Characterization of a novel unliked 12 X-STR typing assay forforensic purposes in an admixed Rio de Janeiro population sample

Background X-chromosomes show a specific genetic mode, which makes genetic markers on the X-chromosome play crucial roles in forensic research and human evolution. Dong group, one of 55 minority groups in China, live in Guizhou, Guangxi, and Hunan provinces. Even though some genetic data of Y chromosomal short tandem repeats (STRs) and autosomal insertion/deletion polymorphism (InDels) in Dong groups have been reported, there is little research about X-STRs in the Dong group. Aim Purposes of this study are to investigate allelic distributions and forensic statistical parameters of 19 X-STRs in the Guizhou Dong group, and explore the genetic composition of the Guizhou Dong group and its phylogenetic relationships with other reference populations. Subjects and methods Five hundred and seven Dongs (272 males and 235 females) living in Guizhou province were typed using the AGCU X19 STR kit. Allelic frequencies and forensic parameters of 19 X-STRs in the Guizhou Dong group were calculated. Population genetic analyses of Guizhou Dong and another 17 reference populations were conducted using DA genetic distances, phylogenetic tree, principal component analysis, and multidimensional scaling. Results A total of 230 alleles of 19 X-STRs were identified in all Dongs. The frequencies of 19 loci ranged from 0.0013 to 0.6838. The values for cumulative power of discrimination in males (PDM), cumulative power of discrimination in females (PDF), and four different kinds of mean exclusion chance (MEC_Kruger, MEC_Kishida, MEC_Desmarais, and MEC_Desmarais_du) for the 19 X-STRs in all individuals were 0.999999999999761, 0.9999999999999999999993951, 0.999999964841617, 0.999999999997261, 0.999999999997297, and 0.999999993623172, respectively. Besides, genetic polymorphisms of seven linkage clusters ranged from 0.9381 to 0.9963. In addition, these seven groups showed high polymorphism information content (PIC), PDM, PDF, MEC_Kruger, MEC_Kishida, MEC_Desmarais, and MEC_Desmarais_duo. Population genetic analyses of Guizhou Dong and another 17 reference populations showed that the Guizhou Dong group had close genetic relationships with surrounding Tai–Kadai-speaking, Hmong-Mien-speaking, and Han groups. Conclusion Nineteen X-STRs displayed high genetic diversities and could be employed for forensic personal identification and paternity analysis in the Guizhou Dong group. Close genetic affinities between Guizhou Dong and surrounding populations were observed based on the 19 X-STRs in 17 reference populations.

Utility of X-chromosome SNPs in relationship testing

X chromosomal short tandem repeats (X-STRs) have the characteristics of both autosomal and uniparental genetic markers and have been shown to be particularly useful in forensic casework. However, relevant research or reports have not focused on X-STRs in the Hani population. To investigate the genetic variation and forensic efficiency of 16 X-STR loci in the Hani ethnic minority, we calculated the allele frequencies and forensic parameters of 451 (116 males and 335 females) unrelated healthy Hani individuals from Yunnan Province, Southwest China. All these loci are highly polymorphic in Hani individuals in Yunnan Province except DXS6800. The combined power of discrimination in males (PDM) and power of discrimination in females (PDF) were found to be 0.999 999 998 433 993 and 0.999 999 999 999 998, respectively. Furthermore, a population genetic structure investigation between the Yunnan Hani population and another 18 populations was performed using a principal component analysis, multidimensional scaling plot and neighbouring-joining phylogenetic tree and the findings illustrated that neighbouring populations and different nationalities in the same area appeared to have a closer evolutionary relationship. This study provides the first batch of X chromosome genetic polymorphism data of the Hani population in Yunnan Province, Southwest China and enriches the reference database of the Chinese minority population. Key points This is the first study of X-STR in the Hani population. We calculated the allele frequencies and forensic parameters of 451 unrelated healthy Hani individuals from Yunnan Province, Southwest China. All these loci are highly polymorphic in Hani individuals in Yunnan Province except DXS6800. The genetic relationship between the Hani and the other 18 nationalities was analyzed. This study provides the first batch of X chromosome genetic polymorphism data of the Hani population in Yunnan Province, Southwest China and enriches the reference database of the Chinese minority population.

Genetic polymorphism analyses of three novel X chromosomal short tandem repeat loci in the Xp22.3 region.

DNA testing using X-chromosomal short tandem repeat (X-STR) polymorphisms has been used in maternity/paternity and complex kinship cases. Analyses of repeat sequences, surveys on racial statistics, and development of practical applications for DNA testing continue to be reported. In this study, we identified four novel tetranucleotide STR loci located in the X chromosome, which is the basis of X-STR research. These four tetranucleotide STRs were located within 71kb of the chromosome Xp22.3 region. Using sequence analysis of the structure of repeat sequences, we identified simple repeat sequences of TAAA, CTTT, TATC, and GATA with rare insertions. We then calculated forensic statistical parameters using base length analysis. In the Japanese population, the polymorphism information content was 0.597-0.687, power of discrimination in females was 0.829-0.884, and power of discrimination in males was 0.635-0.729. As these tetranucleotide STRs are closely linked, we conducted haplotype analysis and detected that three loci (LC149476, LC149479, and LC149480) were in linkage disequilibrium. We demonstrated that the simultaneous analysis of these loci may be useful in complex kinship cases. Because these four loci can be detected by multiplex PCR, the detection of alleles at these loci can be rapidly and easily achieved. We conclude that the X-STR loci detected in this study may be useful tools in complex kinship cases and may increase the reliability of genetic testing.

The study describes the development of a new multiplex PCR system that simultaneously amplifies 16 X chromosome short tandem repeats (X-STRs) loci in a single PCR reaction and its applicability on a sample of 200 from the Sinhalese population in Sri Lanka. 13 X-STR loci located in four clusters are selected for the assay (DXS10148-DXS10135-DXS8378, DXS7132-DXS10079-DXS10074-DXS10075, DXS6801-DXS6809-DXS6789 and DXS7424-DXS101-DXS7133). In addition, three single loci were also selected (DXS9902, HPRTB and DXS7423). Genomic DNA extracted using the Chelex-100 method was amplified with modified published primers and subjected to capillary gel electrophoresis. Complete DNA profiles were obtained with 0.20 ng 9947A DNA and the band sizes ranged between 100 and 320 bp with 10 loci having sizes below 237 bp. A total of 160 alleles were observed among the sample with 5-23 alleles for each locus. The forensic efficiency evaluation showed high values for the combined power of discrimination in males (1 in 1 × 1010) and females (1 in 1 × 1017). Combined mean exclusion chance (MEC) indices calculated for deficiency, normal trio and duo cases were equally high (> 0.99999). Application of the new multiplex system to two actual kinship cases of full sibling and deficient paternity suggested that these 16 short tandem repeat loci are highly appropriate for forensic and kinship testing among the Sinhalese population.

Background Tunisia has a complex demographic history of migrations from within Africa, Europe, and the Middle East. However, only one population study based on X-STR markers has been reported so far. Aim To investigate the genetic polymorphisms of 17 X-STRs in two Tunisian populations from the cities of Sousse and Makthar, and to reveal the genetic relationships with other reference populations. Subjects and methods A total of 194 unrelated healthy individuals were analysed for 17 X-STR markers. Results Our results indicate that DXS6809 is the most polymorphic locus, whereas DXS6807 is the least informative marker in the populations of Sousse and Makthar. In addition, forensic statistical parameters, such as the power of discrimination in males and females, as well as the mean of exclusion in duos and trios, reveal that the panel of 17 X-STRs is highly informative and useful in different forensic applications. Overall, pairwise genetic distances (Fst) and non-metric MDS plots demonstrate clustering of different populations according to their geographic locations and their historical relationships. Conclusion Overall, the study of X-STR markers of the Tunisian populations can help to promote the establishment of a forensic DNA reference database in Tunisia and provide reference for future anthropological research.

BackgroundX‐chromosome short tandem repeats (X‐STRs) with unique sex‐linkage inheritance models play a complementary role in forensic science. Guizhou is a multiethnic province located in southwest China and some genetic evidence focusing on X‐STRs for various minorities was reported. However, population data of Guizhou Tujia are scarce.MethodsA total of 507 Guizhou Tujia individuals were profiled using the AGCU X‐19 STR kit. Allele frequencies and forensic parameters were calculated. Additionally, population genetic relationships between Guizhou Tujia and other 19 populations were explored.ResultsA total of 257 alleles with the allele frequencies ranged from 0.0013 to 0.6098 were found. The combined power of discrimination in males and females and mean exclusion chances in all case scenarios were all greater than 0.99999. Population comparisons showed Guizhou Tujia had a homogeneity with all Han populations from different administrative regions, and other ethnic populations residing in Guizhou, while had obviously genetic heterogeneity with the Altaic family populations except Xibe.ConclusionNineteen X‐STRs can afford a reliable and informative database of Guizhou Tujia population for human identification and paternity testing, especially in complex biological relations. The genetic relationships of Chinese are significantly influenced by the geographic position and ethnolinguistic origin.

Currently, two of the most widely used X-chromosome STR (X-STR) multiplexes are composed by ten (GHEP-ISFG decaplex) and 12 markers (Investigator Argus X-12 Kit). The number of markers included is a drawback for complex relative testing cases, likewise the large size of some amplicons difficult their application to degraded samples. Here, we present a new multiplex of 17 X-STRs with the aim of increasing both the resolution power and forensic applicability. This newly proposed set includes the X-STRs of the GHEP-ISFG decaplex, four X-STRs from the Investigator Argus X-12 Kit, three of them also included in the decaplex, and six additional more. In order to ensure the allele designation, an allelic ladder was developed. The validation of the present multiplex was carried out according to the revised guidelines by the SWGDAM (Scientific Working Group on DNA Analysis Methods). A total of 488 unrelated individuals from four different continents were analyzed. The forensic efficiency evaluation showed high values of combined power of discrimination in males (≥0.999999996) and females (≥0.999999999999995) as well as combined paternity exclusion probabilities in trios (≥0.99999998) and duos (≥0.999996). The results presented herein have demonstrated that the new 17 X-STR set constitutes a high-resolution alternative to the current X-STR multiplexes.

To investigate the genetic polymorphisms of 19 X-STR loci in the Han population in Northern China, samples from 628 unrelated individuals (314 males and 314 females) were collected and 19 X-STR loci were amplified by AGCU X19 STR System. A total of 270 different alleles were detected in 19 X-STR loci. All loci were in Hardy − Weinberg equilibrium and there was only one pair of linkage loci (DXS10103-DXS10101). There was no significant difference in allele frequency between male and female populations. The combined power of discrimination in males was 1–1.8667 × 10−13, while the combined power of discrimination in females was 1–3.6532 × 10−22. The combined mean paternity exclusion chance (CMEC) for X-chromosomal markers in father/daughter or mother/son duos Mean paternity exclusion chance (MECDesmarais Duo) was 1–5.1109 × 10−9. Moreover, the CMEC for X-chromosomal markers in trios involving daughters (MECDesmarais) was 1–2.0292 × 10−12. The compound amplification system composed of 19 X-STR in this study showed high polymorphism in the Han population of Northern China, which had a high application value in difficult genetic relationship identification.

In the present study, the genetic variations of 17 X-STR markers (DXS8378, DXS9898, DXS7133, GATA31E08, GATA172D05, DXS6801, DXS7423, DXS6809, DXS6799, DXS7132, DXS9902, DXS6800, DXS6789, DXS10075, DXS10079, DXS6807, and DXS6803) were analyzed in 139 unrelated individuals in Nabeul, aiming to perform an X-STR database for anthropological and forensic purposes. Our results indicate that DXS6809 was the most polymorphic locus, whereas DXS6807 was the least informative marker. In addition, the obtained values for the statistical parameters of forensic interest, i.e., the power of discrimination in males (PDM) and females (PDF), as well as the mean exclusion chance in duos (MECD) and trios (MECT) have demonstrated that this panel of 17 X-STRs is highly informative and useful for forensic application and anthropological research. Additionally, pairwise genetic distances based on FST were calculated between Nabeul population and other populations extracted from the literature. Genetic distances were represented in a non-metric MDS plot and clustering of populations according to their geographic locations and their historical relationship was detected.

X-chromosomal short tandem repeats (X-STRs) are useful for the identification of absent single parents and complex blood relations. In the present study, we aimed to identify novel STR loci for use as DNA markers by conducting polymorphism and haplotype analyses. We detected three novel STR loci (LC552061, LC552062, and LC552063, with repetitive structures of (GGAA)n(GGGA)m, (CCTT)n(CCCT)m, and (ATTT)n, respectively) in the p11.4 region of the X chromosome. For these X-STRs, the polymorphism information content values ranged from 0.5766 to 0.6377 and the power of discrimination in males and females ranged from 0.6269 to 0.6844 and from 0.8105 to 0.8537, respectively. The linkage disequilibrium analysis revealed p values of < 0.0001, < 0.0001, and 0.00909 between LC552061 and LC552062, LC552061 and LC552063, and LC552062 and LC552063, respectively. Additional linkage disequilibrium analysis including seven previously analyzed loci (LC149476, LC149479, LC149480, LC149484, LC317283, LC317284, and LC317285) revealed a p value of < 0.001 among each of the five loci (LC149476, LC149479, LC149480, LC149484, and LC317283) and between LC317284 and LC317285, indicating that they were a linked group. These results indicate that, in addition to the seven previously detected loci, the three novel X-STR loci identified in the present study might be useful DNA markers for complex kinship analysis and might support the Investigator® Argus X-12 kit.

An X-chromosome pentaplex in two linkage groups: Haplotype data in Alagoas and Rio de Janeiro populations from Brazil

The admixed Brazilian population shows high levels of genetic variability, which resulted from the contribution of three main ethnicities, Amerindian, European, and African. However, due to its huge territory, admixing has been asymmetrical, i.e., the relative contribution from each ethnicity has been unequal in the five geopolitical regions of the country. The aim of this study was to describe genetic variability using a panel of short-tandem repeats on the X chromosome (X-STR) in order to perform a comprehensive evaluation of the usefulness of such markers for forensic purposes in Brazil. Twelve X-STR (DXS9895, DXS7132, DXS6800, DXS9898, DXS6789, DXS7133, GATA172D05, DXS7130, HPRTB, GATA31E08, DXS7423, and DXS10011) were chosen and tested in a sample of 2,234 individuals belonging to 16 out of the 27 Brazilian States, representing all of its five geopolitical regions. No markers showed significant deviation from the Hardy-Weinberg equilibrium, even when analyses were partitioned to represent geopolitical regions. Genetic diversity per locus ranged from 67% (DSX7133) to 95% (DXS10011), and the State of Ceará showed the highest average genetic diversity (79% for all 12 X-STR markers). Considering the Brazilian population as a whole, the power of discrimination of the 12 X-STR panel in females (PDF) was 0.999999999999994, while the power of discrimination in males (PDM) was 0.9999999969. Such high values suggest the potential of that panel to be used in forensic applications and relatedness tests among individuals. Comparisons among the Brazilian populations investigated revealed significant differences when they were compared among each other, a pattern that was maintained when additional populations from Europe and Latin America were compared to Brazilians. Our results highlight the need and usefulness of specific genetic database for forensic purposes in Brazilian populations.

Objective To learn about the genetic diversity of X-STR and to collect data of population genetics, the six X-STR loci were tested. Methods DXS6801、 DXS9902、 DXS6809、 DXS6803、 DXS6804 and DXS6799 were amplified in a single PCR reaction. PCR products were analyzed using capillary electrophoresis and ABI prism 3100 Genetic Analyzer, with GeneMapper ID 3. 1 Analysis Software. Results Allele typing with the systems was successful for all of six loci. When 202 unrelated male and 62 unrelated female individuals from Guangdong Han population were tested, 8,6, 11, 10,6 and 9 alleles were detected for DXS6801, DXS9902, DXS6809, DXS6803, DXS6804 and DXS6799, respectively. Polymorphism information content is 0. 662 3～0. 837 6. Power of discrimination in females is 0. 824 2～0. 951 1. Mean exclusion chance for X-STR in standard trios with daughters is 0. 594 9～0. 817 4. Conclusion The six loci in the multiplex system provide high polymorphism information for forensic identification and paternity testing, particularly for difficult paternity deficiency cases Key words: X-STR; Fluorescent multiplex PCR; Genetic polymorphism; Guangdong Han populationb