Genetic profile characterization of 10 X-STRs in four populations of the southeastern region of Brazil

Ten X-chromosomal short tandem repeats (DXS8378, DXS9902, DXS7132, DXS9898, DXS6809, DXS6789, DXS7133, GATA172D05, GATA31E08 and DXS7423) were analyzed in four populations of the southeastern region of Brazil (São Paulo, Rio de Janeiro, Vitória and Belo Horizonte). No deviations from the Hardy–Weinberg equilibrium were observed for any of the analyzed loci in the four populations. The average diversity per locus varied between 68% for DXS8378, DXS7133, and DXS7423 and 83%, for DXS6809, with Rio de Janeiro being the most diverse population. Overall power of discrimination values in females varied between 0.99999999990 and 0.99999999997 and between 0.9999991 and 0.9999995 in males. These high values show the potential of this system for forensic application and relationships' testing in the studied groups. Genetic comparisons (exact tests of population differentiation and pairwise genetic distances) revealed significant differences between Brazilian and other populations from Europe, Latin America and Africa, as well as among different Brazilian populations.     

X-STR decaplex study on the population of Czech Republic

Sample containing 234 unrelated males and 197 unrelated females from Czech Republic was genotyped using an X-STR decaplex system in the following loci: DXS6789, DXS6809, DXS7132, DXS7133, DXS7423, DXS8378, DXS9898, DXS9902, GATA172D05, and GATA31E08. The linkage disequilibrium was observed between DXS6789 and DXS6809. The combined power of discrimination was 0.9999999998 (females) and 0.999998 (males). The mean exclusion chance was 0.999995 (trios) and 0.9998 (duos). This work presents the first population data for X-STR decaplex in Central Europe.     

Hungarian population data of four X-linked markers: DXS8378, DXS7132, HPRTB,and DXS7423

DXS8378, DXS7132, HPRTB, and DXS7423 microsatellite markers located in four different X-chromosomal linkage groups were studied in the Hungarian population. After genotyping unrelated men (219) and women (165), forensic efficiency parameters showing that the four X-linked short tandem repeats are informative for forensic applications were calculated. With fragment and sequence analysis, one microvariant allele (11.2) was identified in the HPRTB locus. A deviation from the Hardy–Weinberg equilibrium could not be detected. Investigations of 96 father–child meioses revealed one mutation in the DXS7132 locus. For comparison of 22 different populations, G-tests were carried out.     

Genetic profile characterization of ten X-STRs in a sample from Paraná, Brazil

This work reports the allele frequencies for ten X-STRs (DXS8378, DXS7132, DXS9898, DXS6809, DXS9902, DXS6789, DXS7133, DXS7423, GATA172D05, GATA31E08) in a sample of 800 individuals from Paraná, Brazil. No deviations from the Hardy–Weinberg equilibrium were observed. Linkage disequilibrium analysis did not reveal association between the X-STRs. High overall power of discrimination was obtained for female and male samples, and high probability of exclusion was observed in father/mother/daughter trios and father/daughter duos. Genetic comparisons revealed significant differences between Paraná and other Brazilian populations.     

Genetic data of a Brazilian population sample (Santa Catarina) using an X-STR decaplex

The study of X-chromosomal short tandem repeats (X-STRs) can complement the analysis of autosomal and Y-STRs. A decaplex system for the X-chromosome genetic markers, DXS8378, DXS9898, DXS7133, GATA31E08, GATA172D05, DXS7423, DXS6809, DXS7132, DXS9902 and DXS6789, was used to study a population sample of Santa Catarina, Brazil. 184 individuals (72 female and 112 male samples) were typed. DNA was amplified in a multiplex reaction and the automatic detection performed using capillary electrophoresis. Allele frequencies and some forensic parameters were calculated.     

Population genetic data for 10 X-STR loci in autochthonous Basques from Navarre (Spain)

Ten X chromosome markers (DXS6789, DXS6809, DXS7132, DXS7133, DXS7423, DXS8378, DXS9898, DXS9902, GATA172D05, and GATA31E08) were analyzed in a sample of 185 unrelated autochthonous Basques from Navarre. Deviations from Hardy-Weinberg equilibrium and linkage disequilibrium between markers were not observed at any loci. Combined power of discrimination was 0.999999999 (females) and 0.999998764 (males). Mean exclusion chance was 0.99999463 (trios) and 0.999761591 (duos). Pairwise genetic distances (Fst) of X-STR frequencies indicate significant differences in the allele frequency distribution between the autochthonous Basques from Navarre and American and Iberian populations except with the Basque Country.     

Thirteen X-chromosomal short tandem repeat loci multiplex data from Taiwanese

Study results of variations in the X chromosome are useful tools in researching the genetic diversity of human populations and individual identification. We developed a 13 X chromosomal short tandem repeat (STR) multiplex system (DXS6807, DXS8378, DSX9902, DXS7132, DXS9898, DXS6809, DXS6789, DXS7424, DXS101, GATA172D05, HPRTB, DXS8377, DXS7423) amplified in one single polymerase chain reaction. DNA samples of 113 male and 108 female Taiwanese Han subjects were successfully analyzed using this 13 X-STR multiplex system. The distributions of allele frequencies were examined for independence. DXS8377, DXS101, DXS6789, and DXS6809 were found to be the most polymorphic markers in this study. High values of discrimination power and mean exclusion chance without significant evidence of association between these markers were obtained. In conclusion, this 13 X chromosomal STR multiplex system offers considerable forensic efficiency and may be useful in forensic identification casework.     

X-chromosome STR sequence variation,repeat structure,and nomenclature in humans and chimpanzees

Qualitative information on the sequence composition of the allele and locus structure of the X-STRs DXS8378, DXS9898, DXS6789, GATA31E08, and GATA172D05 was generated in this study. Sequence data were obtained from chimpanzees (Pan troglodytes) and diverse human population groups including Africans, Caucasians, Asians, African–Americans, and Hispanics. Results revealed DXS8378 as the most stable locus. On the other hand, DXS9898 and GATA172D05 showed unstable regions identified through chimpanzee–human sequence comparison. At DXS6789, intra-allelic variation was found in all human populations, i.e., alleles with same fragment sizes showed structural differences only detected by sequencing. At the GATA31E08 locus, a previously unreported variation between humans and chimpanzees was identified in an adjacent region upstream from the repeat. This resulted in the addition of two repeat units and the proposal of a new allele nomenclature at this locus. Also, the sequence analyses did not detect ethnic differences between the studied population samples that would justify the use of these markers to help identify ethnic origin in an anthropological context. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Genetic analysis of eight population groups living in Taiwan using a 13 X-chromosomal STR loci multiplex system

A 13 X-chromosomal short tandem repeat (STR) multiplex system (DXS6807, DXS8378, DSX9902, DXS7132, DXS9898, DXS6809, DXS6789, DXS7424, DXS101, GATA172D05, HPRTB, DXS8377, and DXS7423) was tested on 1,037 DNA samples from eight population groups currently living in Taiwan. Different distributions of the allelic frequencies in different populations were presented. DXS8377 and DXS101 were the two most polymorphic loci in these eight populations, whereas DXS7423 was the least informative marker in most of the populations studied. The genetic distances between the populations and the constructed phylogenetic tree revealed a long genetic distance between Asian and Caucasian populations as well as isolation of the Tao population. The phylogenetic tree grouped populations into clusters compatible with their ethnogeographic relationships. This 13 X-chromosomal short tandem repeat multiplex system offers a considerable number of polymorphic patterns in different populations. This system can be useful in forensic identification casework and ethnogeographic research.     

The Karimojong from Uganda: Genetic characterization using an X-STR decaplex system

The Karimojong, an African group from the Karamoja region of Northeast Uganda, were genetically analysed using a decaplex system for X chromosome short tandem repeats (X-STRs). A total of 255 individuals (117 males and 138 females) were genotyped for the following loci: DXS8378, DXS9898, DXS7133, GATA31E08, GATA172D05, DXS7423, DXS6809, DXS7132, DXS9902 and DXS6789. Allele frequencies and parameters for forensic evaluation were calculated for each STR. No association was found between any pairs of loci studied. DXS6789 was the most polymorphic marker in this sample, followed by DXS6809, with gene diversities of 84.79% and 83.94%, respectively. The less discriminating locus observed was DXS7133, with a gene diversity of 39.79%. High overall values of power of discrimination were obtained for female (1 in 1.8 × 10¹⁰) and male samples (1 in 1.6 × 10⁶), as well as high power of exclusion in father/mother/daughter trios (99.9997%), in father daughter duos (99.9862%) and in half sisters with same father (99.0331%). These results confirm the potential of this 10-plex in parentage testing and in human identification.     

Sixteen X-chromosomal STRs in two octaplex PCRs in Japanese population and development of 15-locus multiplex PCR system

X-chromosome short tandem repeat (STR) polymorphisms are a useful tool in the fields of human population genetics and personal identification and are indispensable in investigating complex kinship or deficiency cases in circumstances where information on mtDNA or Y-chromosome polymorphisms is unavailable. The purpose of this study was to construct a multiplex polymerase chain reaction (PCR) system capable of analyzing a large number of X-STR loci and establish a 16-X-STR database in the Japanese population We developed two octaplex X-STR systems, one including the DXS7424, GATA172D05, HPRTB, DXS8377, GATA31E08, DXS9895, DXS7423, and DXS981 loci and the other the DXS6803, DXS6789, DXS6800, DXS6809, DXS7133, DXS7132, DXS101, and DXS6807 loci, and conducted a population study in 512 Japanese individuals comprising 339 men and 173 women. A 16-locus multiplex system produced unwanted PCR products due to mixture of the DXS9895 primer with the primers of two other loci. However, a 15-locus multiplex system exclusive of the DXS9895 locus did not. The 15-locus multiplex system amplified the largest number of loci among the X-STR multiplex systems used and afforded a power of discrimination of 0.99999999999997 in women and 0.999999997 in men.     

Validation and forensic application of a new 19 X-STR loci multiplex system

The Microreader™ 19X Direct ID System was a newly developed multiplex PCR kit, which could detect 19 X-chromosomal STR loci (DXS6795, DXS9907, DXS6803, GATA172D05, DXS6807, GATA31E08, DXS7423, DXS6810, DXS101, DXS9902, DXS7133, DXS6800, DXS981, DXS10162, DXS6809, DXS10135, HPRTB, GATA165B12, DXS10079) and the sex determination locus of AMEL simultaneously. Different from other X-STR multiplex PCR kits, no linkage groups are included in this system, so the likelihood ratios could be calculated without the consideration of linkage groups. In this study, PCR conditions, sensitivity, species specificity, stability, DNA mixtures, concordance, stutter, sizing precision and population studies were conducted according to the SWGDAM developmental validation guidelines. The results indicated that this new X-STRs multiplex system was an efficient and reliable detection system, which could facilitate human kinship analysis and identification testing, as a powerful supplementary to autosomal STR kits.     

Allele frequencies for 10 X-STR loci in Nu population of Yunnan, China

More recently, forensic interest has focused on X-chromosomal markers and which are especially useful in paternity cases with daughters. Genetic polymorphism studies at 10 short tandem repeat (STR) loci on the X-chromosome (DXS6804, DXS6799, DXS8378, DXS7130, DXS7132, HPRTB, DXS7133, DXS7423, DXS101 and DXS6789) were carried out in Yunnan Nu population of China. We aimed at increase in pool of forensically relevant data for allele distribution and frequency of X-chromosomal STRs. Statistical analysis and forensic efficiency data show no deviations from Hardy-Weinberg equilibrium.     

A GEP-ISFG collaborative study on the optimization of an X-STR decaplex: data on 15 Iberian and Latin American populations

In a collaborative work carried out by the Spanish and Portuguese ISFG Working Group (GEP-ISFG), a polymerase chain reaction multiplex was optimized in order to type ten X-chromosome short tandem repeats (STRs) in a single reaction, including: DXS8378, DXS9902, DXS7132, DXS9898, DXS6809, DXS6789, DXS7133, GATA172D05, GATA31E08, and DXS7423. Using this X-decaplex, each 17 of the participating laboratories typed a population sample of approximately 200 unrelated individuals (100 males and 100 females). In this work, we report the allele frequencies for the ten X-STRs in 15 samples from Argentina (Buenos Aires, Córdoba, Río Negro, Entre Ríos, and Misiones), Brazil (São Paulo, Rio de Janeiro, Paraná, and Mato Grosso do Sul), Colombia (Antioquia), Costa Rica, Portugal (Northern and Central regions), and Spain (Galicia and Cantabria). Gene diversities were calculated for the ten markers in each population and all values were above 56%. The average diversity per locus varied between 66%, for DXS7133, and 82%, for DXS6809. For this set of STRs, a high discrimination power was obtained in all populations, both in males (≥1 in 5?×?10⁵) and females (≥1 in 3?×?10⁹), as well as high mean exclusion chance in father/daughter duos (≥99.953%) and in father/mother/daughter trios (≥99.999%). Genetic distance analysis showed no significant differences between northern and central Portugal or between the two Spanish samples from Galicia and Cantabria. Inside Brazil, significant differences were found between Rio de Janeiro and the other three populations, as well as between São Paulo and Paraná. For the five Argentinean samples, significant distances were only observed when comparing Misiones with Entre Ríos and with Río Negro, the only two samples that do not differ significantly from Costa Rica. Antioquia differed from all other samples, except the one from Río Negro.     

Allele frequencies for 11 X chromosomal short tandem repeats in a population from Turkey

X chromosomal STRs are nowadays an important part of forensic genetic analysis, especially in complex kinship cases. In this study, allele frequencies and forensic efficiency parameters of the 11 X chromosomal STRs DXS6807, DXS8378, DXS7132, DXS6800, DXS9898, DXS7424, DXS101, DXS7133, HPRTB, DXS8377 and DXS7423 in an admixed population from Turkey are presented.     

Development and characterization of a new 12-plex ChrX miniSTR system

Short tandem repeat (STR) markers are extensively used for human identification as well as paternity and forensic casework. X-chromosome STR (X-STR) markers are a powerful complementary system especially in deficiency paternity testing. This study presents the development and characterization of a new X-chromosomal short tandem repeat (STR) multiplex using short amplicon (<200 bp). A total of 366 samples from Punjabi population and 346 samples from Sindhi population were typed for 11 X-chromosomal STR markers: DXS101, DXS6789, DXS6793, DXS7132, DXS7423, DXS7424, DXS8378, DXS9902, GATA31E08, GATA172D05, and HPRTB along with sex-typing locus, amelogenin. Each marker showed a high degree of polymorphism, and the multiplex was sensitive down to 250 pg of human DNA. A total of 78 alleles were found with 5–11 alleles for each marker. The population data can be used as reference database for Sindhi and Punjabi populations.     

Analysis of 21 X-chromosomal STRs in an Algerian population sample

Twenty-one X-chromosomal short tandem repeat loci, including the six clusters of linked markers DXS10148-DXS10135-DXS8378 (Xp22), DXS7132-DXS10074-DXS10079 (Xq12), DXS6801-DXS6809-DXS6789 (Xq21), DXS7424-DXS101 (Xq22), DXS10103-HPRTB-DXS10101 (Xq26), DXS8377-DXS10146-DXS10134-DXS7423-DXS10011 (Xq28), and the loci DXS6800 and GATA172D05 were typed in a northwestern Algerian population sample (n = 210; 104 men and 106 women). Allele and haplotype frequencies were calculated. No evidence of linkage disequilibrium was observed between pairs of loci within clusters of linked markers. At locus DXS10148, sequence analysis of a subset of alleles displaying unusual amplicon length (≥ 36 repeat units) and anomalous electrophoretic mobility showed that this marker has a complex molecular structure with different repeat variants within alleles of identical amplicon size.     

Application of a novel multiplex polymerase chain reaction system for 12 X-chromosomal short tandem repeats to a Japanese population study

The analysis of X-chromosomal short tandem repeat (X-STR) polymorphisms has been the focus of attention in several researches, mainly due to its applicability in the investigation of complex kinship cases. A new 12 X-STR multiplex system (GATA172D05, DXS7423, DSX6809, DXS10134, DXS7132, DXS9902, DXS6789, DXS10074, DXS8378, DXS9898, DXS10147, and GATA31E08) was developed and applied to a Japanese population study. DNA samples from 290 males and 160 females were successfully analyzed using the 12 X-STR multiplex system. No mutation was detected in the kinship cases involving 34 family trios. The combined powers of discrimination of the 12 X-STR loci in males and females were 0.999997 and 0.9999999996, respectively. We conclude that the combined analysis of 12 X-STR loci using this single multiplex polymerase chain reaction system is a powerful tool in forensic DNA testing.     

Multiplex PCR for 18 X-chromosomal STRs in Japanese population

X-chromosomal STR (X-STR) polymorphisms are particularly useful in complex cases of kinship testing involving inheritance through female subjects. An X-chromosomal multiplex amplifying 18 STRs in one single PCR reaction was developed and optimized in this study. The multiplex system included the DXS7424, GATA172D05, HPRTB, DXS8377, GATA31E08, DXS6810, DXS7423, DXS981, DXS6795, DXS6803, DXS6789, DXS6800, DXS6809, DXS7133, DXS7132, DXS9902, DXS101 and DXS6807 loci, which are distributed over the whole X-chromosome. It was designed as a potential first option in determining recombination within the whole X chromosome in kinship testing. Allele frequencies were obtained from samples from 378 male and 175 female Japanese individuals, all unrelated. The sizes of the amplified products ranged from 82 to 297 bp. The combined power of discrimination of the 18 loci was 0.999999999999997 in females and 0.9999999992 in males. A case is presented in which this system allowed considerable efficacy in reaching a solution. The present multiplex system amplified the largest number of loci among the X-STR multiplex systems tested, indicating its potential in personal identification and determining kinship.     

Linkage and linkage disequilibrium analysis of X-STRs in Italian families

Twenty X-chromosomal short tandem repeat (STR) loci were typed in 80 families of Italian descent, composed by mother and two or more sons, for a total of 93 meiosis. The analyzed X-STR panel included six clusters of closely linked markers (each spanning<3cM): DXS10135-DXS10148-DXS8378 (Xp22); DXS7132-DXS10074-DXS10079 (Xq12); DXS6801-DXS6809-DXS6789 (Xq21); DXS7424-DXS101 (Xq22); DXS10103-HPRTB-DXS10101 (Xq26); DXS8377-DXS10134-DXS7423-DXS10146 (Xq28). Recombination fractions between pairs of markers calculated by pedigree analysis were compared with those obtained from the second-generation Rutgers combined linkage-physical map of the human genome. The observed differences confirm that recombination is not homogeneous along the X chromosome and that the conventional subdivision of X-STRs in four groups of completely unlinked markers cannot be regarded as true. Significant linkage disequilibrium was found between markers DXS6801 and DXS6809 (p=0.017). The effect on likelihood calculations of inferring haplotype frequencies from allele distributions rather than haplotype count in the relevant population was evaluated.