Forensic use of Y-chromosome DNA: a general overview

Male-specific age prediction based on Y-chromosome DNA methylation with blood using pyrosequencing

Age prediction is an important aspect of forensic science that offers valuable insight into identification. In recent years, extensive studies have been conducted on age prediction based on DNA methylation, and numerous studies have demonstrated that DNA methylation is a reliable biomarker for age prediction. However, almost all studies on age prediction based on DNA methylation have focused on age-related CpG sites in autosomes, which are concentrated on single-source DNA samples. Mixed samples, especially male-female mixed samples, are common in forensic casework. The application of Y-STRs and Y-SNPs can provide clues for the genetic typing of male individuals in male-female mixtures, but they cannot provide the age information of male individuals. Studies on Y-chromosome DNA methylation can address this issue. In this study, we identified five age-related CpG sites on the Y chromosome (Y-CpGs) and developed a male-specific age prediction model using pyrosequencing combined with a support vector machine algorithm. The mean absolute deviation of the model was 5.50 years in the training set and 6.74 years in the testing set. When we used a male blood sample to predict age, the deviation between the predicted and chronological age was 1.18 years. Then, we mixed the genomic DNA of the male and a female at ratios of 1:1, 1:5, 1:10, and 1:50, the range of deviation between the predicted and chronological age of the male in the mixture was 1.16-1.74 years. In addition, there was no significant difference between the methylation values of bloodstains and blood in the same sample, which indicates that our model is also suitable for bloodstain samples. Overall, our results show that age prediction using DNA methylation of the Y chromosome has potential applications in forensic science and can be of great help in predicting the age of males in male-female mixtures. Furthermore, this work lays the foundation for future research on age-related applications of Y-CpGs.

Deconvoluting multi-person biological mixtures and accurate characterization and identification of separated contributors using non-targeted single-cell DNA sequencing

The genetic characterization and identification of individuals who contributed to biological mixtures are complex and mostly unresolved tasks. These tasks are relevant in various fields, particularly in forensic investigations, which frequently encounters crime scene stains generated by more than one person. Currently, forensic mixture deconvolution is mostly performed subsequent to forensic DNA profiling at the level of the mixed DNA profiles, which comes with several limitations. Some previous studies attempted at separating single cells prior to forensic DNA profiling. However, these approaches are biased at selection of the cells and, due to their targeted DNA analysis on low template DNA, provide incomplete and unreliable forensic DNA profiles. We recently demonstrated the feasibility of performing mixture deconvolution prior to forensic DNA profiling through the utilization of a non-targeted single-cell transcriptome sequencing (scRNA-seq). In addition to individual-specific mixture deconvolution, this approach also allowed accurate characterisation of biological sex, biogeographic ancestry and individual identification of the separated mixture contributors. However, RNA has the forensic disadvantage of being prone to degradation, and sequencing RNA - focussing on coding regions - limits the number of single nucleotide polymorphisms (SNPs) utilized for genetic mixture deconvolution, characterization, and identification. These limitations can be overcome by performing single-cell sequencing on the level of DNA instead of RNA. Here, for the first time, we applied non-targeted single-cell DNA sequencing (scDNA-seq) by applying the scATAC-seq (Assay for Transposase-Accessible Chromatin with sequencing) technique to address the challenges of mixture deconvolution in the forensic context. We demonstrated that scATAC-seq, together with our recently developed De-goulash data analysis pipeline, is capable of deconvoluting complex blood mixtures of five individuals from both sexes with varying biogeographic ancestries. We further showed that our approach achieved correct genetic characterization of the biological sex and the biogeographic ancestry of each of the separated mixture contributors and established their identity. Furthermore, by analysing in-silico generated scATAC-seq data mixtures, we demonstrated successful individual-specific mixture deconvolution of i) highly complex mixtures of 11 individuals, ii) balanced mixtures containing as few as 20 cells (10 per each individual), and iii) imbalanced mixtures with a ratio as low as 1:80. Overall, our proof-of-principle study demonstrates the general feasibility of scDNA-seq in general, and scATAC-seq in particular, for mixture deconvolution, genetic characterization and individual identification of the separated mixture contributors. Furthermore, it shows that compared to scRNA-seq, scDNA-seq detects more SNPs from fewer cells, providing higher sensitivity, that is valuable in forensic genetics.

Development and validation of YARN: A novel SE-400 MPS kit for East Asian paternal lineage analysis

Y-chromosomal short tandem repeat polymorphisms (Y-STRs) and Y-chromosomal single nucleotide polymorphisms (Y-SNPs) are valuable genetic markers used in paternal lineage identification and population genetics. Currently, there is a lack of an effective panel that integrates Y-STRs and Y-SNPs for studying paternal lineages, particularly in East Asian populations. Hence, we developed a novel Y-chromosomal targeted panel called YARN (Y-chromosome Ancestry and Region Network) based on multiplex PCR and a single-end 400 massive parallel sequencing (MPS) strategy, consisting of 44 patrilineage Y-STRs and 260 evolutionary Y-SNPs. A total of 386 reactions were validated for the effectiveness and applicability of YARN according to SWGDAM validation guidelines, including sensitivity (with a minimum input gDNA of 0.125 ng), mixture identification (ranging from 1:1-1:10), PCR inhibitor testing (using substances such as 50 μM hematin, 100 μM hemoglobin, 100 μM humic acid, and 2.5 mM indigo dye), species specificity (successfully distinguishing humans from other animals), repeatability study (achieved 100% accuracy), and concordance study (with 99.91% accuracy for 1121 Y-STR alleles). Furthermore, we conducted a pilot study using YARN in a cohort of 484 Han Chinese males from Huaiji County, Zhaoqing City, Guangdong, China (GDZQHJ cohort). In this cohort, we identified 52 different Y-haplogroups and 73 different surnames. We found weak to moderate correlations between the Y-haplogroups, Chinese surnames, and geographical locations of the GDZQHJ cohort (with λ values ranging from 0.050 to 0.340). However, when we combined two different categories into a new independent variable, we observed stronger correlations (with λ values ranging from 0.617 to 0.754). Overall, the YARN panel, which combines Y-STR and Y-SNP genetic markers, meets forensic DNA quality assurance guidelines and holds potential for East Asian geographical origin inference and paternal lineage analysis.

Simultaneous sequencing of 102 Y-STRs on Ion Torrent ™ GeneStudio ™ S5 System

The Precision ID NGS System from Thermo Fisher Scientific is a mainstream next-generation sequencing (NGS) platform used in forensic laboratories to detect almost all commonly used forensic markers, except for Y-chromosomal short tandem repeats (Y-STRs). This study aimed to: 1) develop a Y-STR panel compatible with the automatic workflow of the NGS system using Ion AmpliSeq Technology, 2) evaluate the panel performance following the SWGDAM guidelines, and 3) explore the possibility of using a combination workflow to detect autosomal STRs and Y-STRs (AY-STR NGS workflow). The GrandFiler Y-STR Panel was successfully designed using the 'separating' and 'merging' strategies, including 102 Y-STRs and Amelogenin with an average amplicon length of 133 bp. It is a mega Y-STR multiplex system in which up to 16 samples can be sequenced simultaneously on an Ion 530 ™ Chip. Developmental validation studies of the performance of the NGS platform, species specificity, reproducibility, concordance, sensitivity, degraded samples, case-type samples, and mixtures were conducted to unequivocally determine whether the GrandFiler Y-STR Panel is suitable for real scenarios. The newly developed Y-STR panel showed compelling run metrics and NGS performance, including 92.47% bases with ≥ Q20, 91.80% effective reads, 2106 × depth of coverage (DoC), and 97.09% inter-locus balance. Additionally, it showed high specificity for human males and 99.40% methodological and bioinformatical concordance, generated complete profiles at ≥ 0.1 ng input DNA, and recovered more genetic information from severely degraded and diverse case samples. Although the outcome when used on mixtures was not as expected, more genetic information was obtained compared to that from capillary electrophoresis (CE) methods. The AY-STR NGS workflow was established by combining the GrandFiler Y-STR Panel with the Precision ID GlobalFiler ™ NGS STR Panel v2 at a 2:1 concentration ratio. The combination workflow on NGS performance, reproducibility, concordance, and sensitivity was as stable as the single Y-STR NGS workflow, providing more options for forensic scientists when dealing with different case scenarios. Overall, the GrandFiler Y-STR Panel was confirmed as the first to effectively detect a large number of Y-STR markers on the Precision ID NGS System, which is compatible with 51 Y-STRs in commercial CE kits and 51 Y-STRs in commercial NGS kits and the STRBase. The panel is as robust, reliable, and sensitive as current CE/NGS kits, and is suitable for solving real cases, especially for severely degraded samples (degradation index > 10).

Bibliometric analysis of kinship analysis from 1960 to 2023: global trends and development

Kinship analysis is a crucial aspect of forensic genetics. This study analyzed 1,222 publications on kinship analysis from 1960 to 2023 using bibliometric analysis techniques, investigating the annual publication and citation patterns, most productive countries, organizations, authors and journals, most cited documents and co-occurrence of keywords. The initial publication in this field occurred in 1960. Since 2007, there has been a significant increase in publications, with over 30 published annually except for 2010. China had the most publications (n = 213, 17.43%), followed by the United States (n = 175, 14.32%) and Germany (n = 89, 7.28%). The United States also had the highest citation count. Sichuan University in China has the largest number of published articles. The University of Leipzig and the University of Cologne in Germany exhibit the highest total citation count and average citation, respectively. Budowle B was the most prolific author and Kayser M was the most cited author. In terms of publications, Forensic Science International- Genetics, Forensic Science International, and International Journal of Legal Medicine were the most prolific journals. Among them, Forensic Science International-Genetics boasted the highest h-index, citation count, and average citation rate. The most frequently cited publication was "Van Oven M, 2009, Hum Mutat", with a total of 1,361 citations. The most frequent co-occurrence keyword included "DNA", "Loci", "Paternity testing", "Population", "Markers", and "Identification", with recent interest focusing on "Kinship analysis", "SNP" and "Inference". The current research is centered around microhaplotypes, forensic genetic genealogy, and massively parallel sequencing. The field advanced with new DNA analysis methods, tools, and genetic markers. Collaborative research among nations, organizations, and authors benefits idea exchange, problem-solving efficiency, and high-quality results.

Evolutionary profiles and complex admixture landscape in East Asia: New insights from modern and ancient Y chromosome variation perspectives

Human Y-chromosomes are characterized by nonrecombination and uniparental inheritance, carrying traces of human history evolution and admixture. Large-scale population-specific genomic sources based on advanced sequencing technologies have revolutionized our understanding of human Y chromosome diversity and its anthropological and forensic applications. Here, we reviewed and meta-analyzed the Y chromosome genetic diversity of modern and ancient people from China and summarized the patterns of founding lineages of spatiotemporally different populations associated with their origin, expansion, and admixture. We emphasized the strong association between our identified founding lineages and language-related human dispersal events correlated with the Sino-Tibetan, Altaic, and southern Chinese multiple-language families related to the Hmong-Mien, Tai-Kadai, Austronesian, and Austro-Asiatic languages. We subsequently summarize the recent advances in translational applications in forensic and anthropological science, including paternal biogeographical ancestry inference (PBGAI), surname investigation, and paternal history reconstruction. Whole-Y sequencing or high-resolution panels with high coverage of terminal Y chromosome lineages are essential for capturing the genomic diversity of ethnolinguistically diverse East Asians. Generally, we emphasized the importance of including more ethnolinguistically diverse, underrepresented modern and spatiotemporally different ancient East Asians in human genetic research for a comprehensive understanding of the paternal genetic landscape of East Asians with a detailed time series and for the reconstruction of a reference database in the PBGAI, even including new technology innovations of Telomere-to-Telomere (T2T) for new genetic variation discovery.

Opt-in or out? Public perspectives on forensic DNA kinship investigations within the Dutch-speaking community

Forensic DNA kinship investigation involves analyzing genetic relationships between individuals to offer new leads for solving (cold) cases. Familial DNA matching has become a valuable asset in criminal case investigations, especially when traditional DNA methods hit dead ends. However, concerns surrounding ethical and privacy implications raised questions about its implementation and acceptance among the general public. The present study investigated the public perspectives regarding forensic DNA kinship investigations among 1710 Dutch-speaking Belgians using an online cross-sectional survey. The questionnaire consisted of three categories, including personal information, DNA knowledge, and their opinion on several familial DNA searching and investigative genetic genealogy related questions. The participants' average DNA knowledge score was 71 %, indicating a relatively high level of understanding of DNA-related concepts. Remarkably, the study revealed that 92 % of the participants expressed willingness to cooperate as a volunteer in a forensic DNA kinship investigation, irrespective of their scientific background or educational level. Key factors influencing participation included assurance of painless sampling and robust privacy safeguards. Participants lacking familiarity with DNA hesitated more towards participating in forensic DNA analysis, referring to "the fear of the unknown". Despite ethical and privacy concerns, the highly positive attitude towards forensic DNA analysis reflects a level of empathy and willingness to contribute to the pursuit of justice. Nearly all participants (95 %) agreed to use online DNA databases for resolving violent crimes with forensic genetic genealogy, but half emphasized the need for prior informed consent, referring to the current "opt-in" system. The results underscore the need for stringent regulations and ethical oversight to ensure the responsible use of genetic data while striking a balance between public safety and the protection of individuals' privacy rights. These findings add to the growing body of evidence regarding the potential benefits of forensic DNA kinship matching as a tool in criminal investigations, suggesting its potential future utilization and legalization.

Developmental validation of a novel 8-dye fluorescent typing system with 59 Y-STRs and 3 Y-indels for forensic applications

An 8-dye fluorescence-labeling forensic Y-chromosomal short tandem repeats (Y-STRs) kit, the 62-plex Y-STR multiplex amplification system, was developed and optimized. The system was validated by testing PCR conditions, stutter ratios (SR) and peak height ratios, sensitivity, mixture samples, precision and accuracy, species-specificity, and inhibition studies according to the Scientific Working Group on DNA Analysis Methods guidelines. PCR-based studies showed that the recommended PCR conditions were optimized for this kit. In the sensitivity study, a full profile was obtained from template DNA with a quantity of u125 pg. Consistent profiles were obtained from three different laboratories. The SRs in all loci were less than 15%, and nice balance and suitable average peak height were shown. No peaks were detected in the profiles of common animal species and microorganisms. In the male-male mixture studies, all loci were observed at a ratio of 1:8, and in the male-female mixture study, all alleles could be profiled at a ratio of 1:500 if the male DNA inputs were ≥0.5 ng/µL. An inhibitor study demonstrated that the kit had varying degrees of resistance to the presence of common inhibitors. Population study demonstrated the 62-plex Y-STR Kit improved the power of discrimination in unrelated Chinese Han males (n = 192). When haplotype diversity was 1, the probability of discrimination power of the 62-plex Y-STR Kit was 0.9948, which is suitable for forensic investigations. The results show that the developed 8-dye fluorescence labeling 62 loci system is sensitive, robust, convenient, and highly informative for forensic applications.

Uncovering Forensic Evidence: A Path to Age Estimation through DNA Methylation

Age estimation is a critical aspect of reconstructing a biological profile in forensic sciences. Diverse biochemical processes have been studied in their correlation with age, and the results have driven DNA methylation to the forefront as a promising biomarker. DNA methylation, an epigenetic modification, has been extensively studied in recent years for developing age estimation models in criminalistics and forensic anthropology. Epigenetic clocks, which analyze DNA sites undergoing hypermethylation or hypomethylation as individuals age, have paved the way for improved prediction models. A wide range of biomarkers and methods for DNA methylation analysis have been proposed, achieving different accuracies across samples and cell types. This review extensively explores literature from the past 5 years, showing scientific efforts toward the ultimate goal: applying age prediction models to assist in human identification.

Haplotype diversity of 17 Y-STR in the Iranian population

The current study aimed to evaluate Y chromosome haplotypes obtained from 1353 unrelated Iranian males using the AmpFlSTRTM YfilerTM kit; 1353 out of the 1353 identified haplotypes were unique. The haplotype diversity (HD) and discriminating capacity (DC) values were 1.00000 and 0.997, respectively. Analysis of genetic distance was performed using molecular variance (AMOVA) and multidimensional scaling plots (MDS), revealing a statistically significant difference between the study population and previous data reported for other Iranian populations and other neighboring countries. The present findings are likely to be useful for forensic casework analyses and kinship investigations.

Genetic Diversity Based on Human Y Chromosome Analysis: A Bibliometric Review Between 2014 and 2023

The Y chromosome has gained significant importance in the examination of genetic studies of populations because of its non-recombinant character and its form of uniparental inheritance. This work seeks to offer a comprehensive review of the specialty literature in the field of population genetics, focusing specifically on the analysis of the human Y chromosome using a bibliometric approach and knowledge mapping. This involves establishing worldwide structural networks by identifying the primary research themes, authors, and papers that have had a significant impact on the academic community. The objective is to examine global publications by analyzing citations at both the document and country level. This will involve conducting co-citation analysis for references with a high number of citations, examining bibliographic coupling through journal analysis, analyzing the co-occurrence of keywords, and investigating collaboration between authors from a country perspective. The research papers have been extracted from the Web of Science database. The bibliometric analysis was performed using the Bibliometrix and VOSviewer software tools. The purpose of this article is to serve as a starting point for future research dedicated to the analysis of the diversity of human Y chromosome haplotypes. The objectives of the study were to identify and present the most cited publications and references with the highest number of citations, and to highlight current publications at the national level.

Y chromosome haplogroup N in a Japanese population is classified into three subclades, and two DYS385 loci, a duplicated Y-STR, are duplicated again in subclade N-M1819

DYS385 is one of the major Y chromosome short tandem repeats (Y-STRs) in forensic genetics and exists as 2 copies in the human Y chromosome palindrome P4 region. In this study, we found that some samples were estimated to have ≥ 4 copies of DYS385 in Y chromosome haplogroup N in a Japanese population. Y chromosome haplogroup N is distributed widely in eastern/central Asia, Siberia, and eastern/northern Europe, and is also observed in Japan; however, little is known about haplogroup N subclades in the Japanese population. To reveal the link between increased DYS385 copy number and haplogroup N subclades, we sequenced single nucleotide polymorphisms to classify the subclades. As a result, the Japanese Y chromosomes of haplogroup N were classified into three subclades, and an increased DYS385 copy number was specific to subclade N-M1819* (N1b2*). These results are of use in forensic DNA analysis because Y-STR copy number is important for the interpretation of Y-STR typing results of male DNA mixtures and kinship analysis. We also found that DYS458.1 microvariants (DYS458 intermediate alleles with single-nucleotide insertion) were observed only in subclade N-CTS962 (N1b1b∼) samples. Given that previous studies reported that DYS458.1 microvariants are observed in Y chromosomes of haplogroup N in other populations, DYS458.1 might be used to infer haplogroup N subclades without limitation to the Japanese population. The results of this study will be beneficial not only to forensic genetics but also to anthropological studies.

Single Nucleotide Polymorphism (SNP) and Antibody-based Cell Sorting (SNACS): A tool for demultiplexing single-cell DNA sequencing data

Motivation

Recently, single-cell DNA sequencing (scDNA-seq) and multi-modal profiling with the addition of cell-surface antibodies (scDAb-seq) have provided key insights into cancer heterogeneity. Scaling these technologies across large patient cohorts, however, is cost and time prohibitive. Multiplexing, in which cells from unique patients are pooled into a single experiment, offers a possible solution. While multiplexing methods exist for scRNAseq, accurate demultiplexing in scDNAseq remains an unmet need.

Results

Here, we introduce SNACS: Single-Nucleotide Polymorphism (SNP) and Antibody-based Cell Sorting. SNACS relies on a combination of patient-level cell-surface identifiers and natural variation in genetic polymorphisms to demultiplex scDNAseq data. We demonstrated the performance of SNACS on a dataset consisting of multi-sample experiments from patients with leukemia where we knew truth from single-sample experiments from the same patients. Using SNACS, accuracy ranged from 0.948 - 0.991 vs 0.552 - 0.934 using demultiplexing methods from the single-cell literature.

Male Pedigree Toolbox: A Versatile Software for Y-STR Data Analyses

Y-chromosomal short tandem repeats (Y-STRs) are widely used in forensic, genealogical, and population genetics. With the recent increase in the number of rapidly mutating (RM) Y-STRs, an unprecedented level of male differentiation can be achieved, widening and improving the applications of Y-STRs in various fields, including forensics. The growing complexity of Y-STR data increases the need for automated data analyses, but dedicated software tools are scarce. To address this, we present the Male Pedigree Toolbox (MPT), a software tool for the automated analysis of Y-STR data in the context of patrilineal genealogical relationships. The MPT can estimate mutation rates and male relative differentiation rates from input Y-STR pedigree data. It can aid in determining ancestral haplotypes within a pedigree and visualize the genetic variation within pedigrees in all branches of family trees. Additionally, it can provide probabilistic classifications using machine learning, helping to establish or prove the structure of the pedigree and the level of relatedness between males, even for closely related individuals with highly similar haplotypes. The tool is flexible and easy to use and can be adjusted to any set of Y-STR markers by modifying the intuitive input file formats. We introduce the MPT software tool v1.0 and make it publicly available with the goal of encouraging and supporting forensic, genealogical, and other geneticists in utilizing the full potential of Y-STRs for both research purposes and practical applications, including criminal casework.

Law enforcement use of genetic genealogy databases in criminal investigations: Nomenclature, definition and scope

Although law enforcement use of commercial genetic genealogy databases has gained prominence since the arrest of the Golden State Killer in 2018, and it has been used in hundreds of cases in the United States and more recently in Europe and Australia, it does not have a standard nomenclature and scope. We analyzed the more common terms currently being used and propose a common nomenclature: investigative forensic genetic genealogy (iFGG). We define iFGG as the use by law enforcement of genetic genealogy combined with traditional genealogy to generate suspect investigational leads from forensic samples in criminal investigations. We describe iFGG as a proper subset of forensic genetic genealogy, that is, FGG as applied by law enforcement to criminal investigations; hence, investigative FGG or iFGG. We delineate its steps, compare and contrast it with other investigative techniques involving genetic evidence, and contextualize its use within criminal investigations. This characterization is a critical input to future studies regarding the legal status of iFGG and its implications on the right to genetic privacy.

Genetic Analysis of 27 Y-STR Haplotypes in 11 Iranian Ethnic Groups

BACKGROUND

The study of Y-chromosomal variations provides valuable insights into male susceptibility in certain diseases like cardiovascular disease (CVD). In this study, we analyzed paternal lineage in different Iranian ethnic groups, not only to identify developing medical etiology, but also to pave the way for gender-specific targeted strategies and personalized medicine in medical genetic research studies.

METHODS

The diversity of eleven Iranian ethnic groups was studied using 27 Y-chromosomal short tandem repeat (Y-STR) haplotypes from Y-filer® Plus kit. Analysis of molecular variance (AMOVA) based on pair-wise RST along with multidimensional scaling (MDS) calculation and Network phylogenic analysis was employed to quantify the differences between 503 unrelated individuals from each ethnicity.

RESULTS

Results from AMOVA calculation confirmed that Gilaks and Azeris showed the largest genetic distance (RST=0.35434); however, Sistanis and Lurs had the smallest considerable genetic distance (RST=0.00483) compared to other ethnicities. Although Azeris had a considerable distance from other ethnicities, they were still close to Turkmens. MDS analysis of ethnic groups gave the indication of lack of similarity between different ethnicities. Besides, network phylogenic analysis demonstrated insignificant clustering between samples.

CONCLUSION

The AMOVA analysis results explain that the close distance of Azeris and Turkmens may be the effect of male-dominant expansions across Central Asia that contributed to historical and demographics of populations in the region. Insignificant differences in network analysis could be the consequence of high mutation events that happened in the Y-STR regions over the years. Considering the ethnic group affiliations in medical research, our results provided an understanding and characterization of Iranian male population for future medical and population genetics studies.

Genetic polymorphism of 27 Y-STR loci in Kazakh populations from Central Kazakhstan

BACKGROUND

The haplotypes from Northern, Southern, Eastern, and Western Kazakhstan, analysed for 27 Y-STR loci, have been contributed to the Y-Chromosome STR Haplotype Reference Database, while the genetic profile of Central Kazakhstan remains inadequately explored.

AIM

To investigate the genetic diversity of 27 Y-STR loci in the Kazakh populations from Central Kazakhstan.

SUBJECTS AND METHODS

A total of 112 unrelated Central Kazakh males were genotyped via the Yfiler Plus kit. Data analysis yielded haplotype and allele frequencies, and forensic parameters. Genetic distances were graphically represented by a multidimensional scaling plot, with genetic linkages further elucidated through Nei's distance dendrograms and Median-joining networks.

RESULTS

A total of 102 haplotypes were detected, of which 96 were unique. The haplotype diversity and discrimination capacity were 0.997 and 0.91, respectively. Central Kazakhstan displays a unique cluster in analyses, underscoring its distinct Y-chromosome diversity compared to other Kazakh regions. The analysis of the Naiman tribe, predominantly residing in Central, Southern and Eastern Kazakhstan, revealed three genetic clusters of distinct haplogroups associated with their clans.

CONCLUSIONS

The identified haplotypes will enhance the existing reference database for Y-chromosomal studies in Kazakhstan, offering a robust tool for future research in population genetics, forensic science and genetic genealogy.

A proof-of-principle study: The potential application of MiniHap biomarkers in ancestry inference based on the QNome nanopore sequencing

Haplotyped SNPs convey forensic-related information, and microhaplotypes (MHs), as the most representative of this kind of marker, have proved the potential value for human forensics. In recent years, nanopore sequencing technology has developed rapidly, with its outstanding ability to sequence long continuous DNA fragments and obtain phase information, making the detection of longer haplotype marker possible. In this proof-of-principle study, we proposed a new type of forensic marker, MiniHap, based on five or more SNPs within a molecular distance less than 800 bp, and investigated the haplotype data of 56 selected MiniHaps in five Chinese populations using the QNome nanopore sequencing. The sequencing performance, allele (haplotype) frequencies, forensic parameters, effective number of alleles (Ae), and informativeness (In) were subsequently calculated. In addition, we performed principal component analysis (PCA), phylogenetic tree, and structure analysis to investigate the population genetic relationships and ancestry components among the five investigated populations and 26 worldwide populations. MiniHap-04 exhibited remarkable forensic efficacy, with 148 haplotypes reported and the Ae was 66.9268. In addition, the power of discrimination (PD) was 0.9934, the probability of exclusion (PE) was 0.9898, and the In value was 0.7893. Of the 56 loci, 85.71% had PD values above 0.85, 66.07% had PE values above 0.54, 67.86% had Ae values over 7.0%, and 55.36% were with In values above 0.2 across all samples, indicating that most of the MiniHaps are suitable for individual identification, paternity testing, mixture deconvolution, and ancestry inference. Moreover, the results of PCA, phylogenetic tree and structure analysis demonstrated that this MiniHap panel had the competency in continental population ancestry inference, but the differentiation within intracontinental/linguistically restricted subpopulations was not ideal. Such findings suggested that the QNome device for MiniHap detection was feasible and this novel marker has the potential in ancestry inference. Yet, the establishment of a more comprehensive database with sufficient reference population data remains necessary to screen more suitable MiniHaps.

Review: Computational analysis of human skeletal remains in ancient DNA and forensic genetics

Degraded DNA is used to answer questions in the fields of ancient DNA (aDNA) and forensic genetics. While aDNA studies typically center around human evolution and past history, and forensic genetics is often more concerned with identifying a specific individual, scientists in both fields face similar challenges. The overlap in source material has prompted periodic discussions and studies on the advantages of collaboration between fields toward mutually beneficial methodological advancements. However, most have been centered around wet laboratory methods (sampling, DNA extraction, library preparation, etc.). In this review, we focus on the computational side of the analytical workflow. We discuss limitations and considerations to consider when working with degraded DNA. We hope this review provides a framework to researchers new to computational workflows for how to think about analyzing highly degraded DNA and prompts an increase of collaboration between the forensic genetics and aDNA fields.

Easykin: a flexible and user-friendly online tool for forensic kinship testing and missing person identification

In forensic kinship testing and missing person identification, it is a fundamental question to choose the most informative reference relatives, select appropriate genotyping systems, and evaluate the weight of evidence comprehensively. Despite that several useful tools have been developed, they have not addressed these questions satisfactorily. In this paper, we develop a flexible and user-friendly online tool, Easykin, to address the aforementioned issues. It has some promising features: (i) Pedigrees can be constructed easily and presented intuitively with just a few mouse clicks. (ii) System power can be estimated before testing based on certain set of markers and reference relatives. (iii) The pruning function of EasyKin enables users to choose appropriate subsets of available references. (iv) Parameters at a specific LR for a single case may ease evidence interpretation. (v) The user interface (UI) is an HTML-based dashboard, which is friendly to both professional and non-professional users and can be used anytime and anywhere. Here, we presented three common cases as examples to demonstrate how kinship testing and missing person identification can be improved with EasyKin. In conclusion, this tool provides a one-stop solution for forensic use, that is, instructing users to choose appropriate kits and reference relatives before testing, calculating LR in the testing, and providing parameters for data interpretation after testing. EasyKin is freely available at https://forensicsysu.shinyapps.io/EasyKin/ .

Genetic polymorphism of Y-chromosome in Kazakh populations from Southern Kazakhstan

BACKGROUND

The Kazakhs are one of the biggest Turkic-speaking ethnic groups, controlling vast swaths of land from the Altai to the Caspian Sea. In terms of area, Kazakhstan is ranked ninth in the world. Northern, Eastern, and Western Kazakhstan have already been studied in relation to genetic polymorphism 27 Y-STR. However, current information on the genetic polymorphism of the Y-chromosome of Southern Kazakhstan is limited only by 17 Y-STR and no geographical study of other regions has been studied at this variation.

RESULTS

The Kazakhstan Y-chromosome Haplotype Reference Database was expanded with 468 Kazakh males from the Zhambyl and Turkestan regions of South Kazakhstan by having their 27 Y-STR loci and 23 Y-SNP markers analyzed. Discrimination capacity (DC = 91.23%), haplotype match probability (HPM = 0.0029) and haplotype diversity (HD = 0.9992) are defined. Most of this Y-chromosome variability is attributed to haplogroups C2a1a1b1-F1756 (2.1%), C2a1a2-M48 (7.3%), C2a1a3-F1918 (33.3%) and C2b1a1a1a-M407 (6%). Median-joining network analysis was applied to understand the relationship between the haplotypes of the three regions. In three genetic layer can be described the position of the populations of the Southern region of Kazakhstan-the geographic Kazakh populations of Kazakhstan, the Kazakh tribal groups, and the people of bordering Asia.

CONCLUSION

The Kazakhstan Y-chromosome Haplotype Reference Database was formed for 27 Y-STR loci with a total sample of 1796 samples of Kazakhs from 16 regions of Kazakhstan. The variability of the Y-chromosome of the Kazakhs in a geographical context can be divided into four main clusters-south, north, east, west. At the same time, in the genetic space of tribal groups, the population of southern Kazakhs clusters with tribes from the same region, and genetic proximity is determined with the populations of the Hazaras of Afghanistan and the Mongols of China.

Genetic Polymorphism Analysis of 24 Y-STRs in a Han Chinese Population in Luzhou, Southwest China

Han is the largest of China's 56 ethnic groups and the most populous ethnic group in the world. The Luzhou region is located in southwest China, at the junction of three provinces. The unique historical factors contribute to the genetic polymorphism information. Short tandem repeats (STRs) are highly polymorphic, but the polymorphism of the Y chromosomal STRs (Y-STRs) loci in the Luzhou region is still unclear. It is of great significance to provide Y-STRs genetic data for the Han population from the Luzhou areas of southwest China. A total of 910 unrelated male individuals of the Han population from the Luzhou area were recruited, and 24 Y-STRs were analyzed. The population structure and phylogenetic relationships were compared with those of another 11 related Han populations. A total of 893 different haplotypes were achieved from 910 samples, of which 877 (98.21%) haplotypes were unique. Haplotype diversity and discrimination were 0.999956 and 0.981319, respectively. The lowest genetic diversity of DYS437 is 0.4321, and the highest genetic diversity of DYS385a/b is 0.9642. Pair-to-pair genetic distance and relative probability values indicate that Luzhou Han people are close to Sichuan Han people, Guangdong Han people, and Hunan Han people, which is consistent with geographical distribution, historical influence, and economic development. The 24 Y-STR markers of the southwest Luzhou Han population were highly polymorphic, which provided us with genetic polymorphism information and enriched the population genetic database. Therefore, it is of great value to our forensic applications and population genetics research.

Forensic biogeographical ancestry inference: recent insights and current trends

BACKGROUND

As a powerful complement to the paradigmatic DNA profiling strategy, biogeographical ancestry inference (BGAI) plays a significant part in human forensic investigation especially when a database hit or eyewitness testimony are not available. It indicates one's biogeographical profile based on known population-specific genetic variations, and thus is crucial for guiding authority investigations to find unknown individuals. Forensic biogeographical ancestry testing exploits much of the recent advances in the understanding of human genomic variation and improving of molecular biology.

OBJECTIVE

In this review, recent development of prospective ancestry informative markers (AIMs) and the statistical approaches of inferring biogeographic ancestry from AIMs are elucidated and discussed.

METHODS

We highlight the research progress of three potential AIMs (i.e., single nucleotide polymorphisms, microhaplotypes, and Y or mtDNA uniparental markers) and discuss the prospects and challenges of two methods that are commonly used in BGAI.

CONCLUSION

While BGAI for forensic purposes has been thriving in recent years, important challenges, such as ethics and responsibilities, data completeness, and ununified standards for evaluation, remain for the use of biogeographical ancestry information in human forensic investigations. To address these issues and fully realize the value of BGAI in forensic investigation, efforts should be made not only by labs/institutions around the world independently, but also by inter-lab/institution collaborations.

Short Tandem Repeat (STR) DNA Analysis for Using Coffee Cups As Forensic Medicine Evidence

Introduction Forensic science has continually evolved, with innovations in DNA analysis techniques playing a pivotal role in improving the accuracy and reliability of criminal investigations. Short tandem repeats (STRs) have been a game-changer in forensic science, offering unique genetic markers to pinpoint individual identities. This study explores the application of STR DNA analysis to an unconventional source: coffee cups. Materials and methods In a study involving 16 unrelated, healthy individuals aged 26 to 32, DNA was investigated from coffee cups and mouth cavities, comparing the results to a previous coffee cup DNA study. Buccal swabs provided reference samples, air-dried for 10 minutes, and stored at 20°C. DNA quantification revealed a significant decrease in coffee cup samples (0.015 to 0.049 ng/μL) compared to the reference, with no DNA in negative controls. Some STR loci displayed inhibition and lower heterozygosity in the research samples. Ethical approval (REC 53-592) and adherence to the Declaration of Helsinki ensured ethical standards. This research highlights potential challenges in obtaining efficient DNA profiles from various sources. Results There was a significant variation in DNA concentrations among the different cup types, with ceramic cups yielding the highest concentrations. Moreover, the DNA profiling outcomes ranged from full profiles, which allow for precise individual identification, to partial profiles, which pose challenges for conclusive matches. These findings have profound implications for forensic science. The study demonstrates the potential of coffee cups as sources of DNA evidence in criminal investigations, even if partial profiles are obtained. Such evidence can assist in suspect identification, victim profiling, and corroborating witness statements. Conclusion This study highlights the application of STR DNA analysis for coffee cups, opening new avenues for forensic investigations and highlighting the need for continued research and development in this exciting field. This observation aligns with existing research on DNA recovery from various surfaces, and further research is warranted to refine the methodology, consider usage patterns, and address ethical and legal concerns regarding the collection and use of DNA evidence from common objects.

Genetic analysis of 42 Y-STR loci in Han and Manchu populations from the three northeastern provinces in China

BACKGROUND

Y-STR polymorphisms are useful in tracing genealogy and understanding human origins and migration history. This study aimed to fill a knowledge gap in the genetic diversity, structure, and haplogroup distribution of the Han and Manchu populations from the three northeastern provinces in China (Liaoning, Jilin, and Heilongjiang).

METHODS

A total of 1,048 blood samples were collected from unrelated males residing in Dalian. Genotyping was performed using the AGCU Y37 + 5 Amplification Kit, and the genotype data were analyzed to determine allele and haplotype frequencies, genetic and haplotype diversity, discrimination capacity, and haplotype match probability. Population pairwise genetic distances (Fst) were calculated to compare the genetic relationships among Han and Manchu populations from Northeast China and other 23 populations using 27 Yfiler Plus loci set. Multi-dimensional scaling and phylogenetic analysis were employed to visualize the genetic relationships among the 27 populations. Moreover, haplogroups were predicted based on 27 Yfiler Plus loci set.

RESULTS

The Han populations from Northeast China exhibited genetic affinities with both Han populations from the Central Plain and the Sichuan Qiang population, despite considerable geographical distances. Conversely, the Manchu population displayed a relatively large genetic distance from other populations. The haplogroup analysis revealed the prevalence of haplogroups E1b1b, O1b, O2, and Q in the studied populations, with variations observed among different ethnic groups.

CONCLUSION

The study contributes to our understanding of genetic diversity and history of the Han and Manchu populations in Northeast China, the genetic relationships between populations, and the intricate processes of migration, intermarriage, and cultural integration that have shaped the region's genetic landscape.

Benchmarking of human Y-chromosomal haplogroup classifiers with whole-genome and whole-exome sequence data

In anthropological, medical, and forensic studies, the nonrecombinant region of the human Y chromosome (NRY) enables accurate reconstruction of pedigree relationships and retrieval of ancestral information. Using high-throughput sequencing (HTS) data, we present a benchmarking analysis of command-line tools for NRY haplogroup classification. The evaluation was performed using paired Illumina data from whole-genome sequencing (WGS) and whole-exome sequencing (WES) experiments from 50 unrelated donors. Additionally, as a validation, we also used paired WGS/WES datasets of 54 individuals from the 1000 Genomes Project. Finally, we evaluated the tools on data from third-generation HTS obtained from a subset of donors and one reference sample. Our results show that WES, despite typically offering less genealogical resolution than WGS, is an effective method for determining the NRY haplogroup. Y-LineageTracker and Yleaf showed the highest accuracy for WGS data, classifying precisely 98% and 96% of the samples, respectively. Yleaf outperforms all benchmarked tools in the WES data, classifying approximately 90% of the samples. Yleaf, Y-LineageTracker, and pathPhynder can correctly classify most samples (88%) sequenced with third-generation HTS. As a result, Yleaf provides the best performance for applications that use WGS and WES. Overall, our study offers researchers with a guide that allows them to select the most appropriate tool to analyze the NRY region using both second- and third-generation HTS data.

The Qatari population's genetic structure and gene flow as revealed by the Y chromosome

The Y-chromosome has been widely used in forensic genetic applications and human population genetic studies due to its uniparental origins. A large database on the Qatari population was created for comparison with other databases from the Arabian Peninsula, the Middle East, and Africa. We provide a study of 23 Y-STR loci included in PowerPlex Y23 (Promega, USA) that were genotyped to produce haplotypes in 379 unrelated males from Qatar, a country at the crossroads of migration patterns. Overall, the most polymorphic locus provided by the Promega kit was DYS458, with a genetic diversity value of 0.85 and a haplotype diversity of 0.998924. Athey's Haplogroup Predictor tool was used to predict haplogroups from Y-STR haplotypes in the Qatari population. In a median-joining network, the haplogroup J1 predominance (49%) in Qatar generated a star-like expansion cluster. The graph of population Q-matrix was developed using Y-STR data from 38 Middle Eastern and 97 African populations (11,305 individuals), and it demonstrated a stronger sub-grouping of countries within each ethnic group and showed the effect of Arabs on the indigenous Berbers of North Africa. The estimated migration rate between the Qatari and other Arabian populations was inferred using Bayesian coalescence theory in the Migrate-n program. According to the Gene Flow study, the main migration route was from Yemen to Kuwait through Qatar. Our research, using the PowerPlex Y23 database, shows the importance of gene diversity, as well as regional and social structuring, in determining the utility of demographic and forensic databases.

Comprehensive insights into the genetic background of Chinese populations using Y chromosome markers

China is located in East Asia. With a high genetic and cultural diversity, human migration in China has always been a hot topic of genetics research. To explore the origins and migration routes of Chinese males, 3333 Chinese individuals (Han, Hui, Mongolia, Yi and Kyrgyz) with 27 Y-STRs and 143 Y-SNPs from published literature were analysed. Our data showed that there are five dominant haplogroups (O2-M122, O1-F265, C-M130, N-M231, R-M207) in China. Combining analysis of haplogroup frequencies, geographical positions and time with the most recent common ancestor (TMRCA), we found that haplogroups C-M130, N-M231 and R1-M173 and O1a-M175 probably migrated into China via the northern route. Interestingly, we found that haplogroup C*-M130 in China may originate in South Asia, whereas the major subbranches C2a-L1373 and C2b-F1067 migrated from northern China. The results of BATWING showed that the common ancestry of Y haplogroup in China can be traced back to 17 000 years ago, which was concurrent with global temperature increases after the Last Glacial Maximum.

MPKin-YSTR: Interpretation of Y chromosome STR haplotypes for missing persons cases

Y chromosome Short Tandem Repeat (STR) haplotypes have been used in assisting forensic investigations primarily for identification and male lineage determination. The current SWGDAM interpretation guidelines for Y-STR typing provide helpful guidance on those purposes but do not address the issue of kinship analysis with Y-STR haplotypes. Because of the high mutation rate of Y-STRs, there are complex missing person cases in which inconsistent Y-STR haplotypes between true paternal lineage relatives will arise and cases with two or more male references in the same lineage and yet differ in their haplotypes. Therefore, more useful methods are needed for interpreting the Y-STR haplotype data. Computational methods and interpretation guidelines have been developed specifically addressing this issue, either using a mismatch-based counting method or a pedigree likelihood ratio method. In this study, a software program, MPKin-YSTR, was developed by implementing those more sophisticated methods. This software should be able to improve the interpretation of complex cases with Y-STR haplotype evidence. Thus, more biological evidence will be interpreted, which in turn will result in more investigation leads to help solve crimes.

Recent advances in Forensic DNA Phenotyping of appearance, ancestry and age

Forensic DNA Phenotyping (FDP) comprises the prediction of a person's externally visible characteristics regarding appearance, biogeographic ancestry and age from DNA of crime scene samples, to provide investigative leads to help find unknown perpetrators that cannot be identified with forensic STR-profiling. In recent years, FDP has advanced considerably in all of its three components, which we summarize in this review article. Appearance prediction from DNA has broadened beyond eye, hair and skin color to additionally comprise other traits such as eyebrow color, freckles, hair structure, hair loss in men, and tall stature. Biogeographic ancestry inference from DNA has progressed from continental ancestry to sub-continental ancestry detection and the resolving of co-ancestry patterns in genetically admixed individuals. Age estimation from DNA has widened beyond blood to more somatic tissues such as saliva and bones as well as new markers and tools for semen. Technological progress has allowed forensically suitable DNA technology with largely increased multiplex capacity for the simultaneous analysis of hundreds of DNA predictors with targeted massively parallel sequencing (MPS). Forensically validated MPS-based FDP tools for predicting from crime scene DNA i) several appearance traits, ii) multi-regional ancestry, iii) several appearance traits together with multi-regional ancestry, and iv) age from different tissue types, are already available. Despite recent advances that will likely increase the impact of FDP in criminal casework in the near future, moving reliable appearance, ancestry and age prediction from crime scene DNA to the level of detail and accuracy police investigators may desire, requires further intensified scientific research together with technical developments and forensic validations as well as the necessary funding.

Multiple founding paternal lineages inferred from the newly-developed 639-plex Y-SNP panel suggested the complex admixture and migration history of Chinese people

BACKGROUND

Non-recombining regions of the Y-chromosome recorded the evolutionary traces of male human populations and are inherited haplotype-dependently and male-specifically. Recent whole Y-chromosome sequencing studies have identified previously unrecognized population divergence, expansion and admixture processes, which promotes a better understanding and application of the observed patterns of Y-chromosome genetic diversity.

RESULTS

Here, we developed one highest-resolution Y-chromosome single nucleotide polymorphism (Y-SNP) panel targeted for uniparental genealogy reconstruction and paternal biogeographical ancestry inference, which included 639 phylogenetically informative SNPs. We genotyped these loci in 1033 Chinese male individuals from 33 ethnolinguistically diverse populations and identified 256 terminal Y-chromosomal lineages with frequency ranging from 0.0010 (singleton) to 0.0687. We identified six dominant common founding lineages associated with different ethnolinguistic backgrounds, which included O2a2b1a1a1a1a1a1a1-M6539, O2a1b1a1a1a1a1a1-F17, O2a2b1a1a1a1a1b1a1b-MF15397, O2a2b2a1b1-A16609, O1b1a1a1a1b2a1a1-F2517, and O2a2b1a1a1a1a1a1-F155. The AMOVA and nucleotide diversity estimates revealed considerable differences and high genetic diversity among ethnolinguistically different populations. We constructed one representative phylogenetic tree among 33 studied populations based on the haplogroup frequency spectrum and sequence variations. Clustering patterns in principal component analysis and multidimensional scaling results showed a genetic differentiation between Tai-Kadai-speaking Li, Mongolic-speaking Mongolian, and other Sinitic-speaking Han Chinese populations. Phylogenetic topology inferred from the BEAST and Network relationships reconstructed from the popART further showed the founding lineages from culturally/linguistically diverse populations, such as C2a/C2b was dominant in Mongolian people and O1a/O1b was dominant in island Li people. We also identified many lineages shared by more than two ethnolinguistically different populations with a high proportion, suggesting their extensive admixture and migration history.

CONCLUSIONS

Our findings indicated that our developed high-resolution Y-SNP panel included major dominant Y-lineages of Chinese populations from different ethnic groups and geographical regions, which can be used as the primary and powerful tool for forensic practice. We should emphasize the necessity and importance of whole sequencing of more ethnolinguistically different populations, which can help identify more unrecognized population-specific variations for the promotion of Y-chromosome-based forensic applications.

Real-world data on renal transplantations from a tertiary-care hospital in North India, in context of Indian regulatory act-transplantation of human organs and tissues act (THOTA): A retrospective analysis

INTRODUCTION

Renal transplantation is the treatment of choice for patients suffering from end stage renal disease (ESRD). Indian regulations defined under Transplantation of Human Organs and Tissues Act (THOTA), 2014 restricts organ donations to near-related living donors to curb any malpractices like 'paid donors' in living-donor kidney transplantation (LDKT). The aim of our study was to look at real-world data of donor-recipient pairs and to identify relationship of donors (with their respective patients) and the common (or uncommon) DNA profiling methods used for supporting "claimed relationship" in accordance with the regulations.

MATERIAL AND METHODS

The donors were categorized and grouped into near-related donor, donors other than near-related donors, swap donors and deceased donors. Claimed relationship was confirmed, commonly by HLA typing, using SSOP method. In few cases, which were uncommon (and infrequent), autosomal DNA analysis, mitochondrial DNA analysis and Y-STR DNA analysis were performed to support the claimed relationship. Data collected included age, gender, relationship, DNA profiling test method.

RESULTS

Among the 514 donor-recipient pairs evaluated, numbers of female donors out-numbered male donors. The decreasing order of relationships in near-related donor group were wife>mother>father>sister>son>brother>husband> daughter>grandmother. 11.9% of donors were in the category of donors other than near-related donors. In 97.86% cases, the claimed relationship was supported by HLA typing and in just 2.1% cases autosomal DNA analysis>mitochondrial DNA analysis> Y-STR DNA analysis, in this order, were performed to establish relationship.

CONCLUSION

This study brought out gender disparity with women out-numbering men as donors. Among recipients, access to renal transplant was largely restricted to men. As far as relationship of donors to recipients was concerned, mostly near-related family members, like wife, were donors and claimed relationship was almost always (99%) was corroborated by HLA typing.

Forty years of research and development on forensic genetics: A bibliometric analysis

The current study aims to investigate the research publication trends in the field of forensic genetics using Bibliometric analysis. An extensive search of the Scopus database was conducted to identify scholarly articles on forensic genetics published between 1977 and 2022, and a data set comprising 2945 articles was obtained. The analysis was carried out using VOSviewer, RStudio, MS Excel and MS Access to investigate the annual publication trend, most productive journals, organizations/authors/countries, authorship and citation patterns, most cited documents/articles and co-occurrence of keywords. The results revealed the first article in the field of forensic genetics was published in 1977. By the end of 1999, only 15 articles were published. Since then, there has been a considerable increase in the yearly number of publications and post-2006, there were more than 100 yearly published articles. USA, China, Spain, Germany and United Kingdom were found to be the most productive countries. Among various organizations, the Institute of Legal Medicine, Innsbruck Medical University, Austria was found to be the most productive organization. In terms of the number of publications and citations, Morling N. was found to be the most prolific author. The highest number of articles were published in Forensic Science International: Genetics, contributing about 34% of the total articles published in different sources/journals. The document with the highest number of citations was "HOMER N, 2008, PLOS GENET", with a total of 750 citations. The most frequent keywords were forensic genetics and forensic science, followed by STR, population genetics, DNA, mt-DNA and DNA-typing. The results also revealed that there had been collaborative research among countries, organizations and authors, which helps in the exchange of ideas across disciplines, developing new skills, getting access to financial resources and generating quality results.

Single-cell transcriptome sequencing allows genetic separation, characterization and identification of individuals in multi-person biological mixtures

Identifying individuals from biological mixtures to which they contributed is highly relevant in crime scene investigation and various biomedical research fields, but despite previous attempts, remains nearly impossible. Here we investigated the potential of using single-cell transcriptome sequencing (scRNA-seq), coupled with a dedicated bioinformatics pipeline (De-goulash), to solve this long-standing problem. We developed a novel approach and tested it with scRNA-seq data that we de-novo generated from multi-person blood mixtures, and also in-silico mixtures we assembled from public single individual scRNA-seq datasets, involving different numbers, ratios, and bio-geographic ancestries of contributors. For all 2 up to 9-person balanced and imbalanced blood mixtures with ratios up to 1:60, we achieved a clear single-cell separation according to the contributing individuals. For all separated mixture contributors, sex and bio-geographic ancestry (maternal, paternal, and bi-parental) were correctly determined. All separated contributors were correctly individually identified with court-acceptable statistical certainty using de-novo generated whole exome sequencing reference data. In this proof-of-concept study, we demonstrate the feasibility of single-cell approaches to deconvolute biological mixtures and subsequently genetically characterise, and individually identify the separated mixture contributors. With further optimisation and implementation, this approach may eventually allow moving to challenging biological mixtures, including those found at crime scenes.

Genetic polymorphism of 27 Y-STR loci in Kazakh populations from Eastern Kazakhstan

BACKGROUND

The establishment of a national haplotype database is important for forensic and genetic applications and requires studying genetic polymorphisms at Y-STR sites. However, the genetic structure of the Eastern Kazakhstan population is poorly characterised.

AIM

To investigate the genetic polymorphisms of 27 Y-STR loci in the Kazakh population from Eastern Kazakhstan and analyse the population genetic relationships of the Eastern Kazakhs with other populations.

SUBJECTS AND METHODS

The Yfiler Plus kit was utilised to genotype 246 healthy, unrelated males from Eastern Kazakhstan. Based on the raw data, haplotype and allele frequencies along with forensic parameters were calculated, and an MDS plot was constructed.

RESULTS

A total of 207 haplotypes were detected, of which 186 were unique. The haplotype diversity and discrimination capacity were 0.997 and 0.841, respectively. Population comparisons showed that Eastern Kazakhs have close genetic relationships with Kazakhs from Xinjiang, China. At the same time, a difference was found between the studied population and the previous one in the same part of Kazakhstan.

CONCLUSIONS

The obtained haplotypes will help to expand the Kazakhstan Y-chromosome reference database and will be useful for future genetic research and forensic applications.

NanoSTR: A method for detection of target short tandem repeats based on nanopore sequencing data

Short tandem repeats (STRs) are widely present in the human genome. Studies have confirmed that STRs are associated with more than 30 diseases, and they have also been used in forensic identification and paternity testing. However, there are few methods for STR detection based on nanopore sequencing due to the challenges posed by the sequencing principles and the data characteristics of nanopore sequencing. We developed NanoSTR for detection of target STR loci based on the length-number-rank (LNR) information of reads. NanoSTR can be used for STR detection and genotyping based on long-read data from nanopore sequencing with improved accuracy and efficiency compared with other existing methods, such as Tandem-Genotypes and TRiCoLOR. NanoSTR showed 100% concordance with the expected genotypes using error-free simulated data, and also achieved >85% concordance using the standard samples (containing autosomal and Y-chromosomal loci) with MinION sequencing platform, respectively. NanoSTR showed high performance for detection of target STR markers. Although NanoSTR needs further optimization and development, it is useful as an analytical method for the detection of STR loci by nanopore sequencing. This method adds to the toolbox for nanopore-based STR analysis and expands the applications of nanopore sequencing in scientific research and clinical scenarios. The main code and the data are available at https://github.com/langjidong/NanoSTR.

Validation of phylogenetic informative Y-InDels in Y-chromosomal haplogroup O-M175

The Y-chromosomal haplogroup tree, which consists of a group of Y-chromosomal loci with phylogenetic information, has been widely applied in anthropology, archaeology and population genetics. With the continuous updating of the phylogenetic structure, Y-chromosomal haplogroup tree provides more information for recalling the biogeographical origin of Y chromosomes. Generally, Y-chromosomal insertion-deletion polymorphisms (Y-InDels) are genetically stable as Y-chromosomal single nucleotide polymorphisms (Y-SNPs), and therefore carry mutations that can accumulate over generations. In this study, potential phylogenetic informative Y-InDels were filtered out in haplogroup O-M175, which is dominant in East Asia, based on population data retrieved from the 1000 Genomes Project. A group of 22 phylogenetic informative Y-InDels were identified and then assigned to their corresponding subclades of haplogroup O-M175, which provided a supplement for the update and application of Y-chromosomal markers. Especially, four Y-InDels were introduced to define subclades determined using a single Y-SNP.

Revisiting informed consent in forensic genomics in light of current technologies and the times

Informed consent is based on basic ethical principles that should be considered when conducting biomedical and behavioral research involving human subjects. These principles-respect, beneficence, and justice-form the foundations of informed consent which in itself is grounded on three fundamental elements: information, comprehension, and voluntary participation. While informed consent has focused on human subjects and research, the practice has been adopted willingly in the forensic science arena primarily to acquire reference samples from family members to assist in identifying missing persons. With advances in molecular biology technologies, data mining, and access to metadata, it is important to assess whether the past informed consent process and in particular associated risks are concomitant with these increased capabilities. Given the state-of-the-art, areas in which informed consent may need to be modified and augmented are as follows: reference samples from family members in missing persons or unidentified human remains cases; targeted analysis of an individual(s) during forensic genetic genealogy cases to reduce an investigative burden; donors who provide their samples for validation studies (to include population studies and entry into databases that would be applied to forensic statistical calculations) to support implementation of procedures and operations of the forensic laboratory; family members that may contribute samples or obtain genetic information from a molecular autopsy; and use of medical and other acquired samples that could be informative for identification purposes. The informed consent process should cover (1) purpose for collection of samples; (2) process to analyze the samples (to include type of data); (3) benefits (to donor, target, family, community, etc. as applicable); (4) risks (to donor, target, family, community, etc. as applicable); (5) access to data/reports by the donor; (6) sample disposition; (7) removal of data process (i.e., expungement); (8) process to ask questions/assessment of comprehension; (9) follow-up processes; and (10) voluntary, signed, and dated consent. Issues surrounding these topics are discussed with an emphasis on addressing risk factors. Addressing informed consent will allow human subjects to make decisions voluntarily and with autonomy as well as secure the use of samples for intended use.

Developmental validation of a 381 Y-chromosome SNP panel for haplogroup analysis in the Chinese populations

Y-chromosome single nucleotide polymorphism (Y-SNP) shows great variation in geographical distribution and population heterogeneity and can be used to map population genetics around the world. Massive parallel sequencing (MPS) methodology enables high-resolution Y-SNP haplogrouping for a certain male and is widely used in forensic genetics and evolutionary studies. In this present study, we used MPS to develop a customized 381 Y-SNP panel (SifaMPS 381 Y-SNP panel) to investigate the basic structure and subbranches of the haplogroup tree of the Chinese populations. The SifaMPS 381 Y-SNP panel covers all the Y-SNPs from our previously designed 183 Y-SNP panel and additional SNPs under the predominant haplogroups in the Chinese populations based on certain criteria. We also evaluated the sequencing matrix, concordance, sensitivity, repeatability of this panel and the ability to analyze mixed and case-type samples based on the Illumina MiSeq System. The results demonstrated that the novel MPS Y-SNP panel possessed good sequencing performance and generated accurate Y-SNP genotyping results. Although the recommended DNA input was greater than 1.25 ng, we observed that a lower DNA amount could still be used to analyze haplogroups correctly. In addition, this panel could handle mixed samples and common case-type samples and had higher resolution among Chinese Han males than previously reported. In conclusion, the SifaMPS 381 Y-SNP panel showed an overall good performance and offers a better choice for Y-SNP haplogrouping of the Chinese population, thereby facilitating paternal lineage classification, familial searching and other forensic applications.

Development and validation of a new multiplex for upgrading Y-STRs population databases from 12 to 23 markers and its forensic casework application

Y chromosomal short tandem repeats (Y-STRs) are used in forensic investigations as a useful complementary tool to autosomal markers. The ongoing development of new kits with an increasing number of markers makes it necessary to update populations typed in the Y-STR Haplotype Reference Database to reach at least 23 Y-STRs. A novel Y-STR multiplex panel was developed to offer a cost-efficient alternative to update Y-STR haplotypes from 12 to 23 loci. This panel includes the eleven markers, DYS448, DYS456, DYS458, DYS635, Y-GATA H4, DYS576, DYS481, DYS549, DYS533, DYS570 and DYS643, as well as DYS385a/b for traceability purpose. Developmental validation of this panel was conducted following the recommendations of the Scientific Working Group on DNA Analysis Methods (SWGDAM), showing high sensitivity, tolerance to common inhibitors as well as high species specificity. It was efficient for degraded DNA samples and for detection of male mixtures. When applying it for extending the current data of the Ibiza population, both the discrimination capacity and the haplotype diversity increased from 0.5952 to 0.9048 and from 0.9808 to 0.9977, respectively. Together, the study demonstrates the suitability of this panel in forensic casework.

Allelic and haplotypic polymorphisms and paternal genetic analysis of Chinese Shaanxi Han population utilizing a multiplex Y-STR set

BACKGROUND

The analysis of Y chromosomal genetic markers is of great significance in human genetic fields related to male individuals. The Han nationality is the most populous ethnic group. It is critical to investigate the Y-chromosome short tandem repeat (Y-STR) genetic informativeness of Han nationalities in different Chinese regions in order to gain a comprehensive understanding of their paternal genetic relationships and origin.

AIM

To assess the allelic and haplotypic polymorphisms of the novel AGCU Y SUPP STR amplification system containing seven Y-STRs in the maximal dataset of the Y-STR Haplotype Reference Database (YHRD) and 17 newly included Y-STRs, and explore the genetic relationships among the Shaanxi Han population and 12 reference populations from China.

SUBJECTS AND METHODS

A total sample of 220 Han male subjects were obtained from the Shaanxi Province, China, and genotyped by the novel AGCU Y SUPP STR amplification system. Multiplex population genetic analyses derived from the same 16 Y-STR loci were carried out among the Shaanxi Han population and 12 reference populations from China.

RESULTS

The gene diversities (GD) ranged from the maximum value of 0.9609 (DYS385a,b) to the minimum value of 0.5441 (DYS531). Besides, 217 distinct haplotypes were detected wholly in 220 individuals, of which 214 (98.62%) were exclusive. The entire haplotype diversity (HD) and discrimination capacity (DC) were 0.9999 and 0.9864, respectively, while the haplotype match probability (HMP) was 0.0045. Among the reference populations, the obtained results of population genetic analyses revealed that the Shaanxi Han population had the largest genetic distance with the Guangxi Yao group, but the smallest genetic distance with the Hunan Tujia group.

CONCLUSIONS

These Y-STR loci in the AGCU Y SUPP STR amplification system were of high genetic polymorphisms and the amplification system could be used as a prospective complementary tool for forensic application and paternal genetics in the Shaanxi Han population.

Population genetic study of 17 Y-STR Loci of the Sorani Kurds in the Province of Sulaymaniyah, Iraq

Background

The Kurds as an ethnic group are believed to be a combination of earlier Indo-European tribes who migrated and inhabited a mountainous area thousands of years ago. However, as it is difficult to describe the precise history of their origin, it is necessary to investigate their population relationship with other geographical and ethnic groups.

Results

Seventeen Short Tandem Repeat markers on the Y chromosome (Y-STR) included in the AmpFLSTR™ Yfiler™ PCR Amplification Kit (Thermo Fisher Scientific, USA) were used to type DNA samples from the Sorani (Central) Kurdish population in Sulaymaniyah province. One hundred fifty-seven haplotypes were obtained from 162 unrelated male individuals. The highest and lowest gene diversities were DYS385a/b (GD = 0.848) and DYS392 (GD = 0.392), respectively. The haplotypes were used to predict the most likely haplogroups in the Sulaymaniyah population.

Conclusion

Haplogroup prediction indicated predominance (28%) of subclade J2 (44/157) in the Sorani Kurds, northeast of Iraq. The pairwise genetic distance results showed that the Kurdish group clustered along with Asian populations, whereas the furthest countries were Europeans and Africans.

Development and validation of a new multiplex Y-STR panel designed to increase the power of discrimination

In an attempt to increase the discrimination capacity (DC) and reduce the adventitious match probability, a 6-dye multiplex Y-chromosomal short tandem repeat (Y-STR) panel named Y34plex was constructed that combined 25 Y-chromosomal markers (DYS456, DYS627, DYS390, DYS570, DYS635, DYS385a/b, DYS448, DYS437, DYS533, DYS449, DYS481, DYS392, DYS391, DYS389I, DYS460, YGATAH4, DYS438, DYS389II, DYS19, DYS458, DYF387S1a/b, DYS439, DYS393, DYS576, and DYS518) in widely used commercial kits, with nine highly polymorphic Y-STR loci (DYS557, DYS527a/b, DYS593, DYS444, DYS596, DYS643, DYS447, DYS549, and DYS645). The Y34plex is a promising type system to distinguish both unrelated and related male individuals due to the incorporation of rapidly mutated Y-STR loci. A validation study of the Y34plex was performed and followed the guidelines of the Scientific Working Group on DNA analysis methods. Results show that full Y-STR profiles were obtained from male/female DNA mixtures with 125 pg of male DNA in the presence of 50 ng of female DNA. The ability to tolerate polymerase chain reaction inhibitors commonly contained in forensic casework samples demonstrated the applicability and robustness of the Y34plex. Compared with the Yfiler Plus kit, the novel panel showed an increased power of discrimination in Chinese Wuxi Han population (n = 434). The overall haplotype diversity of the Y34plex was 0.999606, whereas DC value was 0.956221, which is suitable for use on forensic paternal investigation.

Design and development of novel single multiplex system incorporating 26 rapidly mutating Y-STRs; 26 RM Yplex

This article details the development of a single multiplex system amplifying 26 rapidly mutating Y-STR markers. A sequenced allelic ladder, constructed for calling alleles of all loci, is introduced. The multiplex system shows the ability to address the limitations of Y-STRs commercial kits in differentiating closely related males. The multiplex performed well in the prevalidation tests and showed great potential to be used in forensic casework.

Y Chromosome Haplotypes Enlighten Origin, Influence, and Breeding History of North African Barb Horses

In horses, demographic patterns are complex due to historical migrations and eventful breeding histories. Particularly puzzling is the ancestry of the North African horse, a founding horse breed, shaped by numerous influences throughout history. A genetic marker particularly suitable to investigate the paternal demographic history of populations is the non-recombining male-specific region of the Y chromosome (MSY). Using a recently established horse MSY haplotype (HT) topology and KASP™ genotyping, we illustrate MSY HT spectra of 119 Barb and Arab-Barb males, collected from the Maghreb region and European subpopulations. All detected HTs belonged to the Crown haplogroup, and the broad MSY spectrum reflects the wide variety of influential stallions throughout the breed’s history. Distinct HTs and regional disparities were characterized and a remarkable number of early introduced lineages were observed. The data indicate recent refinement with Thoroughbred and Arabian patrilines, while 57% of the dataset supports historical migrations between North Africa and the Iberian Peninsula. In the Barb horse, we detected the HT linked to Godolphin Arabian, one of the Thoroughbred founders. Hence, we shed new light on the question of the ancestry of one Thoroughbred patriline. We show the strength of the horse Y chromosome as a genealogical tool, enlighten recent paternal history of North African horses, and set the foundation for future studies on the breed and the formation of conservation breeding programs.