR (D3S1744, D4S2366, D8S1110, D12S1090, D13S765, D14S608, Penta E, D17S1294, D18S536, D18S1270, D20S470, D21S1437, Penta D, and D22S683) could be amplified in one single polymerase chain reaction. DNA samples from 572 unrelated Taiwanese Han subjects were analyzed using this 14 STR multiplex system. Thirty parent–child pairs of parentage testing cases with a combined paternity index (CPI) below 1,000 and 32 parent–child pairs with single-step mutations found in AmpFℓSTR Identifiler loci were also recruited for validation of the newly developed system. DNA sequencing was performed for novel STRs and novel alleles found in these subjects. The distributions of allelic frequencies for these autosomal STRs and sequence data, allele nomenclature for the STRs, and forensic parameters are presented. The discrimination power in our multiplex loci ranged from 0.6858 (D18S536) to 0.9168 (Penta E), with a combined discrimination power of 0.999999999. It provides additional power to distinguish the possible single-step mutations in parent–child pairs and improves the ability to prove parentage by increasing the CPI. The combined power of exclusion of these 14 loci in Taiwanese Han in this study was 0.9999995913. In conclusion, this 14-autosomal STRs multiplex system provides highly informative STR data and appears useful in forensic casework and parentage testing.     

Population genetic data of the AmpFℓSTR® Identifiler® Plus and PowerPlex® 16 HS STR loci in four Canadian populations

Allele frequencies and forensically relevant population statistics were estimated for the short tandem repeat (STR) loci of the AmpF?STR® Identifiler® Plus and PowerPlex® 16 HS amplification kits, including D2S1338, D19S433, Penta D, and Penta E, for three First Nations Aboriginal populations and for Caucasians in Canada. The cumulative power of discrimination was ≥0.999999999999984 and the cumulative power of exclusion was ≥0.999929363 for both amplification systems in all populations. No significant departure from Hardy–Weinberg equilibrium was detected for D2S1338, D19S433, Penta D, and Penta E or the 13 Combined DNA Index System core STR loci after correction for multiple testing. Significant genetic diversity was observed between these four populations. Comparison with published frequency data for other populations is also presented.     

Korean population genetic data and concordance for the PowerPlex® ESX 17, AmpFlSTR Identifiler®, and PowerPlex® 16 systems

In case of paternity or maternity investigations with short tandem repeat (STR) analysis, deficient cases, missing person, or mutations are encountered and common STRs cannot provide sufficient forensic parameters. Thus, it is recommended that additional STRs are needed to complement conventional analysis for more reliable forensic information. We analyzed variation of 23 STRs contained in the new PowerPlex^® ESX 17 kit (Promega) and two conventional kits of the AmpFlSTR Identifiler^® (Applied Biosystems) and PowerPlex^® 16 systems (Promega) in 452 randomly chosen individuals from Korea to provide an expanded and reliable Korean database. Allele frequencies and forensic parameters were used to evaluate suitability and robustness of the new kit for forensic genetic analysis as well as in concordance studies. The combined probability of match for the 16 loci in the PowerPlex^® ESX 17 system was 2.76 × 10⁻²⁰. One genotyping discrepancy due to a null allele was observed at the D18S51 locus (the concordant rate = 99.99%), showing a primer-binding site mutation in the sequence of the locus (G-to-A substitution at position 146 of Genbank accession number JX018211). Thus, the new kit is a valuable forensic tool and is suitable to extend the Korean population genetic data obtained with well-established polymerase chain reaction multiplex-kits of the AmpFlSTR Identifiler^® and PowerPlex^® 16 systems.     

产前亲子鉴定方法研究(附23例报告)

目的对23个产前案例进行亲子鉴定。方法超声监视下行羊膜穿刺术,抽取羊水30~40ml。离心收集羊水沉渣后提取其基因组DNA,同时抽取其父母双方外周血基因组DNA。应用毛细管电泳技术和五色荧光复合扩增的方法,检测所有DNA样本的16个STR基因座基因型。结果所有羊水基因组DNA均来自独立个体,无母体DNA的污染。三联体分析显示23个案例中17例为肯定亲权关系,亲子关系概率均大于0.9999,6例确定为排除亲权关系,平均排除(位点数)指标为7.67个。二联体分析显示23个案例中17例肯定父权的平均亲子关系概率为0.9997以上,6例排除亲权关系的平均排除(位点数)指标为5个,但其中1例的排除位点只有1个。结论16个STR位点的多重荧光扩增方法在对羊水中母体DNA的污染程度进行评估的同时,可以准确、可靠的应用于产前亲子鉴定。在检测单亲鉴定案例时,若排除(位点数)指标小于2时必须补充母亲样本或增加检测的STR位点指标数,直至得出明确结论。     

Analysis of 17 STR data on 5362 southern Portuguese individuals—an update on reference database

The main objective of this work consisted of the updating of allele frequencies and other relevant forensic parameters for the 17 autosomal STR loci provided by the combination of the two types of kits used routinely in our laboratory casework: AmpF/STR Identifiler^® and the Powerplex^® 16 Systems. This aim was of significant importance, given that the last study on these kits within the southern Portuguese population dates back to 2006, and, as a consequence, it was necessary to correct the deviation caused by population evolution over the last ten years so that they might be better applied to our forensic casework. For this reason genetic data from 5362 unrelated Caucasian Portuguese individuals from the south of Portugal who were involved in paternity testing casework from 2005 to 2014 was used. Of all the markers, TPOX proved to be the least polymorphic, and Penta E the most. Secondly, this up-to-date southern Portuguese population was compared not only with the northern and central Portuguese populations, but also with that of southern Portugal in 2006, along with populations from Spain, Italy, Greece, Romania, Morocco, Angola and Korea in order to infer information about the relatedness of these respective populations, and the variation of the southern Portuguese population over time.     

Development of a 13-locus PCR multiplex system for paternity testing

In this study the development of a 13-locus multiplex-PCR system fitting the updated demands for paternity testing in Germany is described. For this purpose an existing multiplex PCR system that allows the simultaneous amplification of eight different STR loci together with the sex-specific locus amelogenin (genRES MPX-2, Serac, Germany) was extended. Whereas some of the primers were taken from the underlying multiplex system, suitable primer sequences were chosen for the STR loci D19S433, TPOX, TH01, D16S539, D5S818, D2S1338 and FGA. Primers of loci resulting in potentially overlapping fragment sizes were labelled with the fluorescent dyes 6-FAM, JOE and NED. Reaction conditions, such as annealing temperature, concentrations of primers and polymerase or buffer conditions were optimised to obtain a robust amplification and reproducible genotype analysis for various sample sources. Full DNA profiles from single source samples were reliably typed from template DNA amounts of as low as 120 pg, suggesting a potential use of this system also in forensic casework analysis. With a mean exclusion chance (MEC) of 99.9989% and a power of discrimination (P_D) of about 1×10¹⁴ (Caucasians), the new multiplex PCR system provides a significant and sensitive system for forensic DNA analysis. On the basis of these studies, a commercial kit system is now provided by Serac (Bad Homburg, Germany, genRES MPX-3).     

VWA STR genotyping: further inconsistencies between Perkin-Elmer and Promega kits

We report a simultaneous study of the VWA STR locus by the Perkin-Elmer Profiler Plus kit and the Promega GenePrint CTTv kit in a population sample from North Portugal and in 418 meiosis from family material and paternity cases. PCR amplification and genotyping were performed according to the manufacturer’s instructions using ABI 377 or ABI 310 automatic sequencers. Biological kinship in family material and paternity cases was validated by the use of the STR loci D3S1358, D5S818, D7S820, D8S1179, D13S317, D18S51, D21S11, FGA, CSF1PO, TH01 and TPOX. Out of 434 unrelated individuals we found 4 inconsistencies between the genotypes obtained using each kit. No exclusions were found in the meiotic analyses. In all cases, these inconsistencies were due to an annealing failure of the Perkin-Elmer forward primer resulting in false homozygotes. Sequencing analysis revealed an A-to-T substitution at position 1631 (GenBank sequence M25858), 52 bases upstream of the first TCTA motif of the repeat region. An estimate of the null allele frequency (s) in this study is thus obtainable from the expression s = 4/¶(2 × 434) = 0.46%. The relatively high frequency of these discrepancies in our population demonstrates the need for caution when comparing genotype or gene frequency estimates made from amplicons produced by different primers, when evaluating apparent exclusions in paternity testing and when searching for a match between individual genetic profiles in forensic databases. Our findings are also compared with those previously reported.