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The use of genetic markers, specifically Short Tandem Repeats (STRs), has been a valuable tool for identifying persons of interest. However, the ability to analyze additional markers including Single Nucleotide Polymorphisms (SNPs) and Insertion/Deletion (INDELs) polymorphisms allows laboratories to explore other investigative leads. INDELs were chosen in this study because large panels can be differentiated by size, allowing them to be genotyped by capillary electrophoresis. Moreover, these markers do not produce stutter and are smaller in size than STRs, facilitating the recovery of genetic information from degraded samples. The INDEL Ancestry Informative Markers (AIMs) in this study were selected from the 1000 Genomes Project based on a fixation index (F ST ) greater than 0.50, high allele frequency divergence, and genetic distance. A total of 25 INDEL-AIMs were optimized and validated according to SWGDAM guidelines in a five-dye multiplex. To validate the panel, genotyping was performed on 155 unrelated individuals from four ancestral groups (Caucasian, African, Hispanic, and East Asian). Bayesian clustering and principal component analysis (PCA) were performed revealing clear separation among three groups, with some observed overlap within the Hispanic group. Additionally, the PCA results were compared against a training set of 793 samples from the 1000 Genomes Project, demonstrating consistent results. Validation studies showed the assay to be reproducible, tolerant to common inhibitors, robust with challenging casework type samples, and sensitive down to 125 pg. In conclusion, our results demonstrated the robustness and effectiveness of a 25 loci INDEL system for ancestry inference of four ancestries commonly found in the United States., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Population and geographic assignment are frequently undertaken using DNA sequences on the mitochondrial genome. Assignment to broad continental populations is common, although finer resolution to subpopulations can be less accurate due to shared genetic ancestry at a local level and members of different ancestral subpopulations cohabiting the same geographic area. This study reports on the accuracy of population and subpopulation assignment by using the sequence data obtained from the 3070 mitochondrial genomes and applying the K-nearest neighbors (KNN) algorithm. These data also included training samples used for continental and population assignment comprised of 1105 Europeans (including Austria, France, Germany, Spain, and England and Caucasian countries), 374 Africans (including North and East Africa and non-specific area (Pan-Africa)), and 1591 Asians (including Japan, Philippines, and Taiwan). Subpopulations included in this study were 1153 mitochondrial DNA (mtDNA) control region sequences from 12 subpopulations in Taiwan (including Han, Hakka, Ami, Atayal, Bunun, Paiwan, Puyuma, Rukai, Saisiyat, Tsou, Tao, and Pingpu). Additionally, control region sequence data from a further 50 samples, obtained from the Sigma Company, were included after they were amplified and sequenced. These additional 50 samples acted as the "testing samples" to verify the accuracy of the population. In this study, based on genetic distances as genetic metric, we used the KNN algorithm and the K-weighted-nearest neighbors (KWNN) algorithm weighted by genetic distance to classify individuals into continental populations, and subpopulations within the same continent. Accuracy results of ethnic inferences at the level of continental populations and of subpopulations among KNN and KWNN algorithms were obtained. The training sample set achieved an overall accuracy of 99 to 82% for assignment to their continental populations with K values from 1 to 101. Population assignment for subpopulations with K assignments from 1 to 5 reached an accuracy of 77 to 54%. Four out of 12 Taiwanese populations returned an accuracy of assignment of over 60%, Ami (66%), Atayal (67%), Saisiyat (66%), and Tao (80%). For the testing sample set, results of ethnic prediction for continental populations with recommended K values as 5, 10, and 35, based on results of the training sample set, achieved overall an accuracy of 100 to 94%. This study provided an accurate method in population assignment for not only continental populations but also subpopulations, which can be useful in forensic and anthropological studies.

Direct PCR can be used to successfully generate full STR profiles from DNA present on the surface of objects. STR profiles are only of use in cases where a potential donor profile is available for comparison, and DNA is of sufficient DNA quality and quantity to generate a reliable profile. Often, no donor information is available and only trace DNA is present on items. As a result, alternative techniques are required to generate genetic data that can provide investigative leads. Massively parallel sequencing (MPS) offers the ability to detect trace levels of DNA and improve DNA analysis success from touched items. Here, we present the first application of direct PCR coupled with MPS to generate forensic intelligence SNP data from latent DNA. The panels assessed are (1) the HIrisplex System that targets 24 SNPs to simultaneously predict hair and eye, and (2) the Precision ID Ancestry Panel that targets 165 autosomal SNPs indicative of biogeographic ancestry. For each panel, we analysed 60 touched samples across five individuals and four substrates (glass slide, fuse, zip-lock bag and wire) using Ion AmpliSeq Library Preparation Kit on the automated Ion Chef System and Ion Torrent PGM. We examine the SNP recovery, concordance with reference samples and the genotype reproducibility from different substrates and donors. The results demonstrate the application of this approach for obtaining informative genetic from trace amounts of DNA.

Forensic identification tests often need recourse to markers that can successfully type highly degraded DNA, and binary single nucleotide polymorphisms (SNPs) have become the variants of choice for such analyses because of their short amplified fragment lengths. The two main drawbacks of SNPs are their reduced power of discrimination per marker compared with mainstream forensic STRs and an inability to robustly detect mixed DNA-particularly using capillary electrophoresis genotyping systems such as SNaPshot™, where the dye signals are much more imbalanced than those of STR profiles. This study compiled a compact set of multiple-allele SNPs consisting of loci that had three or four nucleotide variants at the same site in order to address the lack of mixture detection capability with binary SNP tests, as well as improving levels of polymorphism per SNP by transitioning to a maximum of six or ten genotypes per locus. We report the development and optimisation of a SNaPshot-based forensic test comprising 27 tri-allelic and 2 tetra-allelic SNPs, which we named MASTiFF: a multiple-allele SNP test for forensics. Assessments of the MASTiFF panel's levels of discrimination power in the five main population groups indicate random match probabilities ranging from 10 -15 down to 10 -20 -improving the levels possible from an equivalent number of binary SNPs. The SNaPshot test was able to detect simple mixtures successfully with more than two alleles observed in 30% of SNPs. From allele frequency data, it is estimated that more than two alleles will be present in at least one MASTiFF SNP in 99.8% of two-person mixtures, making this panel an ideal supplementary test when SNPs are chosen for the analysis of degraded forensic DNA.

HLA eplet mismatch load has been suggested as an improvement to HLA antigen mismatch determination for organ selection. Given that eplet mismatches are determined based on amino acid sequence difference among HLA alleles, and that the frequency of HLA alleles varies between racial groups, we investigated the correlation between eplet mismatch load and allograft outcomes in 110 pediatric kidney transplant recipients who received their first organ from a donor of the same race (SRT) versus a donor of a different race (DRT). Adjusted modified Poisson regression was used to assess the interaction between eplet mismatch load and race mismatch and its effect on outcome. Caucasians and living donor recipients had lower eplet mismatched loads against their donors compared with non-Caucasian and deceased donor recipients. Overall, for the entire population, the risk of de novo HLA-DSA development was significantly increased with higher eplet loads (p < 0.001). Compared with the SRT group, the DRT group had higher eplet loads when compared with their donor, for HLA class I but not HLA class II molecules; however, there was no significant difference in the incidence of de novo HLA-DSA between the 2 groups. The risk of rejection increased significantly for DRT compared with SRT, only when class I eplet load was ≥ 70 (p = 0.04). Together this data show that eplet mismatch load analysis is an effective tool for alloimmune risk assessment. If considered for donor selection, acceptable eplet mismatch loads determined from studies in homogenous populations may restrict transplantation across racially diverse donor and patient groups with no evidence of poor outcome. Therefore, an acceptable eplet mismatch load threshold must consider the heterogeneity of the transplant population.

Inferring an unknown DNA's ancestry using a set of ancestry-informative single nucleotide polymorphisms (SNPs) in forensic science is useful to provide investigative leads. This is especially true when there is no DNA database match or specified suspect. Thus, a set of SNPs with highly robust and balanced differential power is strongly demanded in forensic science. In addition, it is also necessary to build a genotyping database for estimating the ancestry of an individual or an unknown DNA. For the differentiation of Africans, Europeans, East Asians, Native Americans, and Oceanians, the Global Nano set that includes just 31 SNPs was developed by de la Puente et al. Its ability for differentiation and balance was evaluated using the genotype data of the 1000 Genomes Phase III project and the Stanford University HGDP-CEPH. Just 402 samples were genotyped and analyzed as a reference set based on statistical methods. To validate the differentiating capacity using more samples, we developed a single-tube 28-plex SNP assay in which the SNPs were chosen from the 31 allelic loci of the Global AIMs Nano set. Three tri-allelic SNPs used to differentiate mixed-source DNA contribute little to population differentiation and were excluded here. Then, 998 individuals from 21 populations were typed, and these genotypes were combined with the genotype data obtained from 1000 Genomes Phase III and the Stanford University HGDP-CEPH (3090 total samples,43 populations) to estimate the power of this multiplex assay and build a database for the further inference of an individual or an unknown DNA sample in forensic practice.

The use of DNA to determine the ancestry of an individual is becoming more and more important in the areas of forensics. Kidd et al. (Forensic Sci Int Genet 12:215-224, 2014) have been the first to identify and catalog haplotypes, termed as minihaplotypes (1-10-kilobase spans) and microhaplotypes (≤ 200 bp), with potential use in forensic analysis. In the present study, we selected 10 short ancestry informative microhaplotypes by calculating the informativeness (I n ) according to Rosenberg et al. (Am J Hum Genet 73(6):1402-1422, 2003). In total, 2504 individuals from 26 populations in 1000 Genomes Project database Phase 3 were enrolled. Among the studied microhaplotypes, eight of them are comprised of 3 SNPs while two microhaplotypes are made up of 4 SNPs. The size (molecular extent) range of 10 microhaplotypes is 5 to 48 bp with an average of 31.4 bp. The heterozygosity value ranges from 0.2235 to 0.8958 with an average of 0.6593. The average power of discrimination (PD) values is 0.7944 and ranges from 0.3786 to 0.9242. Analyses of this dataset provided clear differentiation of the populations from the Africa, East Asia, South Asia, and Europe biogeographic regions. However, individuals from American ancestry were not well separated. To conclude, our results revealed the significance of using microhaplotypes as an ancestry informative marker. The present panel could offer a valid complementary tool in forensic applications.

Massively parallel sequencing (MPS) of identity informative single-nucleotide polymorphisms (IISNPs) enables hundreds of forensically relevant markers to be analysed simultaneously. Generating DNA sequence data enables more detailed analysis including identification of sequence variations between individuals. The GeneRead DNAseq 140 IISNP MPS panel (QIAGEN) has been evaluated on both the MiSeq (Illumina) and Ion PGM™ (Applied Biosystems) MPS platforms using the GeneRead DNAseq Targeted Panels V2 library preparation workflow (QIAGEN). The aims of this study were to (1) determine if the GeneRead DNAseq panel is effective for identity testing by assessing deviation from Hardy-Weinberg (HWE) and pairwise linkage equilibrium (LE); (2) sequence samples with the GeneRead DNAseq panel on the Ion PGM™ using the QIAGEN workflow and assess specificity, sensitivity and accuracy; (3) assess the efficacy of adding biological samples directly to the GeneRead DNAseq PCR, without prior DNA extraction; and (4) assess the effect of varying coverage and allele frequency thresholds on genotype concordance. Analyses of the 140 SNPs for HWE and LE using Fisher's exact tests and the sequential Bonferroni correction revealed that one SNP was out of HWE in the Japanese population and five SNP combinations were commonly out of LE in 13 of 14 populations. The panel was sensitive down to 0.3125 ng of DNA input. A direct-to-PCR approach (without DNA extraction) produced highly concordant genotypes. The setting of appropriate allele frequency thresholds is more effective for reducing erroneous genotypes than coverage thresholds.

Purpose: Previous research has provided evidence of a hereditary predisposition for anterior cruciate ligament (ACL) injury. The purpose of this study was to evaluate the association between ancestral population genetics and risk of non-contact ACL injuries., Methods: Blood samples were collected from 177 individuals with a history of non-contact ACL injury and 556 non-injured control individuals for analysis of the genetic material through the use of a panel of 48 INDELs ancestry genetic markers from three ancestral origins., Results: Among patients with non-contact ACL injury, 82% were male and 18% were female. In the control group, 78% were male, and 22% were female. The mean age of the non-contact ACL injury group was 31.7 years (± 10.2), and the control group was 33.8 years (± 13.2). The individual genetic contribution from INDELs of each ancestral origin varied considerably: ranging between 1.5-94.8% contribution for INDELs of African origin (mean of 21.4% of INDELs); between 2 and 96.1% contribution for INDELs of European origin (mean of 66.7% of INDELs); and between 1.3-96.4% contribution for INDELs of Amerindian origin (mean of 11.7% of INDELs). When comparing paired subjects from the non-contact ACL and control groups, the genetic analysis showed that the European ancestry score was higher in the non-contact ACL group than control group (0.70 ± 0.21 vs 0.63 ± 0.22 respectively, p < 0.001), whereas African ancestry scores (ACL group 0.18 ± 0.18 vs control group 0.24 ± 0.21, p < 0.001) and Amerindian ancestry scores (ACL group 0.11 ± 0.09 vs control group 0.12 ± 0.10, n.s.) were lower among the non-contact ACL group than in controls., Conclusion: European INDELs markers were found to represent a potential genetic predisposition for non-contact ACL injuries when compared to African and Amerindian INDELs. This study has the potential to correlate a measurable and distinct genetic marker with risk of a non-contact ACL injury. Thus, it increases knowledge base and volume of molecular and genetical factors associated with this pathology. Furthermore, this study provides guidance and evidence for the development of genetic risk-screening panels for non-contact ACL injury., Level of Evidence: Level III Diagnostic Study.

AbstractThe ability to provide accurate DNA-based forensic intelligence requires analysis of multiple DNA markers to predict the biogeographical ancestry (BGA) and externally visible characteristics (EVCs) of the donor of biological evidence. Massively parallel sequencing (MPS) enables the analysis of hundreds of DNA markers in multiple samples simultaneously, increasing the value of the intelligence provided to forensic investigators while reducing the depletion of evidential material resulting from multiple analyses. The Precision ID Ancestry Panel (formerly the HID Ion AmpliSeq™ Ancestry Panel) (Thermo Fisher Scientific) (TFS)) consists of 165 autosomal SNPs selected to infer BGA. Forensic validation criteria were applied to 95 samples using this panel to assess sensitivity (1 ng-15 pg), reproducibility (inter- and intra-run variability) and effects of compromised and forensic casework type samples (artificially degraded and inhibited, mixed source and aged blood and bone samples). BGA prediction accuracy was assessed using samples from individuals who self-declared their ancestry as being from single populations of origin (n = 36) or from multiple populations of origin (n = 14). Sequencing was conducted on Ion 318™ chips (TFS) on the Ion PGM™ System (TFS). HID SNP Genotyper v4.3.1 software (TFS) was used to perform BGA predictions based on admixture proportions (continental level) and likelihood estimates (sub-population level). BGA prediction was accurate at DNA template amounts of 125pg and 30pg using 21 and 25 PCR cycles respectively. HID SNP Genotyper continental level BGA assignments were concordant with BGAs for self-declared East Asian, African, European and South Asian individuals. Compromised, mixed source and admixed samples, in addition to sub-population level prediction, requires more extensive analysis.

The GlobalFiler™ PCR Amplification Kit is a single multiplex assay that amplifies a set of 24 markers, which encompass the European Standard Set and CODIS (Combined DNA Index System) recommended composite set of loci. In addition to more loci and a 6-dye chemistry format, the Master Mix has been formulated to allow higher sample loading volume for trace DNA samples. The GlobalFiler™ Kit has been optimized to deliver high performance on casework samples, while also delivering fast thermal cycling, with an amplification time of approximately 80 min. Here, we report the results of the developmental validation study which followed the SWGDAM (Scientific Working Group on DNA Analysis Methods) guidelines and includes data for PCR-based studies, sensitivity, species specificity, stability, precision, reproducibility and repeatability, concordance, stutter, DNA mixtures, and performance on mock casework samples. The results validate the multiplex design as well as demonstrate the kit's robustness, reliability, and suitability as an assay for human identification with casework DNA samples.

The use of bi-allelic markers such as retrotransposable element insertion polymorphisms or Innuls (for insertion/null) can overcome some limitations of short tandem repeat (STR) loci in typing forensic biological evidence. This study investigated the efficiency of the InnoTyper® 21 Innul markers in an urban admixed population sample in Rio de Janeiro (n = 40) and one highly compromised sample collected as evidence by the Rio de Janeiro police. No significant departures from Hardy-Weinberg equilibrium were detected after the Bonferroni correction (α' ≈ 0.05/20, p < 0.0025), and no significant linkage disequilibrium was observed between markers. Assuming loci independence, the cumulative random match probability (RMP) was 2.3 × 10 -8 . A lower mean Fis value was obtained for this sample population compared with those of three North American populations (African-American, Southwest Hispanic, US Caucasian). Principal component analysis with the three North American populations and one from 21 East Asian population showed that African Americans segregated as an independent group while US Caucasian, Southwest Hispanic, East Asian, and Rio de Janeiro populations are in a single large heterogeneous group. Also, a full Innuls profile was produced from an evidence sample, despite the DNA being highly degraded. In conclusion, this system is a useful complement to standard STR kits.

Studies with X-STR loci show population genetic substructure, which makes necessary the characterization of such markers in the different geographical and/or ethnic populations. Therefore, this study assessed the distribution and forensic efficiency of an X-STR decaplex system in the population of the State of Mato Grosso, as well as analysed the population structure of this State based on the aforementioned system. All X-STR markers were in Hardy-Weinberg equilibrium and linkage equilibrium, and the DXS6809 was the most informative marker. The power of discrimination value in females and males was 0.99999999995 and 0.9999994, respectively. Analysis of molecular variance indicated 1.10% (p < 0.00001) of heterogeneity among Europeans, Africans, Brazilians and other Latin Americans, and in relation to such groups, the population of the State of Mato Grosso showed lower genetic variation when compared with the Brazilian group (-0.10%, p = 0.67327). The genetic distance analysis showed lower values of F ST (0.0004 ≤ F ST  ≤ 0.00331), with non-significant p value (p > 0.00024), between the populations of Mato Grosso and Mato Grosso do Sul, Paraná and the Southeast region of Brazil (except for one sample of Rio de Janeiro). F ST values with significant p values (p ≤ 0.00024) were obtained between the population of Mato Grosso and Iberian, African and some Latin American populations. The X-STR decaplex system proved to be extremely useful in the population of the State of Mato Grosso, and the data obtained does not show the need for a specific forensic database for this State in relation to the Brazilian populations compared in this study, except for population of Rio de Janeiro.

DNA can provide forensic intelligence regarding a donor's biogeographical ancestry (BGA) and other externally visible characteristics (EVCs). A number of algorithms have been proposed to assign individual human genotypes to a BGA using ancestry informative marker (AIM) panels. This study compares the BGA assignment accuracy of the population clustering program STRUCTURE and three generic classification approaches including a Bayesian algorithm, genetic distance, and multinomial logistic regression (MLR). A selection of 142 ancestry informative single nucleotide polymorphisms (SNPs) were chosen from existing marker panels (SNPforID 34-plex, Eurasiaplex, Seldin, and Kidd's AIM panels) to assess BGA classification at the continental level for Africans, Europeans, East Asians, and Amerindians. A training set of 1093 individuals with self-declared BGA from the 1000 Genomes phase 1 database was used by each classifier to predict BGA in a test set of 516 individuals from the HGDP-CEPH (Stanford) cell line panel. Tests were repeated with 0, 10, 50, 70, and 90% of the genotypes missing. Comparison of the area under the receiver operating characteristic curves (AUROCs) showed high accuracy in STRUCTURE and the generic Bayesian approach. The latter algorithm offers a computationally simpler alternative to STRUCTURE with little loss in accuracy and is suitable for phenotype prediction while STRUCTURE is not.

Ancestry inference for an individual can only be as good as the reference populations with allele frequency data on the SNPs being used. If the most relevant ancestral population(s) does not have data available for the SNPs studied, then analyses based on DNA evidence may indicate a quite distantly related population, albeit one among the more closely related of the existing reference populations. We have added reference population allele frequencies for 14 additional population samples (with >1100 individuals studied) to the 125 population samples previously published for the Kidd Lab 55 AISNP panel. Allele frequencies are now publicly available for all 55 SNPs in ALFRED and FROG-kb for a total of 139 population samples. This Kidd Lab panel of 55 ancestry informative SNPs has been incorporated in commercial kits by both ThermoFisher Scientific and Illumina for massively parallel sequencing. Researchers employing those kits will find the enhanced set of reference populations useful.

We analyzed the GlobalFiler short tandem repeat (STR) loci for 152 and 70 unrelated individuals from Angolan and Guinean immigrant populations inhabiting Southern Portugal, respectively. After Bonferroni correction, no significant deviations from the Hardy-Weinberg equilibrium and linkage disequilibrium were detected for either population. For the Angolan population, SE33 was the most informative marker. In contrast, D5S818 and D13S317 were the least informative loci. The combined power of discrimination was 99.9999999999999999999999961907%. For the Guinean population, SE33 and D21S1 were the most informative loci, while D13S317 was the least. The combined power of discrimination was 99.99999999999999999999997915%. No significant differences were observed between Angolan, Guinean, and Afro-American populations for any of the analyzed STRs. The South African population presented significant differences at D22S1045 and D10S1248 when compared to Angola, and at D22S1045 when compared to Guinea-Bissau. The MDS plot and neighbor-joining tree analysis revealed that Angolan and Guinean populations are genetically close to African-American and South African populations, and genetically different from Korean, Mexican, European (including American-Caucasian), and Middle Eastern populations.

Short tandem repeats are the gold standard for human identification but are not informative for forensic DNA phenotyping (FDP). Single-nucleotide polymorphisms (SNPs) as genetic markers can be applied to both identification and FDP. The concept of DNA intelligence emerged with the potential for SNPs to infer biogeographical ancestry (BGA) and externally visible characteristics (EVCs), which together enable the FDP process. For more than a decade, the SNaPshot ® technique has been utilised to analyse identity and FDP-associated SNPs in forensic DNA analysis. SNaPshot is a single-base extension (SBE) assay with capillary electrophoresis as its detection system. This multiplexing technique offers the advantage of easy integration into operational forensic laboratories without the requirement for any additional equipment. Further, the SNP panels from SNaPshot ® assays can be incorporated into customised panels for massively parallel sequencing (MPS). Many SNaPshot ® assays are available for identity, BGA and EVC profiling with examples including the well-known SNPforID 52-plex identity assay, the SNPforID 34-plex BGA assay and the HIrisPlex EVC assay. This review lists the major forensically relevant SNaPshot ® assays for human DNA SNP analysis and can be used as a guide for selecting the appropriate assay for specific identity and FDP applications.

Massively parallel sequencing (MPS) offers substantial improvements over current forensic DNA typing methodologies such as increased resolution, scalability, and throughput. The Ion PGM™ is a promising MPS platform for analysis of forensic biological evidence. The system employs a sequencing-by-synthesis chemistry on a semiconductor chip that measures a pH change due to the release of hydrogen ions as nucleotides are incorporated into the growing DNA strands. However, implementation of MPS into forensic laboratories requires a robust chemistry. Ion Torrent's Hi-Q™ Sequencing Chemistry was evaluated to determine if it could improve on the quality of the generated sequence data in association with selected genetic marker targets. The whole mitochondrial genome and the HID-Ion STR 10-plex panel were sequenced on the Ion PGM™ system with the Ion PGM™ Sequencing 400 Kit and the Ion PGM™ Hi-Q™ Sequencing Kit. Concordance, coverage, strand balance, noise, and deletion ratios were assessed in evaluating the performance of the Ion PGM™ Hi-Q™ Sequencing Kit. The results indicate that reliable, accurate data are generated and that sequencing through homopolymeric regions can be improved with the use of Ion Torrent's Hi-Q™ Sequencing Chemistry. Overall, the quality of the generated sequencing data supports the potential for use of the Ion PGM™ in forensic genetic laboratories.

Ancestry informative markers (AIMs) can be used to determine population affiliation of the donors of forensic samples. In order to examine ancestry evaluations of the four major populations in the USA, 23 highly informative AIMs were identified from the International HapMap project. However, the efficacy of these 23 AIMs could not be fully evaluated in silico. In this study, these 23 SNPs were multiplexed to test their actual performance in ancestry evaluations. Genotype data were obtained from 189 individuals collected from four American populations. One SNP (rs12149261) on chromosome 16 was removed from this panel because it was duplicated on chromosome 1. The resultant 22-AIMs panel was able to empirically resolve the four major populations as in the in silico study. Eight individuals were assigned to a different group than indicated on their samples. The assignments of the 22 AIMs for these samples were consistent with AIMs results from the ForenSeq(TM) panel. No departures from Hardy-Weinberg equilibrium (HWE) and linkage disequilibrium (LD) were detected for all 22 SNPs in four US populations (after removing the eight problematic samples). The principal component analysis (PCA) results indicated that 181 individuals from these populations were assigned to the expected groups. These 22 SNPs can contribute to the candidate AIMs pool for potential forensic identification purposes in major US populations.

Ancestry informative markers (AIMs) can be used to detect and adjust for population stratification and predict the ancestry of the source of an evidence sample. Autosomal single nucleotide polymorphisms (SNPs) are the best candidates for AIMs. It is essential to identify the most informative AIM SNPs across relevant populations. Several informativeness measures for ancestry estimation have been used for AIMs selection: absolute allele frequency differences (δ), F statistics (F ST), and informativeness for assignment measure (In). However, their efficacy has not been compared objectively, particularly for determining affiliations of major US populations. In this study, these three measures were directly compared for AIMs selection among four major US populations, i.e., African American, Caucasian, East Asian, and Hispanic American. The results showed that the F ST panel performed slightly better for population resolution based on principal component analysis (PCA) clustering than did the δ panel and both performed better than the In panel. Therefore, the 23 AIMs selected by the F ST measure were used to characterize the four major American populations. Genotype data of nine sample populations were used to evaluate the efficiency of the 23-AIMs panel. The results indicated that individuals could be correctly assigned to the major population categories. Our AIMs panel could contribute to the candidate pool of AIMs for potential forensic identification purposes.

The inference of biogeographical ancestry (BGA) can provide useful information for forensic investigators when there are no suspects to be compared with DNA collected at the crime scene or when no DNA database matches exist. Although public databases are increasing in size and population scope, there is a lack of information regarding genetic variation in Eurasian populations, especially in central regions such as the Middle East. Inhabitants of these regions show a high degree of genetic admixture, characterized by an allele frequency cline running from NW Europe to East Asia. Although a proper differentiation has been established between the cline extremes of western Europe and South Asia, populations geographically located in between, i.e, Middle East and Mediterranean populations, require more detailed study in order to characterize their genetic background as well as to further understand their demographic histories. To initiate these studies, three ancestry informative SNP (AI-SNP) multiplex panels: the SNPforID 34-plex, Eurasiaplex and a novel 33-plex assay were used to describe the ancestry patterns of a total of 24 populations ranging across the longitudinal axis from NW Europe to East Asia. Different ancestry inference approaches, including STRUCTURE, PCA, DAPC and Snipper Bayes analysis, were applied to determine relationships among populations. The structure results show differentiation between continental groups and a NW to SE allele frequency cline running across Eurasian populations. This study adds useful population data that could be used as reference genotypes for future ancestry investigations in forensic cases. The 33-plex assay also includes pigmentation predictive SNPs, but this study primarily focused on Eurasian population differentiation using 33-plex and its combination with the other two AI-SNP sets.

Single nucleotide polymorphism (SNP) typing offers promise to forensic genetics. Various strategies and panels for analyzing SNP markers for individual identification have been published. However, the best panels with fewer identity SNPs for all major population groups are still under discussion. This study aimed to find more autosomal SNPs with high heterozygosity for individual identification among Asian populations. Ninety-six autosomal SNPs of 502 DNA samples from unrelated individuals of five population groups (208 Taiwanese Han, 83 Filipinos, 62 Thais, 69 Indonesians, and 80 individuals with European, Near Eastern, or South Asian ancestry) were analyzed using arrays in an initial screening, and 75 SNPs (group A, 46 newly selected SNPs; groups B, 29 SNPs based on a previous SNP panel) were selected for further statistical analyses. Some SNPs with high heterozygosity from Asian populations were identified. The combined random match probability of the best 40 and 45 SNPs was between 3.16 × 10(-17) and 7.75 × 10(-17) and between 2.33 × 10(-19) and 7.00 × 10(-19), respectively, in all five populations. These loci offer comparable power to short tandem repeats (STRs) for routine forensic profiling. In this study, we demonstrated the population genetic characteristics and forensic parameters of 75 SNPs with high heterozygosity from five population groups. This SNPs panel can provide valuable genotypic information and can be helpful in forensic casework for individual identification among these populations.

A single-tube multiplex assay of a small set of ancestry-informative markers (AIMs) for effectively estimating individual ancestry and admixture is an ideal forensic tool to trace the population origin of an unknown DNA sample. We present a newly developed 27-plex single nucleotide polymorphism (SNP) panel with highly robust and balanced differential power to perfectly assign individuals to African, European, and East Asian ancestries. Evaluating 968 previously described intercontinental AIMs from three HapMap population genotyping datasets (Yoruban in Ibadan, Nigeria (YRI); Utah residents with Northern and Western European ancestry from the Centre de'Etude du Polymorphism Humain (CEPH) collection (CEU); and Han Chinese in Beijing, China (CHB)), the best set of markers was selected on the basis of Hardy-Weinberg equilibrium (p > 0.00001), population-specific allele frequency (two of three δ values >0.5), according to linkage disequilibrium (r (2) < 0.2), and capable of being multiplexed in one tube and detected by capillary electrophoresis. The 27-SNP panel was first validated by assigning the ancestry of the 11 populations in the HapMap project. Then, we tested the 27-plex SNP assay with 1164 individuals from 17 additional populations. The results demonstrated that the SNP panel was successful for ancestry inference of individuals with African, European, and East Asian ancestry. Furthermore, the system performed well when inferring the admixture of Eurasians (EUR/EAS) after analyzing admixed populations from Xinjiang (Central Asian) as follows: Tajik (68:27), Uyghur (49:46), Kirgiz (40:57), and Kazak (36:60). For individual analyses, we interpreted each sample with a three-ancestry component percentage and a population match probability sequence. This multiplex assay is a convenient and cost-effective tool to assist in criminal investigations, as well as to correct for the effects of population stratification for case-control studies.

For the correct evaluation of the weight of genetic evidence in a forensic context, databases must reflect the structure of the population, with all possible groups being represented. Countries with a recent history of admixture between strongly differentiated populations are usually highly heterogeneous and sub-structured. Bolivia is one of these countries, with a high diversity of ethnic groups and different levels of admixture (among Native Americans, Europeans and Africans) across the territory. For a better characterization of the male lineages in Bolivia, 17 Y-STR and 42 Y-SNP loci were genotyped in samples from La Paz and Chuquisaca. Only European and Native American Y-haplogroups were detected, and no sub-Saharan African chromosomes were found. Significant differences were observed between the two samples, with a higher frequency of European lineages in Chuquisaca than in La Paz. A sample belonging to haplogroup Q1a3a1a1-M19 was detected in La Paz, in a haplotype background different from those previously found in Argentina. This result supports an old M19 North-south dispersion in South America, possibly via two routes. When comparing the ancestry of each individual assessed through his Y chromosome with the one estimated using autosomal AIMs, (a) increased European ancestry in individuals with European Y chromosomes and (b) higher Native American ancestry in the carriers of Native American Y-haplogroups were observed, revealing an association between autosomal and Y-chromosomal markers. The results of this study demonstrate that a sub-structure does exist in Bolivia at both inter- and intrapopulation levels, a fact which must be taken into account in the evaluation of forensic genetic evidence.

Though allele frequency data for a variety of X chromosomal short tandem repeat (STR) markers in a range of populations have been reported, fewer studies of mutation rates in these same markers or populations are available. In order to address possible mismatches during kinship analysis due to mutation, a robust estimate of the rate of mutation must be established. Here, mutation rates in three US populations have been determined for a total of 15 markers (DXS6789, DXS9902, DXS7132, DXS7130, DXS6795, DXS10147, DXS8378, DXS7423, HPRTB, DXS101, DXS7424, GATA31E08, GATA172D05, GATA165B12, and DXS6803). Eighteen mutations over 20,625 meioses were observed, and the overall X STR mutation rate in this study was found to be 8.73 × 10(-4) (95 % CI, 5.2-13.8 × 10(-4)). A review of published mutation rate studies revealed similar findings in other global populations, and allowed the compilation of a combined dataset of 81,310 meioses which can be employed by the forensic community.

Brazilian population derives from Native Amerindians, Europeans, and Africans. Southeastern Brazil is the most populous region of the country. The present study intended to characterize the maternal genetic ancestry of 290 individuals from southeastern (Brazil) population. Thus, we made the sequencing of the three hypervariable regions (HV1, HV2, and HV3) of the mitochondrial DNA (mtDNA). The statistical analyses were made using Arlequin software, and the median-joining haplotype networks were generated using Network software. The analysis of three hypervariable regios showed 230 (79.3 %) unique haplotypes and the most common haplotype was "263G" carried by 12 (4.1 %) individuals. The strikingly high variability generated by intense gene flow is mirrored in a high sequence diversity (0.9966 ± 0.0010), and the probability of two random individuals showing identical mtDNA haplotypes were 0.0068. The analysis of haplogroup distribution revealed that 36.9 % (n = 107) presented Amerindian haplogroups, 35.2 % (n = 102) presented African haplogroups, 27.6 % (n = 80) presented European haplogroups, and one (0.3 %) individual presented East Asian haplogroup, evidencing that the southeastern population is extremely heterogeneous and the coexistence of matrilineal lineages with three different phylogeographic origins. The genetic diversity found in the mtDNA control region in the southeastern Brazilian population reinforces the importance of increased national database in order to be important and informative in forensic cases.

DNA-based prediction for externally visible characteristics such as eye color is already a useful tool in forensic criminal investigations. The IrisPlex system, consisting of six single nucleotide polymorphisms (SNPs) and a prediction model, was developed based on individuals from several European populations. Other recent studies have developed a different prediction model, also based on European populations. In this study, we compared two prediction models using the data for the six IrisPlex SNPs genotyped on 905 individuals from 12 different Eurasian populations. All SNPs showed significant differences in allele frequencies among three groups of populations: European, genetically intermediate (Khanty, Uygur, and Yakut), and East Asian. The two prediction models, the FROG-kb calculation based on the formula of Walsh et al. (2011) and the Snipper calculation from Ruiz et al. (2013), gave identical predictions of brown eye color for the four East Asian populations with complete data but did not give concordant predictions for many individuals in the seven intermediate and European populations. Inconsistencies were mainly conclusive prediction by one model but not the other. Of the 714 individuals with complete 6-locus genotypes, the two models gave 22 % inconsistent predictions. Eliminating the 306 individuals in the Korean and three Chinese populations, in which the predictions were always consistent for brown eye color, the inconsistencies (among the remaining 408 individuals) were 38.7 %. We conclude that more attention should be paid to predictive uncertainty/error. Implementation of both prediction models in future forensic casework is one immediate way to highlight uncertainty.

Allele frequencies for 26 short tandem repeats (STRs) were obtained from a sample of 203 unrelated individuals living in the area of Florence, Prato and Pistoia (Tuscany, Central Italy). These 26 loci are in addition to the existing 13 U.S. core loci and can help provide assistance in complex kinship testing when, for example, the alleged father is not available for testing. The results were compared with U.S. Caucasian, African American and Hispanic populations.

Supplementary short tandem repeats (STRs) can be added to forensic DNA analyses when core markers fail to provide sufficient discrimination power in identity and relationship testing. We combined D6S1043 and Penta B with Promega's PowerPlex CS7 supplementary STR kit, comprising Pentas D and E plus LPL, F13A01, FES/FPS, F13B, and Penta C. The nine STRs were typed in 941 individuals from 51 diverse populations of the CEPH Human Genome Diversity Panel (HGDP-CEPH), and we report allele frequency estimates plus rare alleles identified. Both Penta B and D6S1043 show highly informative variation in all populations, exceeding most CS7 STRs and raising cumulative random match probabilities by at least two orders of magnitude. However, Penta B genotype distributions show an excess of homozygotes across all HGDP-CEPH population groups indicating likely allele dropout from uncharted SNP or Indel variation at the primer sites chosen to type this STR. The first sequence analysis of common regular and rare intermediate D6S1043 alleles is reported. D6S1043 .3 intermediate alleles were found to occur at a high frequency in Native Americans, providing scope for differentiation of this group.

The requirements in the new German guidelines for paternity analysis have not only changed according to the so-called Gendiagnostikgesetz, the new German law regulating human genetic as well as paternity analyses, but also regarding the minimal number of short tandem repeats (STRs) which should be investigated (15 STRs) and the minimal required average exclusion chance (99.999 %). Even in paternity analyses involving only two people (e.g., father and child or mother and child), this exclusion chance is mandatory. A retrospective analysis of 330 father-child cases from our routine investigations showed in 142 cases (43 %) an individual exclusion chance below 99.999 % when using 15 STRs as required, in our routine work provided by the Powerplex® 16 kit which is reported to have an average exclusion chance of 99.988 %. Therefore, these same 330 father-child pairs were additionally analysed using the Powerplex® 21 kit and 120 of these duos were additionally analysed using the Powerplex® ESX17 kit enabling the analysis of 20 or 16 loci respectively. Now, an individual exclusion chance of more than 99.999 % could be achieved in 95.5 % (Powerplex® 21; calculation without the results of D6S1043), 98.8 % (Powerplex® 21; calculation with the results of D6S1043, using allele frequencies established in this study for a German and a West African population) and 98.3 % (Powerplex® ESX17). These data clearly demonstrate that in duo cases, more than the required 15 STR loci have to be investigated to obtain sufficient results.

The characterization of externally visible traits by DNA analysis is already an important tool when investigating ancient skeletal remains and may gain similar importance in future forensic DNA analysis. This, however, depends on the different legal regulations in the different countries. Besides eye or hair color, the population origin can provide crucial information in criminal prosecution. In this study, we present the analysis of 16 single-nucleotide polymorphisms (SNPs) combined to two robust SNaPshot assays with a detection threshold of 25-pg DNA. This assay was applied to 891 people from seven different populations (West Africa, North Africa, Turkey, Near East, Balkan states, North Europe, and Japan) with a thorough statistical evaluation. The prediction model was validated by an additional 125 individuals predominantly with an ancestry from those same regions. The specificity of these SNPs for the prediction of all population origins is very high (>90 %), but the sensitivity varied greatly (more than 90 % for West Africa, but only 25 % for the Near East). We could identify West Africans with a certainty of 100 %, and people from North Africa, the Balkan states, or North Europe nearly with the same reliability while determination of Turks or people from the Near East was rather difficult. In conclusion, the two SNaPshot assays are a powerful and reliable tool for the identification of people with an ancestry in one of the above listed populations, even from degraded DNA.

Insertion-deletion polymorphisms (INDELs) are diallelic markers derived from a single mutation event. Their low mutation frequency makes them suitable for forensic and parentage testing. The examination of INDELs thus combines advantages of both short tandem repeats (STR) and single nucleotide polymorphisms (SNP). This type of polymorphisms may be examined using as small amplicon size as SNP (about 100 bp) but could be analyzed by techniques used for routine STR analysis. For our population study, we genotyped 55 unrelated Czech individuals. We also genotyped 11 trios to analyze DIPplex Kit (QIAGEN, Germany) suitability for parentage testing. DIPplex Kit contains 30 diallelic autosomal markers. INDELs in DIPplex Kit were tested with linkage disequilibrium test, which showed that they could be treated as independent markers. All 30 loci fulfill Hardy-Weinberg equilibrium. There were several significant differences between Czech and African populations, but no significant ones within European population. Probability of a match in the Czech population was 1 in 6.8 × 10(12); combined power of discrimination was 99.9999999999%. Average paternity index was 1.13-1.77 for each locus; combined paternity index reached about 27,000 for a set of 30 loci. We can conclude that DIPplex kit is useful as an additional panel of markers in paternity cases when mutations in STR polymorphisms are present. For application on degraded or inhibited samples, further optimization of buffer and primer concentrations is needed.

Insertion-deletion (INDEL) markers are very frequent in the human genome and present several advantages for population and forensic studies, such as low mutation rates, easy interpretation, small amplicons, easy genotyping, and the possibility of using multiplex PCR. The great adaptability of INDELs for amplification of low copy number or degraded DNA allows its using as an interesting platform of genetic identity by DNA in forensic cases. In the present study, we tested the ability of 48 diallelic INDEL markers on genotyping forensic samples collected from different biological samples related to criminal cases. Moreover, we evaluated the lowest DNA concentration with which there was amplification of all markers from each one of three indel-plex panels. When comparing the performances obtained by the indel-plex panels described in this study with results obtained using Identifiler® kit (Applied Biosystems) related to forensic samples, as well as to control samples with different concentrations of DNA, we observed superior efficiency on samples with low copy number or in the presence of inhibitors.

Marker sets that are based on small insertion/deletion (INDEL) alleles can serve as useful supplementary or stand-alone assays for human identification. A validation study has been performed on a human identification assay based on a panel of 30 INDELs and amelogenin using the Investigator DIPplex® kit (Qiagen). The assay was able to type DNA from a number of forensically relevant sample types and obtain full profiles with 62 pg of template DNA and partial profiles with as little as 16 pg of template DNA. The assay is reproducible, precise, and non-overlapping alleles from minor contributors were detectable in mixture analysis ranging from 6:1 to 19:1 mixtures. Population studies were performed on the 30 indels, and there were no significant departures from Hardy-Weinberg equilibrium or significant linkage disequilibrium between the markers (after correction for sampling). In all populations, the random match probability was 1.43 × 10(-11) or less, and the power of exclusion was greater than .999999999. We also discovered several microvariant alleles in our population samples. The data support that the Investigator DIPplex® kit provides a powerful supplement or stand-alone capability for human identity testing.

In this study, a short tandem repeat (STR) polymorphism in intron 7 of the human complement factor I (CFI) gene was studied in 637 DNA samples obtained from African, German, Thai, and Japanese populations and German and Japanese families. A total of 41 alleles were observed and classified into two groups, L and H, based on size differences. Group H, which consisted of 16 alleles, was observed only in Thai and Japanese populations at frequencies of 0.162 and 0.116, respectively, and was strongly associated with c.1217A in exon 11 (CFI*Ah). The heterozygosity values ranged from 0.89 in German to 0.93 in Thai populations. This STR would be a useful supplementary marker for forensic individualization.

The AmpFlSTR® NGM™ PCR Amplification Kit enables amplification of 15 autosomal short tandem repeat (STR) loci. The loci are the ten STRs in the SGM Plus® Kit plus the EDNAP and ENSFI recommended STRs D10S1248, D22S1045, D2S441, D1S1656, and D12S391. Allele frequency and other forensically relevant statistics data were generated for the NGM loci in three US population groups (African Americans, Caucasians, and Hispanics). The analyses support that the NGM multiplex is one of the most informative STR multiplex kits available to the forensic science community. At the population level, there are no more detectable departures from expectations of the independence of alleles within as well as between loci than would be expected due to chance, even for the two syntenic loci vWA and D12S391; however, linkage analysis in three large pedigree families shows close linkage between these two loci with a recombination fraction of 0.108. Therefore, in contrast to the practices in calculating the rarity of a DNA profile, for kinship analyses independence between the loci, vWA and D12S391 cannot be assumed.

Forensic DNA analysis is currently performed using highly discriminating short tandem repeat (STR) markers. SNPs are being investigated as adjunct tools for human identity testing because of their abundance in the human genome, utility for genotyping degraded DNA samples, and amenability to automation. While SNPs can provide an alternative approach, on a per locus basis they have a lower power of discrimination (PD) than STRs. With the discovery of block structures in the human genome, a novel set of SNP markers are available for further exploration of forensic utility. Several neighboring, tightly linked SNPs are inherited together and form a haplotype block, which as a haploblock has a higher discrimination power than the individual SNPs within the block. Candidate haplotype blocks were selected from three major populations (Caucasian, East Asian, and African) using the following parameters: maximum match probability reduction = 0.85, linkage disequilibrium (LD) r(2) ≥ 0.7, maximum F(st) = 0.06, minimum number of SNPs = 3, minimum heterozygosity = 0.2, and minimum number of haplotypes = 3. From the HapMap Phase II data, 253 haploblocks were identified on the 22 autosomal chromosomes. After removing haploblocks deviating from the Hardy-Weinberg equilibrium (HWE) or in LD with other haploblocks, 24 haploblocks remained as candidates for forensic consideration. The cumulative PD of these blocks can reach 10(-12) in the populations studied. The data support within and between haplotype independence even when they are syntenic. We propose guidelines for evidence interpretation that address the application of haplotype blocks for transfer evidence, mixture, and kinship analyses.

The state of Santa Catarina (Brazil) is known to have represented a cultural crossroads in South America due to several historic migrations mainly from Europe and Africa. We set out to scrutinize whether the genetic imprint of these migrations could be traced through analysis of the matrilineal gene pool of the Catarinenses. The entire control region of the mitochondrial DNA was studied in 80 healthy and maternally unrelated individuals. The analysis of haplogroup distribution revealed that this population is extremely heterogeneous, showing the coexistence of matrilineal lineages with three different phylogeographic origins. European lineages are the most frequent due mainly to the impact of relatively recent migratory waves from Europe. In spite of this, Native American lineages and African lineages incorporated with the slave trade are also present in noticeable proportions. The strikingly high variability generated by intense gene flow is mirrored in a high sequence diversity (0.9930) and power of discrimination (0.9806). Thus, analysis of the entire mitochondrial DNA control region emerges as a valuable tool for forensic genetic purposes in this highly admixed population, an attribute common to several present-day Latin American populations.

Single nucleotide polymorphisms (SNPs) appeal to the forensic DNA community because of their abundance in the human genome, low mutation rate, small amplicon size, and feasibility of high-throughput genotyping technologies.In an initial screening, we identified six SNP markers of sex determination by resequencing the amelogenin genes and the zinc finger protein genes located on the sex chromosomes. Furthermore, for use in human identification,we selected 30 highly polymorphic autosomal SNP markers from among a human population and examined the potential utility of these SNP markers for human identification.The combined mean match probability of 30 SNP markers was 4.83 x 10(-13). Using genotyping data from 8,842 unrelated Korean individuals, we also found that discrimination power increased 10-fold for the addition of every five SNP markers in human identification. In this study, we demonstrated that SNP markers are very useful for sex determination and human identification, even in a very homogeneous population.

Single nucleotide polymorphisms (SNPs) in the flanking regions of microsatellite loci (SNPSTRs) help to increase the power of discrimination of short tandem repeat (STR) loci. SNPs are positions in the genome that have been well-conserved over the course of evolution, so analysing them can help distinguish between STR alleles in which the number of repetitions matches due to descent from those which match by chance. This provides support for the determination of biological paternity and other kinship analyses in which mutation needs to be ruled out as grounds for exclusion. Locus D7S820 shows a variable position, SNP rs59186128, in the 5' flanking region. This study is set out (1) to determine the frequencies of SNP rs59186128 in populations with various geographical origins and (2) to estimate the possible contribution of rs59186128 to the allele discrimination of locus D7S820. To that end, individuals from European Caucasoid, Hispanic, and Afro-American populations are studied using denaturing high-performance liquid chromatography, which enables locus rs59186128 to be quickly and highly cost-effectively screened. Moreover, a method is established for determining the haplotypes of SNPSTR rs59186128&#95;D7820. The results show that SNP rs59186128 has a T allele frequency of more than 0.15 in one of the Afro-American populations studied, and the haplotype analysis shows that there is no preferential association between the alleles of SNPSTR rs59186128&#95;D7S820, which supports the idea that they could be useful in forensic applications.

Sequencing data obtained in this study provide information on the short tandem repeat allele structures of DXS9902, DXS7132, DXS6809, DXS7133, and DXS7423. Data were obtained from the three human major population groups, namely Africans, Caucasians, and Asians as well as from chimpanzees (Pan troglodytes). DXS7133 was found to be the most stable locus and DXS6809 seemed to have evolved from a simple array of CTAT units but currently reveals a highly complex and compound structure within and between humans and chimpanzees. DXS9902 results support a TAGA allele nomenclature, which increases in one repeat unit previously reported allele distributions at this locus. For DXS7132, human/chimpanzee comparisons performed in this study provided important evidence that the CTAT allele structure should be considered for allele nomenclature purposes. Also, possible population-specific intermediate type alleles (with Native American origin) were detected at this locus that could be useful for ethnic group differentiation. DXS7423 results revealed two different sequence structures and one of these structures seems to be restricted to a single allele class in just one population group (Africans).

In the present study, a multiplexed genotyping assay for ten single nucleotide polymorphisms (SNPs) located within six pigmentation candidate genes was developed on modern biological samples and applied to DNA retrieved from 25 archeological human remains from southern central Siberia dating from the Bronze and Iron Ages. SNP genotyping was successful for the majority of ancient samples and revealed that most probably had typical European pigment features, i.e., blue or green eye color, light hair color and skin type, and were likely of European individual ancestry. To our knowledge, this study reports for the first time the multiplexed typing of autosomal SNPs on aged and degraded DNA. By providing valuable information on pigment traits of an individual and allowing individual biogeographical ancestry estimation, autosomal SNP typing can improve ancient DNA studies and aid human identification in some forensic casework situations when used to complement conventional molecular markers.

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.

A new polymorphic INDEL was detected at the X-STR GATA172D05 flanking region, which corresponds to an 18-bp deletion, 141 bp upstream the TAGA repeat motif. This INDEL was found to be polymorphic in different population samples from Native Americans, Africans, and Europeans as well as in an admixed population from the Amazonia (Belém). Gene diversities varied between 37.5% in Native Americans and 49.9% in Africans. Comparison between human and chimpanzee sequences showed that the ancestral state corresponds to the presence of two copies of 18 bp, detected in both species; and the mutated allele has lost one of these two copies. The simultaneous analysis of the short tandem repeat (STR) and INDEL variation showed an association between the INDEL ancestral allele with the shorter STR alleles. High diversities were found in all population groups when combining the information provided by the INDEL and STR variation. Gene diversities varied between 76.7% in Native Americans and 80.6% in both Portugal and Belém.

An X-chromosomal multiplex amplifying ten short tandem repeats (STRs) in one single PCR reaction was developed and optimized in this work. The X-STRs included were DXS8378, DXS9898, DXS8377, HPRTB, GATA172D05, DXS7423, DXS6809, DXS7132, DXS101, and DXS6789. Decaplex performance was tested on 377 male samples from three United States population groups, namely, 130 African Americans, 104 Asians, and 143 Hispanics. DXS8377 was the most polymorphic locus across all three populations, whereas DXS7423 was the least informative marker. Genetic distance analysis (R (ST) and F (ST)) performed for the three populations residing in New York showed significant genetic distances between population groups for most pairwise comparisons, except for HPRTB, DXS6809, and DXS7132. When testing linkage disequilibrium for all pairs of loci in the three groups, no significant association was found between any pair of the loci studied, after applying Bonferroni correction. The high values for the average probability of excluding a random man obtained in all three populations when both mother and daughter are tested or when father/daughter relationships are evaluated support the potential of this decaplex system in kinship analysis. Also, the overall high power of discrimination values for samples of female and male origin, confirms the usefulness of this decaplex system in identification analysis. As expected, results also support the use of independent databases comprising these ten X-linked loci for the three US populations evaluated.

We have established 16 small multiplex reactions of two-four loci to amplify 52 recently described single-copy simple Y-STRs and typed these loci in a worldwide panel of 74 diverse men and two women. Two Y-STRs were found to be commonly multicopy in this sample set and were excluded from the study. Of the remaining 50, four (DYS481, DYS570, DYS576 and DYS643) showed higher diversities than the commonly used loci and can potentially provide increased haplotype discrimination in both forensic and anthropological work. Ten loci showed occasional missing alleles, duplicated peaks or intermediate-sized alleles.

Common variants of TCF7L2, encoding a beta-cell-expressed transcription factor, are strongly associated with increased risk of type 2 diabetes (T2D). We examined this association using both prospective and case-control designs. A total of 2,676 healthy European white middle-aged men from the prospective NPHSII (158 developed T2D over 15 years surveillance) were genotyped for two intronic SNPs [rs 7903146 (IVS3C>T) and rs12255372 (IVS4G>T)] which showed strong linkage disequilibrium (D' = 0.88, p<0.001; R(2)=0.76, p<0.001). The IVS5T allele frequency was 0.28 (95% CI 0.27-0.29) and 0.33 (0.28-0.39) in healthy and T2D, respectively (p=0.04). Compared to CC men, CT and TT men had an adjusted [for age, body mass index, systolic blood pressure, triglyceride and C-reactive protein levels] hazard ratio for T2D of 1.65 (1.13-2.41) and 1.87 (0.99-3.53), respectively, p<0.01. The population attributable fraction for diabetes risk was 17%. In 1459, European white T2D men and women (60% male), T allele frequency was 0.36 (0.34-0.38), and compared to NPHSII healthy men the OR for T2D for the CT and TT subjects was 1.43 (1.24-1.65) and 2.11 (1.69-2.63), respectively p=<0.0001. A similar effect was observed in 919 T2D Indian Asians [OR=1.50 (1.14-1.99) and 1.64 (1.03-2.63) p=0.003] and 385 Afro-Caribbean subjects [OR=1.25 (0.90-1.75) and 1.32 (0.74-2.33) p=0.17] compared to non-diabetic ethnically matched subjects from South London. Weaker associations were found for the IVS4G>T in all studies. Linkage disequilibrium between the two SNPs was high in Indian Asians (D'=0.94), but much weaker in Afro-Caribbeans (D'=0.17) and haplotype frequencies differed markedly in this group. These results extend previous observations to other ethnic groups, and strongly confirm that TCF7L2 genotype is a major risk factor for development of T2D.

Background: Our understanding of the biological basis for mucosal barrier injury (mucositis) induced by cancer therapy with radiation or drugs continues to evolve. A patient's mucosal response to cancer therapy appears to be controlled by both global (i.e. gender, underlying systemic disease, race) and tissue specific (i.e. epithelial type, intrinsic endocrine system, local microbial environment, function) factors., Conclusion: Interactions of these elements, coupled with underlying genetic influences, most likely govern the risk, course and severity of regimen-related mucosal injury.

Cuba is a multiethnic and multiracial society. Here we describe the genetic variation of a sample of the Cuban population, which include the three most common racial groups, Caucasians, Negroids and Mestizos, by means of a set of nine microsatellites (HUMTH01, HUMTPOX, HUMCFS1PO, HUMVWA, HUMFESFPS, HUMF13A, HUMF13B, HUMLPL and HUMHPRTB). The analysis presented here indicates that these STR loci are highly informative for forensic purposes. The genetic data on the major racial groups is in good agreement with current demographic tendencies and with historic events that took place during the formation of the Cuban population.