Autosomal Short Tandem Repeat Loci Research Articles

Population data of 13 nonCODIS STR markers located inside the 6 nonsyndromic oculocutaneous albinism genes.

Allele frequencies and forensic statistics of 13 autosomal short tandem repeat loci were estimated in 56 unrelated Iranian individuals. Except for two loci which were monomorph, a total of 5-11 alleles at each locus were observed and altogether 94 alleles for all selected loci were found. Our results show that 11 out of 13 nonCODIS STR loci are polymorphic and can be useful for human identification and kinship analysis and relationship investigations in Iran.

Population data of 17 short tandem repeat loci in 2923 individuals from the Han population of Nantong in East China.

Nantong is located in mid-eastern China, and the Han population in Nantong may be greatly affected by population admixture between northern and southern Han Chinese populations. In this study, we analyzed 17 autosomal short tandem repeat (STR) loci on 2923 unrelated individuals collected from the Han population of Nantong. No significant deviation from Hardy-Weinberg equilibrium was observed at all STR loci, and the expected heterozygosity ranged from 0.6184 to 0.9187. The combined match probability (CMP) was 3.87 × 10(-21), and the combined power of discrimination (CPD) was 99.999999999999999999613%. No significant difference of allele frequencies was observed between Nantong and other Han populations at all STR loci, as well as Dai, Mongolian, and Tibetan. Significant differences were only observed between Nantong Han and Uyghur at TH01, as well as Nantong Han and Dong at CSF1PO and FGA. Nantong Han showed significant differences between She, Bouyei, and Miao at multiple STR loci.

Polymorphism analysis of 20 autosomal short-tandem repeat loci in southern Chinese Han population

To evaluate the value of PowerPlex®21 System (Promega) and study the genetic polymorphism of its 20 short-tandem repeat (STR) loci in southern Chinese Han population. We conducted genotyping experiments using PowerPlex®21 System on 20 autosomal STR loci (D3S1358, D1S1656, D6S1043, D13S317, Penta E, D16S539, D18S51, D2S1338, CSF1PO, Penta D, TH01, vWA, D21S11, D7S820, D5S818, TPOX, D8S1179, D12S391, D19S433 and FGA) in 2367 unrelated Chinese Han individuals living in South China. The allele frequencies and parameters commonly used in forensic science were statistically analyzed in these individuals and compared with the reported data of other populations. The PowerPlex®21 System had a power of discrimination (PD) ranging from 0.7839 to 0.9852 and a power of exclusion (PE) ranging from 0.2974 to 0.8099 for the 20 loci. No significant deviation from Hardy-Weinberg expectations was found for all the loci except for D5S818. This southern Chinese Han population had significant differences in the allele frequencies from 8 ethnic groups reported in China, and showed significant differences at 8 to 20 STR foci from 5 foreign populations. The allele frequency at the locus D1S1656 in this southern Chinese Han population differed significantly from those in the 5 foreign populations and from 3 reported Han populations in Beijing, Zhejiang Province and Fujian Province of China. The neighbor-joining phylogenetictree showed clustering of all the Asian populations in one branch, while the northern Italian and Argentina populations clustered in a separate branch. This southern Chinese Han population had the nearest affinity with the Yi ethnic population in Yunnan Province of China. The 20 STR loci are highly polymorphic in this southern Chinese Han population, suggesting the value of this set of STR loci in forensic personal identification, paternity testing and anthropological study.

Population genetic analysis of the GlobalFiler STR loci in 748 individuals from the Kazakh population of Xinjiang in northwest China.

The six-dye GlobalFiler™ Express PCR amplification kit incorporates 21 commonly used autosomal short tandem repeat (STR) loci and three gender determination loci. In this study, we analyzed the GlobalFiler STR loci on 748 unrelated individuals from a Chinese Kazakh population of Xinjiang, China. No significant deviations from Hardy-Weinberg equilibrium and linkage disequilibrium were observed within and between 21 autosomal STR loci. SE33 showed the greatest power of discrimination in Kazakh population. The combined power of discrimination of Kazakh was 99.999999999999999999999996797%. No significant differences of allele frequencies were observed between Kazakh and Uyghur at all 15 tested STR loci, as well as Mongolian. Significant differences were only observed between Kazakh and the other Chinese populations at TH01. Multiple STR loci showed significant differences between Kazakh and Arab, as well as South Portuguese. The multidimensional scaling plot (MDS) plot and neighbor-joining tree also showed Kazakh is genetically close to Uyghur.

A genetic portrait of Oraon Indian tribe drawn with 15 autosomal and 17 Y chromosomal STR markers.

An analysis of 15 autosomal short tandem repeat (STR) loci and 17 Y-STR loci was performed in 123 unrelated members of the Oraon tribal community of Central India. The combined power of discrimination (CPD) and combined power of exclusion (CPE) were greater than 0.99999 and 0.999989, respectively, for autosomal STRs. In addition, a total of 58 distinct Y-STR haplotypes were observed out of which 54 Y-STR haplotypes were observed only once. The haplotype diversity and discrimination capacity for 17 Y-STR loci was 0.997 and 0.906, respectively.

A Case of Maternal Half-sisters Sharing Alleles at 18 X-chromosomal Short Tandem Repeat Loci

Analysis of X-chromosome short tandem repeats (STRs) is very helpful in deficiency paternity testing. Here, we reported a case of kinship analysis that showed a potentially erroneous inclusion of paternal sisters between two women. The two women shared alleles at 18 X-chromosomal STR loci spanned from 14.76cM (DXS6807) to 184.19cM (DXS7423). When their relatives were not available for testing, biostatistical analysis for the 18 X-chromosomal STR loci and 24 autosomal STR loci revealed the most possible relationship between the two women was paternal sisters. However, when the father of one woman was available, the other father-daughter possibility was excluded. In the end, the likelihood ratio of STR marker and mitochondrial DNA (mtDNA) sequences confirmed the two women were maternal sisters. This case emphasizes a cautionary interpretation of X chromosomal marker in deficiency paternity cases with female offspring. Even though large parts of the X-chromosome haplotypes shared by two females, additional relatives and extended DNA typing (such as mtDNA) may be needed further to ascertain whether they are paternal or maternal sisters.

Genetics analysis of 38 STR loci in Uygur population from Southern Xinjiang of China

The allele frequencies and statistical parameters of 38 autosomal short tandem repeat (STR) loci were analyzed in the Uygur population from Southern Xinjiang of China with 290 unrelated individuals. The results show these 38 STR loci have high or medium power of discrimination and probabilities of exclusion. All loci are in Hardy-Weinberg equilibrium. The genetic distances between the Uygur population and other Chinese populations were also estimated.

Allele frequency data for 15 autosomal STR loci in eight Indonesian subpopulations

Evolutionary and cultural history can affect the genetic characteristics of a population and influences the frequency of different variants at a particular genetic marker (allele frequency). These characteristics directly influence the strength of forensic DNA evidence and make the availability of suitable allele frequency information for every discrete country or jurisdiction highly relevant. Population sub-structure within Indonesia has not been well characterised but should be expected given the complex geographical, linguistic and cultural architecture of the Indonesian population. Here we use forensic short tandem repeat (STR) markers to identify a number of distinct genetic subpopulations within Indonesia and calculate appropriate population sub-structure correction factors. This data represents the most comprehensive investigation of population sub-structure within Indonesia to date using these markers. The results demonstrate that significant sub-structure is present within the Indonesian population and must be accounted for using island specific allele frequencies and corresponding sub-structure correction factors in the calculation of forensic DNA match statistics.

Evaluating the genetic impact of South and Southeast Asia on the peopling of Bangladesh.

Despite rapidly growing understandings and dependency on single nucleotide polymorphisms (SNPs), highly variable autosomal short tandem repeats (STRs) are still regarded as the most established method to differentiate individuals at forensic level. Here with large number of various ethnic groups we undertook this study to reveal the genetic structure of the most densely populated part of South Asia i.e. the Bangladesh. The purpose of this work was to estimate population parameters based on the allele frequencies obtained for 15 polymorphic autosomal STR loci investigated in caste and tribal populations from Bangladesh (n=706). We compared the results in a broader context by merging 24 different populations of Asia to pertain their affinity. Various statistical analyses suggested a clear cut demarcation of tribal and non-tribal in Bangladesh. Moreover, beside the phylogenetic structure of the studied populations, it is found that the mean heterozygosity value was highest among the populations of Bangladesh, likely because of gene flow from different directions. However, Tonchangya, Adi and Khumi showed sign of genetic isolation and reduced diversity, possibly as a result of genetic drift and/or strong founder effects working on small endogamous populations.

An incest case with three biological brothers as alleged fathers: Even 22 autosomal STR loci analysis would not suffice without the mother.

Here, we report an incest paternity case involving three biological brothers as alleged fathers (AFs), their biological sister and her child that was investigated using the Investigator ESSplex Plus, AmpFLSTR Identifiler Plus/Investigator IDplex Plus and PowerPlex 16 kits. Initial duo paternity investigations using 15-loci autosomal short tandem repeat (STR) analyses failed to exclude any of the AFs. Despite the fact that one of the brothers, AF1, had a mismatch with the child at a single locus (D2S1338), the possibility of a single-step mutation could not be ruled out. When the number of autosomal STR loci analysed was increased to 22 without the inclusion of the mother, AF2 and AF3 still could not be excluded, since both of them again had no mismatches with the child. A breakthrough was possible only upon inclusion of the mother so that trio paternity investigations were carried out. This time AF1 and AF2 could be excluded at two loci (D2S1338 and D1S1656) and six loci (vWa, D1S1656, D12S391, FGA, PENTA E and PENTA D), respectively, and AF3 was then the only brother who could not be excluded from paternity. Subsequent statistical analyses suggested that AF3 could be the biological father of the child with a combined paternity index >100 billion and a probability of paternity >99.99999999%. These findings consolidate the fact that complex paternity cases such as those involving incest could benefit more from the inclusion of the mother than simply increasing the number of STR loci analysed.

Allele frequencies for 21 autosomal short tandem repeat loci obtained using GlobalFiler in a sample of 1501 individuals from the Japanese population.

Allele frequencies for 21 autosomal short tandem repeat loci (D3S1358, vWA, D16S539, CSF1PO, TPOX, D8S1179, D21S11, D18S51, D2S441, D19S433, TH01, FGA, D22S1045, D5S818, D13S317, D7S820, SE33, D10S1248, D1S1656, D12S391, and D2S1338) were obtained using the GlobalFiler kit from 1501 unrelated individuals sampled from the Japanese population.

Sibling assessment based on likelihood ratio and total number of shared alleles using 21 short tandem repeat loci included in the GlobalFiler™ kit.

Sibling assessment using the 15 autosomal short tandem repeat (STR) loci included in the Identifiler® kit can be difficult when comparing an unidentified party to an alleged sibling. Therefore, we investigated the likelihood ratio (LR) and the total number of shared alleles (TNSA) for sibship determination using the 21 autosomal STR loci included in the GlobalFiler™ kit. We computationally generated the genotypes of 10,000 sibling pairs and 10,000 unrelated pairs based on previously reported allele frequencies of the 15 Identifiler loci and the remaining 6 GlobalFiler loci. The LR and the TNSA were then calculated in each pair using the 15 and 21 loci. Next, these calculations were applied to 22 actual sibling pairs. LR values ⩾ 10,000 were observed in 48% of the sibling pairs using the 15 loci and in 80% of the sibling pairs using the 21 loci. The TNSA distribution between siblings and unrelated pairs was more divergent in GlobalFiler than in Identifiler. TNSA values ⩾ 20 were found only in true siblings in Identifiler, while TNSA values ⩾24 in GlobalFiler. In Identifiler, all pairs with TNSA ⩾ 24 had LR values ⩾ 10,000 and the same was true in GlobalFiler for TNSA ⩾29. Therefore, increasing the number of loci is very efficient for sibship determination. The LR is most reliable for determining sibship. However, TNSA values may be useful for the preliminary method of LR values because LR value demonstrated a significantly positive correlation with TNSA value in both Identifiler and GlobalFiler.

A case of false mother included with 46 autosomal STR markers.

BackgroundFor solving a maternity case, 19 autosomal short tandem repeats (STRs) were amplified using the AmpFℓSTR® SinofilerTM kit and PowerPlex® 16 System. Additional 27 autosomal STR loci were analyzed using two domestic kits AGCU 21+1 and STRtyper-10G. The combined maternity index (CMI) was calculated to be 3.3 × 1013, but the putative mother denied that she had given birth to the child. In order to reach an accurate conclusion, further testing of 20 X-chromosomal short tandem repeats (X-STRs), 40 single nucleotide polymorphism (SNP) loci, and mitochondrial DNA (mtDNA) was carried out.FindingsThe putative mother and the boy shared at least one allele at all 46 tested autosomal STR loci. But, according to the profile data of 20 X-STR and 40 SNP markers, different genotypes at 13 X-STR loci and five SNP loci excluded maternity. Mitochondrial profiles also clearly excluded the mother as a parent of the son because they have multiple differences. It was finally found that the putative mother is the sister of the biological father.ConclusionsDifferent kinds of genetic markers needfully supplement the use of autosomal STR loci in case where the putative parent is suspected to be related to the true parent.

Identification of human remains from the Second World War mass graves uncovered in Bosnia and Herzegovina.

AimTo present the results obtained in the identification of human remains from World War II found in two mass graves in Ljubuški, Bosnia and Herzegovina.MethodsSamples from 10 skeletal remains were collected. Teeth and femoral fragments were collected from 9 skeletons and only a femoral fragment from 1 skeleton. DNA was isolated from bone and teeth samples using an optimized phenol/chloroform DNA extraction procedure. All samples required a pre-extraction decalcification with EDTA and additional post-extraction DNA purification using filter columns. Additionally, DNA from 12 reference samples (buccal swabs from potential living relatives) was extracted using the Qiagen DNA extraction method. QuantifilerTM Human DNA Quantification Kit was used for DNA quantification. PowerPlex ESI kit was used to simultaneously amplify 15 autosomal short tandem repeat (STR) loci, and PowerPlex Y23 was used to amplify 23 Y chromosomal STR loci. Matching probabilities were estimated using a standard statistical approach.ResultsA total of 10 samples were processed, 9 teeth and 1 femoral fragment. Nine of 10 samples were profiled using autosomal STR loci, which resulted in useful DNA profiles for 9 skeletal remains. A comparison of established victims' profiles against a reference sample database yielded 6 positive identifications.ConclusionDNA analysis may efficiently contribute to the identification of remains even seven decades after the end of the World War II. The significant percentage of positively identified remains (60%), even when the number of the examined possible living relatives was relatively small (only 12), proved the importance of cooperation with the members of the local community, who helped to identify the closest missing persons’ relatives and collect referent samples from them.

Mutation rate analysis at 19 autosomal microsatellites.

Previous studies have demonstrated that a large sample size is needed to reliably estimate population- and locus-specific microsatellite mutation rates. Therefore, we conducted a long-term collaboration study and performed a comprehensive analysis on the mutation characteristics of 19 autosomal short tandem repeat (STR) loci. The STR loci located on 15 of 22 autosomal chromosomes were analyzed in a total of 21,106 samples (11,468 parent-child meioses) in a Chinese population. This provided 217,892 allele transfers at 19 STR loci. An overall mutation rate of 1.20 × 10(-3) (95% CI, 1.06-1.36 × 10(-3) ) was observed in the populations across 18 of 19 STR loci, except for the TH01 locus with no mutation found. Most STR mutations (97.7%) were single-step mutations, and only a few mutations (2.30%) comprised two and multiple steps. Interestingly, approximately 93% of mutation events occur in the male germline. The mutation ratios increased with the paternal age at child birth (r = 0.99, p<0.05), but not maternal age. Last, with the combination analysis of the data from the southern Chinese population, we drew a picture of 19 STR mutations in China. In conclusion, the data from this study will provide useful information in parentage testing, kinship analysis, and population genetics.

Multistep microsatellite mutation leading to father-child mismatch of FGA locus in a case of non-exclusion parentage.

A non-exclusion paternity case with a mismatch in the autosomal short tandem repeats (STR) locus FGA is reported. The genotypes of the suspected father, the mother and the questioned child in FGA locus were 18/25, 20/26 and 20/22, respectively. Examination of 38 autosomal STR loci revealed no mismatches, and the paternity index is up to 1.3618×10(6). The haplotype of 16 Y chromosomal STR in the child matched completely with that of the father. These results suggested that the suspected father is the biological father of the child and that a rare three- or four-step microsatellite mutation had occurred in the paternal allele of FGA.

Genetic variation at 15 autosomal STR loci in Bhil tribal population of Central India

Aims: Genotypic polymorphism studies at 15 highly polymorphic short tandem repeat (STR) loci were carried out in Bhil tribal population of Madhya Pradesh, in central region of India.Methods: The analysis of 15 autosomal STR loci (TH01, D3S1358, vWA, D21S11, TPOX, D7S820, D19S433, D5S818, D2S1338, D16S539, CSF1PO, D13S317, FGA, D18S51, D8S1179) was done in 183 unrelated individuals of the Bhil tribe.Results: Heterozygosity among the studied 15 autosomal STR loci ranged from 63.5–86.5%. The loci D2S1338 and FGA were found to be mostly polymorphic. All loci fall under Hardy–Weinberg equilibrium, except loci D18S51 and D7S820. These STR loci were highly informative and discriminating, with CPD > 0.99999.Conclusion: The clustering pattern of the NJ tree and the PCA plot showed grouping of the Bhil population with previously reported tribes of central India.

Evaluation of advanced multiplex short tandem repeat systems in pairwise kinship analysis

The AmpFLSTR Identifiler Kit, comprising 15 autosomal short tandem repeat (STR) loci, is commonly employed in forensic practice for calculating match probabilities and parentage testing. The conventional system exhibits insufficient estimation for kinship analysis such as sibship testing because of shortness of examined loci. This study evaluated the power of the PowerPlex Fusion System, GlobalFiler Kit, and PowerPlex 21 System, which comprise more than 20 autosomal STR loci, to estimate pairwise blood relatedness (i.e., parent-child, full siblings, second-degree relatives, and first cousins). The genotypes of all 24 STR loci in 10,000 putative pedigrees were constructed by simulation. The likelihood ratio for each locus was calculated from joint probabilities for relatives and non-relatives. The combined likelihood ratio was calculated according to the product rule. The addition of STR loci improved separation between relatives and non-relatives. However, these systems were less effectively extended to the inference for first cousins. In conclusion, these advanced systems will be useful in forensic personal identification, especially in the evaluation of full siblings and second-degree relatives. Moreover, the additional loci may give rise to two major issues of more frequent mutational events and several pairs of linked loci on the same chromosome.

Allele frequency data of 21 autosomal short tandem repeat loci in Mesan and Basra provinces in South Iraq

Abstract: We focused on a sample of 100 unrelated persons from the provinces of southern Iraq. This is an analysis of the allele frequency and genotyping of those STR loci in an Iraqi population and this is the first study of its kind in Iraq. As such the data available could be utilized in the Iraqi database for the STR polymorphic markers. Chelex® kit was utilized to extract DNA then Power Plex21® kit (D3S1358, D13S317, PentaE, D16S539, D18S51, D2S1338, CSF1PO, Penta D, THO1, vWA, D21S11, D7S820, TPOX, D8S1179, FGA, D2S1338, D5S818, D6S1043, D12S391, D19S433) was used to amplify the isolated DNA. The mean PIC values and heterozygosity observed across 21 loci were 0.713 and 0.696, respectively. This shows high gene diversity. Those loci can be safely used to establish a DNA-based database for the Iraqi population because the power of discrimination values for all tested loci was from 71% to 97%.

English

The objectives of the study included the detection of genetic variation of 21 autosomal short tandem repeats (STRs) loci from random unrelated individuals in the middle and South Arab people of Iraq, the Forensic efficiency parameters of the autosomal 21 genetic loci using power plex21® kit and to evaluate the importance of these loci for forensic genetic purposes and the possibility to use the new kit in routine practical work. FTA® Technology was utilized to extract DNA from blood collected on FTA™ paper. Twenty one (21) STR loci including D3S1358, D13S317, PentaE, D16S539, D18S51, D2S1338, CSF1PO, Penta D, THO1, vWA, D21S11, D7S820, TPOX, D8S1179, FGA, D1S1656, D5S818, D6S1043, D12S391, D19S433 and Amelogenin were amplified by using power plex21® kit. PCR products were detected by genetic analyzer 3130xL then, the data processed and analyzed by PowerStatsV1.2 software. Several statistical parameters of genetic and forensic efficiencies based on allelic frequencies have been estimated. This includes the observed heterozygosity (Ho), expected heterozygosity (He), paternity index (PI), random match probability (RMP), power of discrimination (PD), chance of exclusion (CE), polymorphic information content (PIC) and P-value. The power of discrimination values for autosomal tested loci was from 75 to 96% therefore those loci can be safely used to establish a DNA-based database for Iraq population for identifical purpose. The high PIC values of the selected markers confirm their usefulness for genetic polymorphism studies and linkage mapping programs in human as well. The mean heterozygosity observed, expected and mean PIC values across the 20 loci were 0.79, 0.83 and 0.81, respectively indicating high gene diversity. A total of nine off-ladder alleles and one tri-allelic pattern were detected in this study. Key words: Autosomal STR, Iraq, off ladder, statistical parameters, tri-allelic pattern.