Developmental validation of the Microreader™ Y Prime Plus ID System: An advanced Y-STR 38-plex system for forensic applications

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).

Haplotype and Genetic Analysis of 41 Y-STR Loci in the Wuwei Han Population from Gansu Province, China

OBJECTIVE

Y-Chromosomal short tandem repeat polymorphism (Y-STR) analysis plays an indispensable role in the identification of male individuals, population genetics, and biogeographic research. While profiles of many populations based on Y-STR markers in human genomes are ample, haplotype data for the Wuwei Han are still scarce.

METHODS

In this study, 2180 unrelated Wuwei Han male individuals residing in Gansu Province, China were collected and genotyped using the novel Microreader™ 40Y Plus ID system. Phylogenetic relationship reconstructions, multidimensional scaling (MDS), and heatmap analysis were performed based on the genetic distance (Rst) values between our studied population and other populations of the Ymax module in the Y-STR Haplotype Reference Database (YHRD).

RESULTS

A total of 2129 unique haplotypes were obtained, and the haplotype diversity (HD) and discrimination capacity (DC) for the Wuwei Han were 0.9999 and 0.9931, respectively.

CONCLUSION

Our results demonstrate that the Wuwei Han population had intimate genetic relationships with East Asians, especially the geographically close Han populations. Overall, this Y-Chromosomal assay gives valuable information about paternal lineages in male individual tracking and genealogical database construction.

Improving DNA Data Capacity: Forensic Parameters and Genetic Structure Analysis of Jinjiang Han Population with the Microreader™ Y Prime Plus ID System

OBJECTIVE

Population genetic analysis based on genetic markers harbors valuable forensic applications. In this regard, it is informative and imperative to explore Han groups as they are the largest population of China. In particular, there is a largely underrepresented amount of information from recent decades regarding the southeast costal Han Chinese. Therefore, the aim of this study is to investigate the available genetic characteristics of the Han population living in the Jinjiang, Fujian Province, Southeastern China.

METHODS

We sampled 858 saliva samples and used the commercially available Microreader™ Y Prime Plus ID System to identify population data of Y-short tandem repeat (STR) loci of this region.

RESULTS

A total of 822 different haplotypes were observed. The overall haplotype diversity, discriminatory power and haplotype match probability were 0.9999, 0.9999 and 0.0012, respectively.

CONCLUSION

Our results showed that the Jinjiang Han population was closely genetically related to Han groups of China. Overall, we identified a set of 37 Y-STRs that are highly polymorphic, and that can provide meaningful information in forensic practice and human genetic research.

Developmental Validation of a Rapidly Mutating Y-STR Panel Labeled by Six Fluoresceins for Forensic Research

The male-specific region of the human Y chromosome is a useful genetic marker for genealogical searching, male inheritance testing, and male DNA mixture deconvolution in forensic studies. However, the Y chromosomal short tandem repeats (Y-STRs) are difficult to distinguish among related males due to their low/medium mutation rate. In contrast, rapidly mutating (RM) Y-STRs exhibit unusually high mutation rates and possess great potential for differentiating male lineages. In this study, we developed a novel Y-STRs multiplex amplification assay of 32 RM Y-STRs by fragment analysis using six dye-labeled technologies (FAM, HEX, TAMRA, ROX, VIG, and SIZ). The development and the validation of the kit were carried out in accordance with the Scientific Working Group guidelines on DNA Analysis Methods. Identical allelic profiles of the 32 RM Y-STRs using a DNA 9948 sample as the positive control could be observed at different concentrations of PCR reagents. Further, the RM Y-STRs did not show cross-reactions with other common animal species, and the developed assay could tolerate interferences from common PCR inhibitors and mixed DNA samples. More importantly, the kit showed relatively high sensitivity and could detect trace DNA samples. Genetic distributions of 32 RM Y-STRs in the Guizhou Han population revealed that these RM Y-STRs showed relatively high genetic diversities. In conclusion, the RM Y-STR assay developed here showed good species specificity, high sensitivity, tolerance to inhibitors, and sample compatibility, which can be viewed as a highly efficient tool with high discrimination capacity for forensic male differentiation.