Genetic investigation of 124 SNPs in a Myanmar population using the Precision ID Identity Panel and the Illumina MiSeq

Single nucleotide polymorphisms (SNPs) have become popular in forensic genetics as an alternative to short tandem repeats (STRs). The Precision ID Identity Panel (Thermo Fisher Scientific), consisting of 90 autosomal SNPs and 34 Y-chromosomal SNPs, enabled human identification studies on global populations through next-generation sequencing (NGS). However, most previous studies on the panel have used the Ion Torrent platform, and there are few reports on the Southeast Asian population. Here, a total of 96 unrelated males from Myanmar (Yangon) were analyzed with the Precision ID Identity Panel on a MiSeq (Illumina) using an in-house TruSeq compatible universal adapter and a custom variant caller, Visual SNP. The sequencing performance evaluated by locus balance and heterozygote balance was comparable to that of the Ion Torrent platform. For 90 autosomal SNPs, the combined match probability (CMP) was 6.994 × 10⁻³⁴, lower than that of 22 PowerPlex Fusion autosomal STRs (3.130 × 10⁻²⁶). For 34 Y-SNPs, 14 Y-haplogroups (mostly O2 and O1b) were observed. We found 51 cryptic variations (42 haplotypes) around target SNPs, of which haplotypes corresponding to 33 autosomal SNPs decreased CMP. Interpopulation analysis revealed that the Myanmar population is genetically closer to the East and Southeast Asian populations. In conclusion, the Precision ID Identity Panel can be successfully analyzed on the Illumina MiSeq and provides high discrimination power for human identification in the Myanmar population. This study broadened the accessibility of the NGS-based SNP panel by expanding the available NGS platforms and adopting a robust NGS data analysis tool.     

Development of SNP-based human identification system

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 × 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.     

Development of a SNP set for human identification: A set with high powers of discrimination which yields high genetic information from naturally degraded DNA samples in the Thai population

This study describes the development of a SNP typing system for human identification in the Thai population, in particular for extremely degraded DNA samples. A highly informative SNP marker set for forensic identification was identified, and a multiplex PCR-based Invader assay was developed. Fifty-one highly informative autosomal SNP markers and three sex determination SNP markers were amplified in two multiplex PCR reactions and then detected using Invader assay reactions. The average PCR product size was 71 base pairs. The match probability of the 54-SNP marker set in 124 Thai individuals was 1.48 × 10⁻²¹, higher than that of STR typing, suggesting that this 54-SNP marker set is beneficial for forensic identification in the Thai population. The selected SNP marker set was also evaluated in 90 artificially degraded samples, and in 128 naturally degraded DNA samples from real forensic casework which had shown no profiles or incomplete profiles when examined using a commercial STR typing system. A total of 56 degraded samples (44%) achieved the matching probability (PM) equivalent to STR gold standard analysis (successful genotyping of 44 SNP markers) for human identification. These data indicated that our novel 54-SNP marker set provides a very useful and valuable approach for forensic identification in the Thai population, especially in the case of highly to extremely degraded DNA.In summary, we have developed a set of 54 Thai-specific SNPs for human identification which have higher discrimination power than STR genotyping. The PCRs for these 54 SNP markers were successfully combined into two multiplex reactions and detected with an Invader assay. This novel SNP genotyping system also yields high levels of genetic information from naturally degraded samples, even though there are much more difficult to recover than artificially degraded samples.     

Molecular characterization and forensic relevance of the autosomal STRs for the population of North Indian geographical province Himachal Pradesh,India

Keeping in view the diverse demography of India, present study was undertaken to explore the molecular characterization and forensic relevance of 20 autosomal STRs for the highly diverse population of north Indian state Himachal Pradesh. 724 unrelated individuals from the admixed population of Himachal Pradesh were undertaken for present study and 20 autosomal STRs used to explore genomic diversity of studied population. A total of 270 different alleles along with 13.5 alleles per locus were observed. The allele 8 of the locus TPOX was observed as the most frequent allele. Observed heterozygosity ranged from 0.677 to 0.898, which supported wide range of selection of the unrelated individuals for this study. Combined power of discrimination, power of exclusion, matching probability and paternity index were observed as 1, 0.9999999958, 3.9 × 10⁻²⁶ and 2.3 × 10⁸ respectively, across the studied loci. In the population differentiation test, studied population showed genetic relatedness with Indian population rather than the populations of West, North and North east countries. Present study deciphered the novel autosomal STR data, which could be useful for the forensic application and population genetic studies.     

Application of the new insertion–deletion polymorphism kit for forensic identification and parentage testing on the Czech population

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?×?10¹²; 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.     

The art of traditional native PAGE: The APLP 48-ID assay for human identification

When full STR profiles cannot be obtained, further DNA analyses targeting single nucleotide polymorphisms (SNPs) may occasionally yield valuable information. Although the discrimination power of each SNP is relatively low, combined analysis of many SNPs can improve the personal identification ability to a level as high as that of commercial STR typing kits. In this study, we developed a new SNP typing method, named the amplified-product length polymorphism (APLP) 48-ID assay, for genotyping of 47 autosomal SNPs and two X and Y chromosomal markers for sex typing. Forty-seven SNPs were selected from all 22 autosomes, showing high diversity in European, Nigerian, Han Chinese, and Japanese population in the HapMap data. PCR primers were designed to generate amplicons 40–100 bp in length to increase the robustness of the PCR.The APLP 48-ID assay consisted of four independent PCR reactions followed by electrophoretic run on four lanes in a polyacrylamide gel. Complete profiles were obtained when more than 1.2 ng of DNA was used. We applied this assay for genotyping of 236 Japanese individuals. The random matching probability was 3.3E-20, and the power of exclusion was greater than 0.9999999. This method is a rapid, robust, and cost-effective approach for human identification and paternity testing.     

Performance of the SNPforID 52 SNP-plex assay in paternity testing

The performance of a multiplex assay with 52 autosomal single nucleotide polymorphisms (SNPs) developed for human identification was tested on 124 mother–child–father trios. The typical paternity indices (PIs) were 10⁵–10⁶ for the trios and 10³–10⁴ for the child–father duos. Using the SNP profiles from the randomly selected trios and 700 previously typed individuals, a total of 83,096 comparisons between mother, child and an unrelated man were performed. On average, 9–10 mismatches per comparison were detected. Four mismatches were genetic inconsistencies and 5–6 mismatches were opposite homozygosities. In only two of the 83,096 comparisons did an unrelated man match perfectly to a mother–child duo, and in both cases the PI of the true father was much higher than the PI of the unrelated man. The trios were also typed for 15 short tandem repeats (STRs) and seven variable number of tandem repeats (VNTRs). The typical PIs based on 15 STRs or seven VNTRs were 5–50 times higher than the typical PIs based on 52 SNPs. Six mutations in tandem repeats were detected among the randomly selected trios. In contrast, there was not found any mutations in the SNP loci. The results showed that the 52 SNP-plex assay is a very useful alternative to currently used methods in relationship testing. The usefulness of SNP markers with low mutation rates in paternity and immigration casework is discussed.     

<Emphasis Type="Bold">Y-chromosome genetic structure in sub-Apennine populations of Central Italy by SNP and STR analysis</Emphasis>

To define the Y-chromosome genetic structure in Apennine populations, 17 Y-chromosome short tandem repeats (Y-STRs) and 37 Y-single nucleotide polymorphisms (Y-SNPs) were typed in 162 subjects living in the upland area of the Marches (Central Italy). A total number of 155 haplotypes (haplotype diversity was 0.9994) and 14 SNP haplogroups were observed. Testing high-resolution Y-chromosome data sets, e.g. using Yfiler and SNPs, increases the discriminatory capacity in individual identification for forensic purposes. It is also useful in autochthonous population and micro-population studies to highlight the most informative loci for evolutionary aims. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Autosomal SNPs study of a population sample from Southern Portugal and from a sample of immigrants from Guinea-Bissau residing in Portugal

In recent years, autosomal single nucleotide polymorphisms (SNPs) have been comprehensively investigated in forensic research due to their usefulness in certain circumstances in complementing short tandem repeats (STRs) analysis, or even for use on their own when analysis of STRs fails. However, as with STRs, in order to properly use SNP markers in forensic casuistic we need to understand the population and forensic parameters in question. As a result of Portugal’s colonial history during the time of empire, and the subsequent process of decolonization, some African individuals migrated to Portugal, giving rise to large African and African-descendent communities. One of these groups is the community originating from Guinea-Bissau, that in 2014, was enumerated to consist of more than 17,700 individuals with official residency status, more than the third major city of Guinea-Bissau.In order to study the population and forensic parameters mentioned above for the two populations important to our casuistic, a total of 142 unrelated individuals from the South of Portugal and 90 immigrants from Guinea-Bissau (equally non related and all residing in Portugal) were typed with SNaPshot™ assay for all 52 loci included in the SNPforID 52plex.     

Analysis of the genetic structure of the Malay population: Ancestry-informative marker SNPs in the Malay of Peninsular Malaysia

Malay, the main ethnic group in Peninsular Malaysia, is represented by various sub-ethnic groups such as Melayu Banjar, Melayu Bugis, Melayu Champa, Melayu Java, Melayu Kedah Melayu Kelantan, Melayu Minang and Melayu Patani. Using data retrieved from the MyHVP (Malaysian Human Variome Project) database, a total of 135 individuals from these sub-ethnic groups were profiled using the Affymetrix GeneChip Mapping Xba 50-K single nucleotide polymorphism (SNP) array to identify SNPs that were ancestry-informative markers (AIMs) for Malays of Peninsular Malaysia. Prior to selecting the AIMs, the genetic structure of Malays was explored with reference to 11 other populations obtained from the Pan-Asian SNP Consortium database using principal component analysis (PCA) and ADMIXTURE. Iterative pruning principal component analysis (ipPCA) was further used to identify sub-groups of Malays. Subsequently, we constructed an AIMs panel for Malays using the informativeness for assignment (I_n) of genetic markers, and the K-nearest neighbor classifier (KNN) was used to teach the classification models. A model of 250 SNPs ranked by I_n, correctly classified Malay individuals with an accuracy of up to 90%. The identified panel of SNPs could be utilized as a panel of AIMs to ascertain the specific ancestry of Malays, which may be useful in disease association studies, biomedical research or forensic investigation purposes.     

Evaluation of a SNP-STR haplotype panel for forensic genotype imputation

Short tandem repeat polymorphism (STR)-based individual identification is a popular and reliable method in many forensic applications. However, STRs still frequently fail to find any matched records. In such cases, if known STRs could provide more information, it would be very helpful to solve specific problems. Genotype imputation has long been used in the study of single nucleotide polymorphisms (SNPs) and has recently been introduced into forensic fields. The idea is that, through a reference haplotype panel containing SNPs and STRs, we can obtain unknown genetic information through genotype imputation based on known STR or SNP genotypes. Several recent studies have already demonstrated this exciting idea, and a 1000 Genomes SNP-STR haplotype panel has also been released. To further study the performance of genotype imputation in forensic fields, we collected STR, microhaplotype (MH) and SNP array genotypes from Chinese Han population individuals and then performed genotype imputation analysis based on the released reference panel. As a result, the average locus imputation accuracy was ∼83 % (or ∼70 %) when SNPs in the SNP array (or MH SNPs) were imputed from STRs, and was ∼30 % when highly polymorphic markers (STRs and MHs) were imputed from each other. When STRs were imputed from SNP array, the average locus imputation accuracy increased to ∼48 %. After analyzing the match scores between real STRs and the STRs imputed from SNPs, ∼80 % of studied STR records can be connected to corresponding SNP records, which may help for individual identification. Our results indicate that genotype imputation has great potential for forensic applications.     

Pacifiplex: an ancestry-informative SNP panel centred on Australia and the Pacific region

The analysis of human population variation is an area of considerable interest in the forensic, medical genetics and anthropological fields. Several forensic single nucleotide polymorphism (SNP) assays provide ancestry-informative genotypes in sensitive tests designed to work with limited DNA samples, including a 34-SNP multiplex differentiating African, European and East Asian ancestries. Although assays capable of differentiating Oceanian ancestry at a global scale have become available, this study describes markers compiled specifically for differentiation of Oceanian populations. A sensitive multiplex assay, termed Pacifiplex, was developed and optimized in a small-scale test applicable to forensic analyses. The Pacifiplex assay comprises 29 ancestry-informative marker SNPs (AIM-SNPs) selected to complement the 34-plex test, that in a combined set distinguish Africans, Europeans, East Asians and Oceanians. Nine Pacific region study populations were genotyped with both SNP assays, then compared to four reference population groups from the HGDP-CEPH human diversity panel. STRUCTURE analyses estimated population cluster membership proportions that aligned with the patterns of variation suggested for each study population’s currently inferred demographic histories. Aboriginal Taiwanese and Philippine samples indicated high East Asian ancestry components, Papua New Guinean and Aboriginal Australians samples were predominantly Oceanian, while other populations displayed cluster patterns explained by the distribution of divergence amongst Melanesians, Polynesians and Micronesians. Genotype data from Pacifiplex and 34-plex tests is particularly well suited to analysis of Australian Aboriginal populations and when combined with Y and mitochondrial DNA variation will provide a powerful set of markers for ancestry inference applied to modern Australian demographic profiles. On a broader geographic scale, Pacifiplex adds highly informative data for inferring the ancestry of individuals from Oceanian populations. The sensitivity of Pacifiplex enabled successful genotyping of population samples from 50-year-old serum samples obtained from several Oceanian regions that would otherwise be unlikely to produce useful population data. This indicates tests primarily developed for forensic ancestry analysis also provide an important contribution to studies of populations where useful samples are in limited supply.     

Single nucleotide polymorphism typing with massively parallel sequencing for human identification

The Ion AmpliSeq? HID single nucleotide polymorphism (SNP) panel, a primer pool of 103 autosomal SNPs and 33 Y-SNPs, was evaluated using the Ion 314? Chip on the Ion PGM? Sequencer with four DNA samples. The study focused on the sequencing of DNA at three different initial target quantities, related interpretation issues, and concordance of results with another sequencing platform, i.e., Genome Analyzer IIx. With 10 ng of template DNA, all genotypes at the 136 SNPs were detected. With 1 ng of DNA, all SNPs were detected and one SNP locus in one sample showed extreme heterozygote imbalance on allele coverage. With 100 pg of DNA, an average of 1.6 SNP loci were not detected, and an average of 4.3 SNPs showed heterozygote imbalance. The average sequence coverage was 945–600× at autosomal SNPs and 465–209× at Y-SNPs for 10 ng–100 pg of DNA. The average heterozygote allele coverage ratio was 89.6–61.8 % for 10 ng–100 pg of DNA. At 10 ng of DNA, all genotypes of the 95 SNPs shared between the two different sequencing platforms were concordant except for one SNP, rs1029047. The error was due to the misalignment of a flanking homopolymer. Overall, the data support that genotyping a large battery of SNPs is feasible with massively parallel sequencing. With barcode systems, better allele balance, and specifically designed alignment software, a more comprehensive rapid genotyping and more cost-effective results may be obtained from multiple samples in one analysis than are possible with current typing and capillary electrophoresis systems.     

Evaluation of forensic genetic efficiency parameters of 22 autosomal STR markers (PowerPlex® Fusion system) in a population sample of Arab descent from Jordan

Jordan is a country located in the Middle East, on the East Bank of the Jordan River. In this study, the PowerPlex® Fusion (PPF) system was used to determine the allele frequencies and forensic efficiency parameters of 22 autosomal STR loci. Autosomal STR information was collected from the blood samples of 500 individuals belonging to the Jordanian population of Arab descent. The PPF system (Promega Corporation) was used to amplify the 22 autosomal STRs and the amplified samples were analysed on the 3130xl Genetic Analyser using GeneMapper ID-X 1.2 software (Applied Biosystems). All the autosomal STR loci met the requirements of the Hardy-Weinberg equilibrium after Bonferroni correction. This study revealed that the most informative locus among the 22 STR loci (excluding Amelogenin and DYS39) was Penta E locus (power of discrimination (PD) = 0.99), while the least informative locus was TPOX locus (PD = 0.834). The combined matching probability (MP) of the 22 loci was 1.9 × 10^?28. These forensic genetic parameters indicated the practicality of analysing these 22 STRs in forensic DNA identification and paternity testing among individuals from the Jordanian Arab population.     

Evaluation of the Precision ID Identity Panel for the Ion Torrent™ PGM™ sequencer

In cases where only a partial or incomplete STR profile is obtained from a sample, information contained in single nucleotide polymorphisms (SNPs) can prove informative for human identification. Thermo Fisher Scientific, which developed the high throughput Ion Torrent^™ PGM^™ sequencer, released the Precision ID Identity Panel, a multiplex SNP panel for human identity. We evaluated the reproducibility and sensitivity of this multiplex, which contains primers for the amplification of 90 autosomal SNPs and 34 Y-clade SNPs. The manufacturer’s protocol was tested using five commercially available pure native DNAs and six forensic type samples at a range of DNA input amounts (0.2–1.0 ng; n, 90). In addition to analyzing the data using the manufacturer’s software, HID SNP Genotyper (v4.3.1), we also used CLC Genomics Workbench (Qiagen). Although library yields and templating of ion sphere particles (ISPs) were low, downstream sequencing was still successful. Across all samples, only 1.5% of all possible quality control (QC) flags were raised by both the plugin QC filter and CLC; 85% of those flags were raised as the SNP had a major allele frequency outside the thresholds specified by the manufacturer. For the remaining SNPs, coverage of >1500 X and >780 X was obtained for autosomal and Y-clade SNPs respectively, and 100% congruence among genotype calls from both analysis programs was observed. Our results demonstrate that it is possible to obtain reliable and reproducible genotypes using the Precision ID Identity Panel, when using low quantities (≥0.2 ng) of either pure native DNA or forensic type DNA samples.     

Genetic portrait of 23 Y-STR loci in the Naga tribes of Nagaland,India

To explore the genomic diversity and forensic characterization of Naga tribes, Nagaland, haplotypes for 23 Y-STR markers have been analyzed. In this study, 203 unrelated male individuals residing in the Northeast Indian state of Nagaland were selected. A total of 203 unique haplotypes were observed. The value of gene diversity (GD) and discrimination capacity (DC) was observed as 0.999999998927955 and 1 respectively. Forensic interest parameters viz., power of discrimination (PD), polymorphic information content (PIC), and matching probability (PM) were found to be 0.999999998695503, 0.999999976671191, and 1.3 × 10⁻⁹ respectively, for the studied population. Inter-population comparison study showed that the Naga tribes were found to have a distinct gene pool which is reflected in the neighbor-joining tree, principle coordinate analysis, and heat map. This is the first genetic study on Naga tribes based on 23 Y-STR markers. The Y chromosomal STR data will be useful for forensic DNA application and will enrich the existing Indian Y-STR database.

     

Evaluation of genetic parameters of 22 autosomal STR loci (PowerPlex® Fusion System) in a population sample from Northern Italy

The PowerPlex® Fusion System (Promega, Madison, WI) is a short tandem repeat (STR) multiplex that allows co-amplification of 22 autosomal STRs, including the CODIS core and the European Standard Set loci, plus amelogenin for gender determination and DYS391 male specific marker included in order to avoid errors in gender assignment when null Y-alleles or deletions of the Y-chromosome short arm involve the amelogenin locus. Allele frequencies and forensic efficiency parameters were estimated in a population sample of 303 unrelated healthy individuals living in Northern Italy. No significant deviations from Hardy–Weinberg expectations were observed after applying Bonferroni’s correction for multiple testing. The combined power of discrimination was 0.999999999999 and the combined power of exclusion was 0.9999956. A rare 28 allele at locus D12S391 was observed, while one tri-allelic pattern at Penta E locus was detected. Population differentiation test revealed significant genetic diversity between our population sample and other European populations considered. The results showed that the PowerPlex® Fusion System is one of the most informative kit available in forensic genetics and may prove useful in both human identification and kinship analysis.     

A single nucleotide polymorphism panel for individual identification and ancestry assignment in Caucasians and four East and Southeast Asian populations using a machine learning classifier

Single nucleotide polymorphism (SNP) profiling is an effective means of individual identification and ancestry inferences in forensic genetics. This study established a SNP panel for the simultaneous individual identification and ancestry assignment of Caucasian and four East and Southeast Asian populations. We analyzed 220 SNPs (125 autosomal, 17 X-chromosomal, 30 Y-chromosomal, and 48 mitochondrial SNPs) of the DNA samples from 563 unrelated individuals of five populations (89 Caucasian, 234 Taiwanese Han, 90 Filipino, 79 Indonesian and 71 Vietnamese) and 18 degraded DNA samples. Informativeness for assignment (In) was used to select ancestry informative SNPs (AISNPs). A machine learning classifier, support vector machine (SVM), was used for ancestry assignment. Of the 220 SNPs, 62 were individual identification SNPs (IISNPs) (51 autosomal and 11 X-chromosomal SNPs) and 191 were AISNPs (100 autosomal, 13 X-chromosomal, 30 Y-chromosomal, and 48 mitochondrial SNPs). The 51 autosomal IISNPs offered cumulative random match probabilities (cRMPs) ranging from 1.56 × 10−21 to 3.16 × 10−22 among these five populations. Using AISNPs with the SVM, the overall accuracy rate of ancestry inference achieved in the testing dataset between Caucasian, Taiwanese Han, and Filipino populations was 88.9%, whereas it was 70.0% between Caucasians and each of the four East and Southeast Asian populations. For the 18 degraded DNA samples with incomplete profiling, the accuracy rate of ancestry assignment was 94.4%. We have developed a 220-SNP panel for simultaneous individual identification and ethnic origin differentiation between Caucasian and the four East and Southeast Asian populations. This SNP panel may assist with DNA analysis of forensic casework.     

The multiethnic ancestry of Bolivians as revealed by the analysis of Y-chromosome markers

We have analyzed the specific male genetic component of 226 Bolivians recruited in five different regions (“departments”), La Paz, Cochabamba, Pando, Beni, and Santa Cruz. To evaluate the effect of geography on the distribution of genetic variability, the samples were also grouped into three main eco-geographical regions, namely, Andean, Sub-Andean, and Llanos. All the individuals were genotyped for 17 Y-STR and 32 Y-SNP markers. The average Y-chromosome Native American component in Bolivians is 28%, and it is mainly represented by haplogroup Q1a3a, while the average Y-chromosome European ancestry is 65%, and it is mainly represented by haplogroup R1b1-P25. The data indicate that there exists significant population sub-division in the country in terms of continental ancestry. Thus, the partition of ancestries in Llanos, Sub-Andean, and Andean regions is as follows (respectively): (i) Native American ancestry: 47%, 7%, and 19%, (ii) European ancestry: 46%, 86%, and 75%, and (iii) African ancestry: 7%, 7%, and 6%. The population sub-structure in the country is also well mirrored when inferred from an AMOVA analysis, indicating that among-population variance in the country reaches 9.74–11.15%. This suggests the convenience of using regional datasets for forensic applications in Bolivia, instead of using a global and single country database. By comparing the Y-chromosome patterns with those previously reported on the same individuals on autosomal SNPs and mitochondrial DNA (mtDNA), it becomes clear that Bolivians show a strong gender-bias.     

Development of a SNP-based panel for human identification for Indian populations

The widely employed short tandem repeat (STR)-based panels for forensic human identification (HID) have limitations while dealing with challenging forensic samples involving DNA degradation, resulting in dropping-out of higher molecular weight alleles/loci. To address this issue, bialleic markers like single nucleotide polymorphisms (SNPs) and insertion-deletions (indels), which can be scored even when the template DNA is heavily degraded (<100 bp), have been suggested as alternative markers for HID testing. Recent studies have highlighted their utility in forensic HID and several panels based on biallelic markers have been described for worldwide populations. However, there has been very little information about the behavior of such DNA markers in Indian populations, which is known to possess great genetic diversity. This study describes a two-step approach for designing a SNP-based panel consisting of 70 SNPs for HID testing in Indian populations. In the first step, candidate SNPs were shortlisted from public databases by screening them for several criteria including allelic distribution, genomic location, potential phenotypic expression or functionality and species specificity. The second step involved genotyping the shortlisted SNPs in various Indian populations followed by shortlisting of the best performers for identity-testing. Starting with 592,652 SNPs listed in Human660W-Quad Beadchip (Illumina Inc.), we shortlisted 275 candidate SNPs for identity-testing and genotyped them in 462 unrelated individuals from different population groups in India. Post genotyping and statistical analyses based on biogeographic regions, 206 SNPs demonstrated desired allelic distribution (Heterozygosity ≥ 0.4 and F_ST ≤ 0.02), from which 2–4 widely separated (>20 Mb apart) SNPs from each chromosome were finally selected to construct a panel of 70 SNPs. This panel on average possessed match probability 10e-29 and probability of paternity of 0.99999997, which was orders of magnitude higher than most of the currently employed STR-based chemistries and SNP-based panels that were proposed previously for HID testing. For comparison purpose, genotyping previously reported SNPs for HID in our samples led us to conclude that the panel developed in this study is much more efficient and robust and better suited for the Indian populations.