Integrative lncRNA, circRNA, and mRNA analysis reveals expression profiles of six forensic body fluids/tissue.

RNAs have attracted much attention in forensic body fluid/tissue identification (BFID) due to their tissue-specific expression characteristics. Among RNAs, long RNAs (e.g., mRNA) have a higher probability of containing more polymorphic sites that can be used to assign the specific donor of the body fluid/tissue. However, few studies have characterized their overall profiles in forensic science. In this study, we sequenced the transcriptomes of 30 samples from venous blood, menstrual blood, semen, saliva, vaginal secretion, and skin tissue, obtaining a comprehensive picture of mRNA, lncRNA, and circRNA profiles. A total of 90,305 mRNAs, 102,906 lncRNAs (including 19,549 novel lncRNAs), and 40,204 circRNAs were detected. RNA type distribution, length distribution, and expression distribution were presented according to their annotation and expression level, and many novel body fluid/tissue-specific RNA markers were identified. Furthermore, the cognate relations among the three RNAs were analyzed according to gene annotations. Finally, SNPs and InDels from RNA transcripts were genotyped, and 21,611 multi-SNP and 4,471 multi-InDel transcriptomic microhaplotypes (tMHs) were identified. These results provide a comprehensive understanding of transcriptome profiles, which could provide new avenues for tracing the origin of the body fluid/tissue and identifying an individual.

DNA and protein analyses of hair in forensic genetics.

Hair is one of the most common pieces of biological evidence found at a crime scene and plays an essential role in forensic investigation. Hairs, especially non-follicular hairs, are usually found at various crime scenes, either by natural shedding or by forcible shedding. However, the genetic material in hairs is usually highly degraded, which makes forensic analysis difficult. As a result, the value of hair has not been fully exploited in forensic investigations and trials. In recent years, with advances in molecular biology, forensic analysis of hair has achieved remarkable strides and provided crucial clues in numerous cases. This article reviews recent developments in DNA and protein analysis of hair and attempts to provide a comprehensive solution to improve forensic hair analysis.

Comparison of three massively parallel sequencing platforms for single nucleotide polymorphism (SNP) genotyping in forensic genetics.

Three MPS platforms are being used in forensic genetic analysis, i.e., MiSeq FGx, Ion S5 XL, and MGISEQ-2000. However, few studies compared their performance. In this study, we sequenced 83 common SNPs of 71 samples using the ForenSeq™ DNA Signature Prep Kit on MiSeq FGx, the Precision ID Identity Panel on Ion S5 XL, and the MGIEasy Signature Identification Library Prep Kit on MGISEQ-2000 and then the performance was compared. Results showed that the MiSeq FGx had the highest sequence quality but the lowest sequencing depth and allele balance. Discordant genotypes were observed at six SNPs, which may be caused by variants at primer binding regions, indel errors, or misalignments. Besides, two kinds of background noises, allele-specific miscalled reads (ASMR) and allele-nonspecific miscalled reads (ANMR), were characterized. MGISEQ-2000 showed the highest level of ASMR while Ion S5 XL had the highest level of ANMR. Site- and genotype-dependent miscalled patterns were observed at several SNPs on Ion S5 XL and MGISEQ-2000, but few on MiSeq FGx. In conclusion, the three MPS platforms perform differently with respect to sequencing quality, sequencing depth, allele balance, concordance, and background noise. These findings may be useful for data comparison, mixture deconvolution, and heteroplasmy analysis in forensic genetics.

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/ .

Evaluation of Detection Efficiency for Trio Full Sibling Testing.

OBJECTIVES: To study the detection efficiency of trio full sibling with another known full sibling reference added under different number of autosomal STR typing systems. METHODS: Based on 43 detection systems consisting of 13 to 55 representative autosomal STR loci, 10 000 true families (full sibling group) and 10 000 false families (unrelated individual group) were randomly simulated. The full sibling index (FSI) was calculated based on the method of family reconstruction. The cumulative sibling relationship index (CFSI) of 0.000 1 and 10 000 were used as the evaluation thresholds, and the detection efficiency parameters were calculated and compared with the identification of the duo full sibling testing. RESULTS: With the increasing number of STR loci, the error rate and inability of judgement rate gradually decreased; the sensitivity, specificity, correct rate of judgment and other parameters gradually increased, and the system efficiency gradually improved. Under the same detection system, trio full sibling testing showed higher sensitivity, specificity, system efficiency and lower inability of judgement rate compared with duo full sibling testing. When the system efficiency was higher than 0.85 and inability of judgement rate was less than 0.01%, at least 20 STRs should be detected for trio full sibling testing, which was less than 29 STRs required by duo full sibling testing. CONCLUSIONS: The detection efficiency of trio full sibling testing is superior to that of duo full sibling testing with the same detection system, which is an effective identification scheme for laboratories with inadequate detection systems or for materials with limited conditions.

Development and validation of a new 18 X-STR typing assay for forensic applications.

With a unique inheritance pattern compared to autosomal short tandem repeats (A-STRs), X chromosomal STRs (X-STRs) have special usage in forensic relationship testing. In this study, we designed a multiplex amplification system (named TYPER-X19 multiplex assay) consisting of 18 STR loci spreading from 7.837 to 149.460 Mb on the X chromosomes (DXS9895, DXS8378, DXS9902, DXS6810, DXS7132, DXS10079, DXS6789, DXS7424, DXS101, DXS6797, DXS7133, DXS6804, GATA165B12, DXS10103, HPRTB, GATA31E08, DXS8377, and DXS7423), and the amelogenin. PCR primers were marked with four kinds of fluorophores including FAM, HEX, TAMRA, and ROX. The multiplex system was optimized and tested for precision, concordance, reproducibility, sensitivity, stability, DNA mixture, and species specificity according to the conventional validation guidelines. The results indicated that the system was accurate, reliable, and sensitive enough, and was suitable for common forensic case-type samples. In the population genetic study, a total of 148 alleles were detected at the 18 X-STR loci in 398 Southern Han Chinese. Relatively high combined power of discrimination in male (PDm ), power of discrimination in female (PDf ), mean paternity exclusion chance in trios (MECtrio ), and mean paternity exclusion chance in duos (MECDuo ) by Desmarais were detected, and HPRTB-DXS10103 was in linkage disequilibrium. The results suggested that the TYPER-X19 multiplex assay was suitable for forensic applications.

Developmental validation of the MGIEasy Signature Identification Library Prep Kit, an all-in-one multiplex system for forensic applications.

Analyzing genetic markers in nuclear and mitochondrial genomes is helpful in various forensic applications, such as individual identifications and kinship analyses. However, most commercial kits detect these markers separately, which is time-consuming, laborious, and more error-prone (mislabelling, contamination, ...). The MGIEasy Signature Identification Library Prep Kit (hereinafter "MGIEasy identification system"; MGI Tech, Shenzhen, China) has been designed to provide a simple, fast, and robust way to detect appropriate markers in one multiplex PCR reaction: 52 autosomal STRs, 27 X-chromosomal STRs, 48 Y-chromosomal STRs, 145 identity-informative SNPs, 53 ancestry-informative SNPs, 29 phenotype-informative SNPs, and the hypervariable regions of mitochondrial DNA (mtDNA). Here, we validated the performance of MGIEasy identification system following the guidelines of the Scientific Working Group on DNA Analysis Methods (SWGDAM), assessing species specificity, sensitivity, mixture identification, stability under non-optimal conditions (degraded samples, inhibitor contamination, and various substrates), repeatability, and concordance. Libraries prepared using MGIEasy identification system were sequenced on a MGISEQ-2000 instrument (MGI Tech). MGIEasy-derived STR, SNP, and mtDNA genotypes were highly concordant with CE-based STR genotypes (99.79%), MiSeq FGx-based SNP genotypes (99.78%), and Sanger-based mtDNA genotypes (100%), respectively. This system was strongly human-specific, resistant to four common PCR inhibitors, and reliably amplified both low quantities of DNA (as low as 0.125 ng) and degraded DNA (~ 150 nt). Most of the unique alleles from the minor contributor were detected in 1:10 male-female and male-male mixtures; some minor Y-STR alleles were even detected in 1:1000 male-female mixtures. MGIEasy also successfully directly amplified markers from blood stains on FTA cards, filter papers, and swabs. Thus, our results demonstrated that MGIEasy identification system was suitable for use in forensic analyses due to its robust and reliable performance on samples of varying quality and quantity.

Identification and sequencing of 59 highly polymorphic microhaplotypes for analysis of DNA mixtures.

Mixture detection remains one of the major challenges within a forensic science context. In recent years, microhaplotypes were proposed to have great potential in mixture detection, although many of them are not as polymorphic as widely used short tandem repeat (STR) markers. In this study, 59 new highly polymorphic microhaplotypes were identified and sequenced with the NextSeq 500 Sequencer. Based on the whole 1000 Genomes Project dataset, the average effective number of alleles (Ae) of the 59 microhaplotypes was 5.44, and the Ae values of 36 of these microhaplotypes were > 5.00. Their genetic variations in 187 Han Chinese individuals were evaluated. The average allele coverage ratio (ACR) of heterozygotes across all loci was 0.96 ± 0.05. The number of observed alleles varied from 4 to 23, with an average of 8.8 alleles per microhaplotype locus. The average observed heterozygosity (Ho) of 59 loci was 0.77 ± 0.05, and the Ho values of 15 of these loci were > 0.80. All loci showed high polymorphisms with a discrimination power (DP) ranging from 0.80 to 0.97, and the average DP was 0.92 ± 0.03. The analysis of simulated mixtures demonstrated that the microhaplotypes reported here were highly polymorphic and performed well in forensic DNA mixture analysis. This study not only demonstrated the applicability of microhaplotypes in mixture analysis but also provided new choices for highly polymorphic microhaplotypes because after adding the markers identified here, the number of microhaplotypes with Ae values of > 4.00 will increase from ~ 50 to ~ 110.

Comparative evaluation of autosomal STRs and X-chromosome STRs as a complement of autosomal STRs in kinship testing in Southern Han Chinese.

Nowadays, kinship testing is very common in forensic caseworks, but the power of autosomal short tandem repeats (A-STRs) may be limited in complex cases. X-Chromosome short tandem repeats (X-STRs), having a unique heritage mode, should be of special use in some deficient cases. To evaluate and compare the potential of A-STR and X-STR as supplement genetic markers in deficient kinship testing, we simulated 10,000 duos for each of 18 kinds of relationships involving full sibling, half-sibling, grandparent-grandchild, and uncle/aunt-nephew/niece. Loci from STRTyper10, PowerPlex 16, and Investigator Argus X-12 were studied in Southern Han Chinese and the distribution of likelihood ratio (LR) values was analysed. With the addition of the X-12 system, the distribution of LR values for the full sisters, paternal half-sisters, paternal grandmother-granddaughters, maternal aunt-nieces, and maternal aunt-nephews separated much more obviously from those of unrelated duos, and the effectiveness was 1.0000, 0.99865, 0.9991, 0.8996 and 0.9634, respectively, which was more efficient than A-STRs. For the individual duos with other relationships, the effects of adding X-STRs and A-STRs were similar. Therefore, for the Southern Han Chinese, X-STRs can be very useful in kinship testing involving full sisters, paternal half-sisters, paternal grandmother-granddaughters, and maternal aunt-nieces/nephews.

Ethical issues of the research and practice in forensic genetics.

Forensic genetics mainly uses human biological samples as the objects, solves the identification of biological materials related to law by detecting genetic information, provides clues for investigation and evidences for trial, thus facing many ethical issues. This paper put forward the ethical principles in forensic genetics research and practice, and discussed the ethical issues in sample collection, forensic DNA phenotyping, forensic genetic genealogy analysis, forensic DNA database development, paternity and kinship testing, and research data sharing. We suggest that specific ethical requirements should be formulated, the ethical review system should be established for forensic genetics and ethical training for practitioners should be strengthened.

Revisiting the potential power of human leukocyte antigen (HLA) genes on relationship testing by massively parallel sequencing-based HLA typing in an extended family.

The human leukocyte antigen (HLA) genes are the most polymorphic genes in the human genome and have great power in forensic applications, especially in relationship testing and personal identification. However, the extreme polymorphism of HLA has made unambiguous genotyping of these genes very challenging and resulted in the limited application in relationship testing. Fortunately, massively parallel sequencing (MPS) technology offers the promise of unambiguous and high-throughput HLA typing. In this study, 11 HLA genes were typed in one extended family residing in North China and encompassing six generations. Phase-resolved genotypes for HLA genes were generated and HLA haplotype structure was defined. The paternity/kinship index, or in other words, likelihood ratio (LR) was calculated. A total of 88 alleles were identified, of which eight alleles were newly discovered. The inheritance of HLA alleles followed Mendelian law. With the discovery of new HLA alleles and three recombination events, a total of eleven new HLA haplotypes were identified in this population. LR distribution showed that, when HLA alleles were applied, the Log10LR for a single locus could reach very high and the median average Log10LRs of HLA genes were much higher than that of short tandem repeat loci. The result showed that high-throughput HLA genotyping could be achieved rapidly by MPS, and the contribution of HLA genes on system performance could be high, which may be applied as a supplement in forensic genetics studies. This study was also valuable in demonstrating the genetic mechanisms governing the generation of polymorphisms of the HLA genes.

Integrated massively parallel sequencing of 15 autosomal STRs and Amelogenin using a simplified library preparation approach.

Massively parallel sequencing (MPS) technologies, also termed as next-generation sequencing (NGS), are becoming increasingly popular in study of short tandem repeats (STR). However, current library preparation methods are usually based on ligation or two-round PCR that requires more steps, making it time-consuming (about 2 days), laborious and expensive. In this study, a 16-plex STR typing system was designed with fusion primer strategy based on the Ion Torrent S5 XL platform which could effectively resolve the above challenges for forensic DNA database-type samples (bloodstains, saliva stains, etc.). The efficiency of this system was tested in 253 Han Chinese participants. The libraries were prepared without DNA isolation and adapter ligation, and the whole process only required approximately 5 h. The proportion of thoroughly genotyped samples in which all the 16 loci were successfully genotyped was 86% (220/256). Of the samples, 99.7% showed 100% concordance between NGS-based STR typing and capillary electrophoresis (CE)-based STR typing. The inconsistency might have been caused by off-ladder alleles and mutations in primer binding sites. Overall, this panel enabled the large-scale genotyping of the DNA samples with controlled quality and quantity because it is a simple, operation-friendly process flow that saves labor, time and costs.

SNP typing using the HID-Ion AmpliSeq™ Identity Panel in a southern Chinese population.

In the present study, 90 autosomal single nucleotide polymorphisms (SNPs) and 34 Y chromosomal SNPs were sequenced simultaneously using HID-Ion AmpliSeq™ Identity Panel on the Ion PGM™ platform for 125 samples in a southern Chinese population. Raw data were analyzed and forensic parameters were calculated. Haplogrouping concordance was also assessed using alternative methods based on Y-SNP haplotypes and Y-STR haplotypes. The results showed that allelic imbalance occurred more frequently with low coverage while several SNPs with high coverage were also observed with poor allelic balance, including rs214955, rs430046, rs7520386, rs876724, rs9171188, rs16981290, and rs2032631. Totally, 21,261 miscalled reads (0.28%) were observed. The rate of allele-specific miscalled reads (ASMRs) was higher than that of allele nonspecific miscalled reads (ANMRs) and associated with genetic diversity of the SNP. The ASMRs of major allele were lower than that of minor allele while there was no difference for ANMRs. The combined discrimination power (CDP) was 1-4.81 × 10-34 and the combined power of exclusion (CPE) was 0.99989 and 0.99999992 for duo and trio paternity testing, respectively. No significant genetic difference was detected between southern and northern Chinese populations. For haplogroup study, O2 was the predominant haplogroup and 97.01% of samples were assigned consistent haplogoups with Y-SNP and Y-STR haplotypes. In conclusion, the AmpliSeq™ Identity Panel was powerful for individual identification and trio paternity testing. ASMRs were associated with the genetic diversity and allele frequency while neither was related for ANMRs. High concordance of haplogrouping assignment can be obtained with Y-STR and Y-SNP haplotypes.

Evaluation of genetic parameters of 23 autosomal STR loci in a Southern Chinese Han population.

AIM: To evaluate the 23 autosomal short tandem repeat (STR) loci included in GoldenEye™ 25 A kit using forensic human identification and paternity testing. SUBJECTS AND METHODS: In total, 3751 unrelated individuals from the Southern Chinese Han population were genotyped with the 5-dye GoldenEye™ 25 A multiplex amplification system. PCR products were separated using arrayed capillary electrophoresis. Allele frequencies and forensic parameters for the 23 autosomal STR loci were statistically analysed. RESULTS: A total of 344 alleles were observed, with corresponding allelic frequencies ranging from 0.0001-0.5519 for the 23 STR loci. No significant deviation from the Hardy-Weinberg equilibrium and linkage disequilibrium was observed. The combined power of discrimination (CPD) was 1-1.6290 × 10-28 and the combined power of exclusion (CPE) was 0.999 999 999 89 and 0.999 999 286 93 for trio and duo cases, respectively. From 3865 meioses, 87 mutation events were discovered. The mutation rate varied from 0-0.00285 for each locus. One-step mutation accounted for 94.25% of total mutations. The ratio of paternal vs maternal mutation was 3.76:1.13 kinds of n/(n + 1) heterozygote genotypes were observed. CONCLUSIONS: The results show that 23 STR loci of GoldenEye™ 25 A kit are highly polymorphic in the Southern Chinese Han population, indicating the kit is suitable for forensic application.

Tandem amino acid repeats in the green anole (Anolis carolinensis) and other squamates may have a role in increasing genetic variability.

BACKGROUND: Tandem amino acid repeats are characterised by the consecutive recurrence of a single amino acid. They exhibit high rates of length mutations in addition to point mutations and have been proposed to be involved in genetic plasticity. Squamate reptiles (lizards and snakes) diversify in both morphology and physiology. The underlying mechanism is yet to be understood. In a previous phylogenomic analysis of reptiles, the density of tandem repeats in an anole lizard diverged heavily from that of the other reptiles. To gain further insight into the tandem amino acid repeats in squamates, we analysed the repeat content in the green anole (Anolis carolinensis) proteome and compared the amino acid repeats in a large orthologous protein data set from six vertebrates (the Western clawed frog, the green anole, the Chinese softshell turtle, the zebra finch, mouse and human). RESULTS: Our results revealed that the number of amino acid repeats in the green anole exceeded those found in the other five species studied. Species-only repeats were found in high proportion in the green anole but not in the other five species, suggesting that the green anole had gained many amino acid repeats in either the Anolis or the squamate lineage. Since the amino acid repeat containing genes in the green anole were highly enriched in genes related to transcription and development, an important family of developmental genes, i.e., the Hox family, was further studied in a wide collection of squamates. Abundant amino acid repeats were also observed, implying the general high tolerance of amino acid repeats in squamates. A particular enrichment of amino acid repeats was observed in the central class Hox genes that are known to be responsible for defining cervical to lumbar regions. CONCLUSIONS: Our study suggests that the abundant amino acid repeats in the green anole, and possibly in other squamates, may play a role in increasing the genetic variability, and contribute to the evolutionary diversity of this clade.

Hox cluster characterization of Banna caecilian (Ichthyophis bannanicus) provides hints for slow evolution of its genome.

BACKGROUND: Caecilians, with a discrete lifestyle, are the least explored group of amphibians. Though with distinct traits, many aspects of their biology are poorly investigated. Obtaining the caecilian genomic sequences will offer new perspectives and aid the fundamental studies in caecilian biology. The caecilian genomic sequences are also important and practical in the comparative genomics of amphibians. Currently, however, only sparse genomic sequences of caecilians are available. Hox genes, an old family of transcription factors playing central roles in the establishment of metazoan body plan. Understanding their structure and genomic organization may provide insights into the animal's genome, which is valuable for animals without a sequenced genome. RESULTS: We sequenced and characterized the Hox clusters of Banna caecilian (Ichthyophis bannanicus) with a strategy combining long range PCR and genome walking. We obtained the majority of the four caecilian Hox clusters and identified 39 Hox genes, 5 microRNA genes and 1 pseudogene (ψHoxD12). There remained seven intergenic gaps we were unable to fill. From the obtained sequences, the caecilian Hox clusters contained less repetitive sequences and more conserved noncoding elements (CNEs) than the frog counterparts. We found that caecilian and coelacanth shared many more CNEs than frog and coelacanth did. Relative rate of sequence evolution showed that caecilian Hox genes evolved significantly more slowly than the other tetrapod species used in this study and were comparable to the slowly evolving coelacanth Hox genes. Phylogenetic tree of the four Hox clusters also revealed shorter branch length especially for the caecilian HoxA, HoxB and HoxD clusters. These features of the caecilian Hox clusters suggested a slowly evolving genome, which was supported by further analysis of a large orthologous protein dataset. CONCLUSIONS: Our analyses greatly extended the knowledge about the caecilian Hox clusters from previous PCR surveys. From the obtained Hox sequences and the orthologous protein dataset, the caecilian Hox loci and its genome appear evolving comparatively slowly. As the basal lineage of amphibians and land vertebrate, this characteristic of the caecilian genome is valuable in the study concerning the genome biology and evolution of amphibians and early tetrapods.

Metatranscriptomic characterization of six types of forensic samples and its potential application to body fluid/tissue identification: A pilot study.

Microorganisms are potential markers for identifying body fluids (venous and menstrual blood, semen, saliva, and vaginal secretion) and skin tissue in forensic genetics. Existing published studies have mainly focused on investigating microbial DNA by 16 S rRNA gene sequencing or metagenome shotgun sequencing. We rarely find microbial RNA level investigations on common forensic body fluid/tissue. Therefore, the use of metatranscriptomics to characterize common forensic body fluids/tissue has not been explored in detail, and the potential application of metatranscriptomics in forensic science remains unknown. Here, we performed 30 metatranscriptome analyses on six types of common forensic sample from healthy volunteers by massively parallel sequencing. After quality control and host RNA filtering, a total of 345,300 unigenes were assembled from clean reads. Four kingdoms, 137 phyla, 267 classes, 488 orders, 985 families, 2052 genera, and 4690 species were annotated across all samples. Alpha- and beta-diversity and differential analysis were also performed. As a result, the saliva and skin groups demonstrated high alpha diversity (Simpson index), while the venous blood group exhibited the lowest diversity despite a high Chao1 index. Specifically, we discussed potential microorganism contamination and the "core microbiome," which may be of special interest to forensic researchers. In addition, we implemented and evaluated artificial neural network (ANN), random forest (RF), and support vector machine (SVM) models for forensic body fluid/tissue identification (BFID) using genus- and species-level metatranscriptome profiles. The ANN and RF prediction models discriminated six forensic body fluids/tissue, demonstrating that the microbial RNA-based method could be applied to BFID. Unlike metagenomic research, metatranscriptomic analysis can provide information about active microbial communities; thus, it may have greater potential to become a powerful tool in forensic science for microbial-based individual identification. This study represents the first attempt to explore the application potential of metatranscriptome profiles in forensic science. Our findings help deepen our understanding of the microorganism community structure at the RNA level and are beneficial for other forensic applications of metatranscriptomics.

Improved individual identification in DNA mixtures of unrelated or related contributors through massively parallel sequencing.

DNA mixtures are a common sample type in forensic genetics, and we typically assume that contributors to the mixture are unrelated when calculating the likelihood ratio (LR). However, scenarios involving mixtures with related contributors, such as in family murder or incest cases, can also be encountered. Compared to the mixtures with unrelated contributors, the kinship within the mixture would bring additional challenges for the inference of the number of contributors (NOC) and the construction of probabilistic genotyping models. To evaluate the influence of potential kinship on the individual identification of the person of interest (POI), we conducted simulations of two-person (2 P) and three-person (3 P) DNA mixtures containing unrelated or related contributors (parent-child, full-sibling, and uncle-nephew) at different mixing ratios (for 2 P: 1:1, 4:1, 9:1, and 19:1; for 3 P: 1:1:1, 2:1:1, 5:4:1, and 10:5:1), and performed massively parallel sequencing (MPS) using MGIEasy Signature Identification Library Prep Kit on MGI platform. In addition, in silico simulations of mixtures with unrelated and related contributors were also performed. In this study, we evaluated 1): the MPS performance; 2) the influence of multiple genetic markers on determining the presence of related contributors and inferring the NOC within the mixture; 3) the probability distribution of MAC (maximum allele count) and TAC (total allele count) based on in silico mixture profiles; 4) trends in LR values with and without considering kinship in mixtures with related and unrelated contributors; 5) trends in LR values with length- and sequence-based STR genotypes. Results indicated that multiple numbers and types of genetic markers positively influenced kinship and NOC inference in a mixture. The LR values of POI were strongly dependent on the mixing ratio. Non- and correct-kinship hypotheses essentially did not affect the individual identification of the major POI; the correct kinship hypothesis yielded more conservative LR values; the incorrect kinship hypothesis did not necessarily lead to the failure of POI individual identification. However, it is noteworthy that these considerations could lead to uncertain outcomes in the identification of minor contributors. Compared to length-based STR genotyping, using sequence-based STR genotype increases the individual identification power of the POI, concurrently improving the accuracy of mixing ratio inference using EuroForMix. In conclusion, the MGIEasy Signature Identification Library Prep kit demonstrated robust individual identification power, which is a viable MPS panel for forensic DNA mixture interpretations, whether involving unrelated or related contributors.

Somatic GNA11/GNAQ variants in a cohort of Chinese children with phakomatosis pigmentovascularis.

Importance: Postzygotic mutations in the GNAQ/GNA11 genes, which encode the G-protein nucleotide binding protein alpha subunits, have been identified in patients with phakomatosis pigmentovascularis (PPV). However, little is known about the Chinese population. Objective: To identify pathogenic mutations in pediatric patients with PPV within the Chinese population. Methods: We performed whole-exome sequencing (WES) using skin lesion tissues from pediatric patients diagnosed with PPV. Additionally, ultradeep-targeted sequencing was conducted to validate the somatic mutations. A genotype-phenotype correlation was analyzed by integrating data from previous reports with the findings of the present study. Results: Thirteen patients were enrolled, all diagnosed with the cesioflammea type of PPV, except for one patient with an unclassifiable type. We identified somatic GNA11 c.547C>T (p.R183C) variant in seven patients and GNAQ c.548G>A (p.R183Q) in four patients, with low allelic fractions ranging from 2.1% to 8.6% through ultradeep sequencing. Besides, a GNAQ c.548G>A (p.R183Q) variant was detected through targeted sequencing in one of two patients who did not exhibit detectable variants via WES. The genotype-phenotype correlation analysis, involving 15 patients with a GNA11 variant and 10 with a GNAQ variant, revealed that facial capillary malformation (87% vs. 50%, P = 0.075) and ocular melanocytosis (80% vs. 40%, P = 0.087) appeared to be more frequent in patients with GNA11 mutation compared to those with GNAQ mutations. All four patients diagnosed with cesiomarmorata type or overlapping cesioflammea and cesiomarmorata type PPV carried the GNA11 variant. Interpretation: Our study demonstrated that the majority of PPV patients in the Chinese population carried a postzygotic variant of GNAQ/GNA11, thus further confirming the pathogenic role of GNAQ/GNA11 mosaicism in the development of PPV cesioflammea type.

Metavalently bonded tellurides: the essence of improved thermoelectric performance in elemental Te.

Elemental Te is important for semiconductor applications including thermoelectric energy conversion. Introducing dopants such as As, Sb, and Bi has been proven critical for improving its thermoelectric performance. However, the remarkably low solubility of these elements in Te raises questions about the mechanism with which these dopants can improve the thermoelectric properties. Indeed, these dopants overwhelmingly form precipitates rather than dissolve in the Te lattice. To distinguish the role of doping and precipitation on the properties, we have developed a correlative method to locally determine the structure-property relationship for an individual matrix or precipitate. We reveal that the conspicuous enhancement of electrical conductivity and power factor of bulk Te stems from the dopant-induced metavalently bonded telluride precipitates. These precipitates form electrically beneficial interfaces with the Te matrix. A quantum-mechanical-derived map uncovers more candidates for advancing Te thermoelectrics. This unconventional doping scenario adds another recipe to the design options for thermoelectrics and opens interesting pathways for microstructure design.