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Vaginal fluid analysis plays a crucial role in sexual assault investigations. However, vaginal fluid found at crime scenes is usually subject to a certain duration of exposure. This study thus aimed to assess the influence of different durations of exposure to indoor environment on the vaginal microbiota. The 16S rDNA high-throughput sequencing was used on vaginal fluid samples exposed for short-term (30 days) and long-term (240 days), respectively. Despite potential contamination from environmental microorganisms, particularly following long-term exposure, the results indicated that the vaginal microbiota after exposure was still dominated by Lactobacillus. Both in short-term and long-term exposure involving vaginal fluid, there were clusters with time-dependent characteristics, wherein the relative abundances of associated microbial genera showed a trend of increasing or decreasing over time. In addition, each bodily fluid presented with a unique array of dominant bacterial genera, enabling the differentiation of exposed vaginal fluid samples from other bodily fluids (semen, skin, saliva, feces) with a remarkable 98.75 % accuracy rate. Furthermore, the mean absolute error achieved by the long-term deposition time prediction model was 13.54 days. The mean absolute error for the short-term deposition time prediction model was notably lower, reaching just 2.05 days. In summary, this study investigates the variations in microbial communities within vaginal fluid subjected to different indoor exposure durations and explores their potential in body fluid identification and estimating the time since deposition, thereby contributing valuable supporting evidence in forensic investigations.

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Insertion or deletion (InDel), a genetic marker with short insertion/deletion fragment length polymorphism, is widely used in the field of forensic biological research. The Guizhou Shui (Shui) ethnic group and Guizhou Dong (Dong) ethnic group are located in the southwestern region of China, with rich historical and cultural background. In this study, a self-developed panel included 56 ancestry informative marker (AIM)-InDel loci on the autosomes, three InDel loci on the Y chromosome, and one sex-determined Amelogenin locus. Firstly, we used the 56 autosomal loci to assess the forensic individual identification and paternity testing abilities in both the Shui and Dong groups. The cumulative probability of match and probability of exclusion for the Shui and Dong groups were 2.228×10-15 and 0.991518139; 7.604×10-16 and 0.992253273, respectively. In addition, we also conducted in-depth analyses for the genetic backgrounds and structures of the Shui and Dong groups based on 56 AIM-InDel loci. This research has found that the Shui and Dong groups have close genetic relationships with the East Asian populations. Meanwhile, we also found that the Shui group has a close genetic distance with Chinese Dai in Xishuangbanna (CDX). These insights provide vital information for the genetic structures of the Shui and Dong groups, as well as basic population data and molecular biological evidence support for individual identification and biogeographic ancestry inference in forensic genetic field.

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Mitochondrial DNA (mtDNA) is an important genetic marker for degraded biological sample identification, maternal pedigree tracing, and population genetic structure study owing to its characteristics of high copy number, anti-degradable ring structure, and maternal inheritance. Whole mtDNA genome sequencing is an optimal method for the analysis of mtDNA polymorphism and heterogeneity because it allows for the comprehensive use of maternal genetic information. However, because of lacking quantitative evaluations for sequencing data, the scientific interpretation standards for mtDNA sequencing results of the previously used sequencing systems are often different, and false positive or false negative results are prone to occur when faced with the interference of nuclear genomic DNA, or the heterogeneities of mtDNA sequence and structure. In this study, we evaluated a novel mtDNA whole genome sequencing system using long fragment amplification strategy on the DNA nanoball (DNB) sequencing platform. This system demonstrated high sequencing quality and specific mtDNA sequencing efficiencies on positive control DNA and FTA bloodstain samples, as the average Q20 and Q30 values of the corresponding samples were 97.17 % and 91.93 %; 97.37 % and 92.48 %, respectively. The mean mapping percentages for the reference sequences of whole genome DNA (wgDNA), mtDNA, and nuclear genomic DNA (ngDNA) in the corresponding samples were 99.98 %, 99.97 %, 0.03 %, and 99.91 %, 99.40 %, 0.60 %; respectively. The average error calling rates for the bases A, C, G, and T of the whole mtDNA genome were 0.2519 %, 0.2550 %, 0.2906 %; and 0.2392 %, respectively. The efficacy of heteroplasmy identification was assessed using a set of theoretical sites with predetermined rates. These sites were created by combining the samples with known mtDNA haplotypes in certain proportions. The absolute errors between observed and theoretical heteroplasmy values were 89.59 %, 74.68 %, 50.20 %, 12.65 %, 8.31 %, and 4.85 %, while the theoretical heteroplasmy values were 5 %, 10 %, 20 %, 80 %, 90 %, and 95 %, respectively. The absolute error exhibited relative stability when the mtDNA sequencing depth exceeded 500×. Furthermore, the system sequencing efficiency was also confirmed among different kinds of samples, and these samples included natural samples (e.g., peripheral blood samples preserved on FTA cards for 2 and 11 years, and on filter paper for 6 and 9 years), degraded samples, sensitivity samples, samples derived from various bodily fluids, and maternal pedigree samples. In summary, the whole mtDNA genome sequencing system used for forensic identification demonstrated high performance in analyzing mtDNA sequence information, and showed significant prospects for forensic application and maternal genetic research.

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Recently, RNA markers have been used to identify tissue origins of different kinds of body fluids. Herein, circRNA and miRNA markers were carried out to examine the presence or absence of peripheral blood (PB) in bloodstained samples exposed to different external environmental conditions, which mimicked PB samples left at the crime scenes. PB samples were placed on sterile swabs and then exposed to different high temperatures (37°C, 55°C and 95°C) and ultraviolet light irradiation for 0 d, 0.5 d, 1 d, 3 d, and 7 d, ultra-low and low temperatures (-80°C, -20°C, and 4°C) for 30 d, 180 d and 365 d and different kinds of disinfectants. Total RNA was extracted from bloodstained samples under the above different conditions, and the expressions of target RNAs (including miR16-5p, miR451a, circ0000095, and two reference genes RNU6b and 18 S rRNA) were detected by the reverse transcription-quantitative polymerase chain reaction (RT-qPCR) method. Results showed that these selected RNA markers could be successfully measured at all observation points with their unique degradation rates, which exhibited relative stability in degraded bloodstained samples exposed to different environmental conditions. This study provides insights into the applications of these studied miRNA and circRNA markers in forensic science.

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As two kinds of increasingly popular pets, the saliva of cat or canine is most likely to be left at the crime scene compared with the common types of body fluids in forensics. Accurately identifying the species of saliva samples found at the crime scene involving pets will help the investigators find available testing materials, reduce the consumption of reagents and save the investigative time of the case. Therefore, it is necessary to explore the characteristics and differences of saliva microbiomes of cat, canine and human. In this study, 16S rRNA gene amplicon sequencing technology was used to reveal microbial communities of saliva samples of healthy human, cat, and canine. Alpha diversity analyses indicated that canine saliva demonstrated the highest microbial diversity, followed by cat saliva, whereas human saliva microbial diversity was the lowest. The saliva samples of the three species all had their own unique microbial community compositions, and the dominant phyla of canine and cat salivas were Proteobacteria and Bacteroidete, while the dominant phyla of human saliva were Firmicutes and Proteobacteria. There was no significant statistical difference in the salivary microbiota obtained by the two collection methods (cotton swab and liquid saliva). The gender of cats and canines might have no effect on the salivary microbiota, but the different breeds had an impact on their saliva microbiomes. Principal coordinates analysis, non-metric multidimensional scaling analysis and random forest analysis all indicated significant differences in microbial community structures among the three species, allowing inference on the species sources of saliva samples by microbiome method. Differential microbial biomarkers for the salivas of three species were screened out using a variety of bioinformatics analyses, and the results demonstrated that Prevotella melaninogenica, Veillonella parvula, and Haemophilus parainfluenzae could be used as species-specific microbial biomarkers of human saliva. The detections of human species-specific microbes provide a potential method for determining human saliva.

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Periodontitis is a critical risk factor for the occurrence and development of diabetes. Porphyromonas gingivalis may participate in insulin resistance (IR) caused by periodontal inflammation, but the functional role and specific mechanisms of P. gingivalis in IR remain unclear. In the present study, clinical samples were analysed to determine the statistical correlation between P. gingivalis and IR occurrence. Through culturing of hepatocytes, myocytes, and adipocytes, and feeding mice P. gingivalis orally, the functional correlation between P. gingivalis and IR occurrence was further studied both in vitro and in vivo. Clinical data suggested that the amount of P. gingivalis isolated was correlated with the Homeostatic Model Assessment for IR score. In vitro studies suggested that coculture with P. gingivalis decreased glucose uptake and insulin receptor (INSR) protein expression in hepatocytes, myocytes, and adipocytes. Mice fed P. gingivalis tended to undergo IR. P. gingivalis was detectable in the liver, skeletal muscle, and adipose tissue of experimental mice. The distribution sites of gingipain coincided with the downregulation of INSR. Gingipain proteolysed the functional insulin-binding region of INSR. Coculture with P. gingivalis significantly decreased the INSR-insulin binding ability. Knocking out gingipain from P. gingivalis alleviated the negative effects of P. gingivalis on IR in vivo. Taken together, these findings indicate that distantly migrated P. gingivalis may directly proteolytically degrade INSR through gingipain, thereby leading to IR. The results provide a new strategy for preventing diabetes by targeting periodontal pathogens and provide new ideas for exploring novel mechanisms by which periodontal inflammation affects the systemic metabolic state.

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Large-scale genomic projects and ancient DNA innovations have ushered in a new paradigm for exploring human evolutionary history. However, the genetic legacy of spatiotemporally diverse ancient Eurasians within Chinese paternal lineages remains unresolved. Here, we report an integrated Y-chromosome genomic database encompassing 15,563 individuals from both modern and ancient Eurasians, including 919 newly reported individuals, to investigate the Chinese paternal genomic diversity. The high-resolution, time-stamped phylogeny reveals multiple diversification events and extensive expansions in the early and middle Neolithic. We identify four major ancient population movements, each associated with technological innovations that have shaped the Chinese paternal landscape. First, the expansion of early East Asians and millet farmers from the Yellow River Basin predominantly carrying O2/D subclades significantly influenced the formation of the Sino-Tibetan people and facilitated the permanent settlement of the Tibetan Plateau. Second, the dispersal of rice farmers from the Yangtze River Valley carrying O1 and certain O2 sublineages reshapes the genetic makeup of southern Han Chinese, as well as the Tai-Kadai, Austronesian, Hmong-Mien, and Austroasiatic people. Third, the Neolithic Siberian Q/C paternal lineages originated and proliferated among hunter-gatherers on the Mongolian Plateau and the Amur River Basin, leaving a significant imprint on the gene pools of northern China. Fourth, the J/G/R paternal lineages derived from western Eurasia, which were initially spread by Yamnaya-related steppe pastoralists, maintain their presence primarily in northwestern China. Overall, our research provides comprehensive genetic evidence elucidating the significant impact of interactions with culturally distinct ancient Eurasians on the patterns of paternal diversity in modern Chinese populations.

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Insertion/deletion (InDel) polymorphisms can be used as one of the ancestry-informative markers in ancestry analysis. In this study, a self-developed panel consisting of 56 ancestry-informative InDels was used to investigate the genetic structures and genetic relationships between Chinese Inner Mongolia Manchu group and 26 reference populations. The Inner Mongolia Manchu group was closely related in genetic background to East Asian populations, especially the Han Chinese in Beijing. Moreover, populations from northern and southern East Asia displayed obvious variations in ancestral components, suggesting the potential value of this panel in distinguishing the populations from northern and southern East Asia. Subsequently, four machine learning models were performed based on the 56 AIM-InDel loci to evaluate the performance of this panel in ancestry prediction. The random forest model presented better performance in ancestry prediction, with 91.87% and 99.73% accuracy for the five and three continental populations, respectively. The individuals of the Inner Mongolia Manchu group were assigned to the East Asian populations by the random forest model, and they exhibited closer genetic affinities with northern East Asian populations. Furthermore, the random forest model distinguished 87.18% of the Inner Mongolia Manchus from the East Asian populations, suggesting that the random forest model based on the 56 ancestry-informative InDels could be a potential tool for ancestry analysis.

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AIMS: This study aims to investigate the pharmacological effects and the underlying mechanism of cannabidiol (CBD) on methamphetamine (METH)-induced relapse and behavioral sensitization in male mice. METHODS: The conditioned place preference (CPP) test with a biased paradigm and open-field test were used to assess the effects of CBD on METH-induced relapse and behavioral sensitization in male mice. RNA sequencing and bioinformatics analysis was employed to identify differential expressed (DE) circRNAs, miRNAs, and mRNAs in the nucleus accumbens (NAc) of mice, and the interaction among them was predicted using competing endogenous RNAs (ceRNAs) network analysis. RESULTS: Chronic administration of CBD (40 mg/kg) during the METH withdrawal phase alleviated METH (2 mg/kg)-induced CPP reinstatement and behavioral sensitization in mice, as well as mood and cognitive impairments following behavioral sensitization. Furthermore, 42 DEcircRNAs, 11 DEmiRNAs, and 40 DEmRNAs were identified in the NAc of mice. The circMeis2-miR-183-5p-Kcnj5 network in the NAc of mice is involved in the effects of CBD on METH-induced CPP reinstatement and behavioral sensitization. CONCLUSIONS: This study constructed the ceRNAs network for the first time, revealing the potential mechanism of CBD in treating METH-induced CPP reinstatement and behavioral sensitization, thus advancing the application of CBD in METH use disorders.

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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.

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INTRODUCTION: Multiple insertion-deletion (multi-InDel) has greater potential in forensic genetics than InDel, and its efficacy in kinship testing, individual identification, DNA mixture detection and ancestry inference remains to be explored. METHODS: Consequently, we designed an efficient and robust system consisting of 41 multi-InDels to evaluate its efficacy in forensic applications in Chinese Hezhou Han (HZH) and Southern Shaanxi Han (SNH) populations and explore the genetic relationships between the SNH, HZH, and 26 reference populations. RESULTS AND CONCLUSION: The obtained results showed that 38 out of the 41 multi-InDels had fairly high genetic variations. The the cumulative probability of discrimination and exclusion values of the multi-InDels (except MI38) in HZH and SNH populations both exceeded 1-e-25 and 1-e-6, correspondingly. The genetic compositions of HZH and SNH individuals were similar to that of East Asians and the Naive Bayes model could well distinguish East Asians, Africans and Americans. These results indicated that the multi-InDel systerm can serve as an effective tool to provide important evidence for the development of multi-InDels in forensic practice and better analyse the genetic background of the Han Chinese populations.

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This study aimed to investigate the genetic polymorphisms and population characteristics of Chinese Mongolian group from northwest China (NCM) through a self-developed panel including 43 autosomal insertion/deletion (A-InDel) polymorphism genetic markers. Herein, 288 unrelated healthy individuals from the NCM group were employed to obtain the genetic data of 43 A-InDels through multiplex PCR amplification and InDel genotyping using capillary electrophoresis platform. In addition, multiplex population genetic analyses were performed between the NCM group and 27 reference populations. There were no deviations at 43 loci from Hardy-Weinberg equilibrium in the NCM group. The observed heterozygosity (Ho) values ranged from 0.312 8 to 0.559 2, and the combined power of discrimination (CPD) and cumulative probability of exclusion (CPE) values in the NCM group were 0.999 999 999 999 999 998 77 and 0.999 814, respectively. The forensic parameter values indicated that this panel was polymorphic and informative in the NCM group and could be used as an effective tool for forensic personal identification. Furthermore, the results of pairwise genetic distances, principal component analysis, multidimensional scaling analysis, phylogenetic tree construction, and admixture analysis among the NCM group and 27 reference populations revealed that there were closer genetic relationships between the NCM group and East Asian populations, especially Chinese Hui group (CHH) from the northwest China, which is consistent with the geographical location. These present findings contributed to the ongoing genetic explorations and insights into the genetic architecture of the NCM group.

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BACKGROUND: Previously, a novel multiplex system of 64 loci was constructed based on capillary electrophoresis platform, including 59 autosomal insertion/deletions (A-InDels), two Y-chromosome InDels, two mini short tandem repeats (miniSTRs), and an Amelogenin gene. The aim of this study is to evaluate the efficiencies of this multiplex system for individual identification, paternity testing and biogeographic ancestry inference in Chinese Hezhou Han (CHH) and Hubei Tujia (CTH) groups, providing valuable insights for forensic anthropology and population genetics research. RESULTS: The cumulative values of power of discrimination (CDP) and probability of exclusion (CPE) for the 59 A-InDels and two miniSTRs were 0.99999999999999999999999999754, 0.99999905; and 0.99999999999999999999999999998, 0.99999898 in CTH and CHH groups, respectively. When the likelihood ratio thresholds were set to 1 or 10, more than 95% of the full sibling pairs could be identified from unrelated individual pairs, and the false positive rates were less than 1.2% in both CTH and CHH groups. Biogeographic ancestry inference models based on 35 populations were constructed with three algorithms: random forest, adaptive boosting and extreme gradient boosting, and then 10-fold cross-validation analyses were applied to test these three models with the average accuracies of 86.59%, 84.22% and 87.80%, respectively. In addition, we also investigated the genetic relationships between the two studied groups with 33 reference populations using population statistical methods of FST, DA, phylogenetic tree, PCA, STRUCTURE and TreeMix analyses. The present results showed that compared to other continental populations, the CTH and CHH groups had closer genetic affinities to East Asian populations. CONCLUSIONS: This novel multiplex system has high CDP and CPE in CTH and CHH groups, which can be used as a powerful tool for individual identification and paternity testing. According to various genetic analysis methods, the genetic structures of CTH and CHH groups are relatively similar to the reference East Asian populations.

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Identifying the biogeographic ancestral origin of biological sample left at a crime scene can provide important evidence for judicial case, as well as clue for narrowing down suspect. Ancestry informative single nucleotide polymorphism (AISNP) has become one of the most important genetic markers in recent years for screening ancestry information loci and analyzing the population genetic background and structure due to their high number and wide distributions in the human genome. In this study, based on data from 26 populations in the 1000 Genomes Project Phase 3, a Random Forest classification model was constructed with one-vs-rest classification strategy for embedded feature selection in order to obtain a panel with a small number of efficient AISNPs. The research aim was to clarify differentiations of population genetic structures among continents and subregions of East Asia. ADMIXTURE results showed that based on the 58 AISNPs selected by the machine learning algorithm, the 26 populations involved in the study could be categorized into six intercontinental ancestry components: North East Asia, South East Asia, Africa, Europe, South Asia, and America. The 24 continental-specific AISNPs and 34 East Asian-specific AISNPs were finally obtained, and used to construct the ancestry prediction model using XGBoost algorithm, resulting in the Matthews correlation coefficients of 0.94 and 0.89, and accuracies of 0.94 and 0.92, respectively. The machine learning models that we constructed using population-specific AISNPs were able to accurately predict the ancestral origins of continental and intra-East Asian populations. To summarize, screening a set of high-perform AISNPs to infer biogeographical ancestral information using embedded feature selection has potential application in creating a layered inference system that accurately differentiates from intercontinental populations to local subpopulations.

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BACKGROUND: Body fluid traceability inferences can provide important clues to the investigation of forensic cases. Microbiome has been proven to be well applied in forensic body fluid traceability studies. Most of the specimens at crime scenes are often exposed to the external environment when collected, so it is extremely important to exploring the structure characteristics of microbial communities of body fluid samples under different exposure durations for tracing the origin of body fluids based on microorganisms. METHODS: Full-length 16S rRNA sequencing technology and multiple data analysis methods were used to explore the microbial changes in three types of body fluid samples at five different exposure time points. RESULTS: With increasing exposure time, the Proteobacteria abundance gradually increased in the negative control and body fluid samples, and the Bacteroidetes and Firmicutes abundance decreased gradually, but the relative abundance of dominant genera in each body fluid remained dynamically stable. The microbial community structures of those samples from the same individual at different exposure durations were similar, and there were no significant differences in the microbial community structures among the different exposure time points. LEfSe and random forest analyses were applied to screen stable and differential microbial markers among body fluids, such as Streptococcus thermophilus, Streptococcus pneumoniae and Haemophilus parainfluenzae in saliva; Lactobacillus iners and Streptococcus agalactiae in vaginal fluid. CONCLUSIONS: There were no significant differences in microbial community structures of the three types of body fluid samples exposed to the environment for various time periods, although the relative abundance of some microbes in these samples would change. The exposed samples could still be traced back to their source of the body fluid samples using the microbial community structures.

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Although furazolidone (FZD) was completely banned from livestock production in many countries many years ago due to its mutagenicity and carcinogenicity, the abuse of FZD is still common today. Accurate and rapid detection of FZD residues in animal-derived food products is highly important for human health. Here, a time-resolved fluorescence immunochromatography (TRFI) test strip for rapid and quantitative detection of 3-amino-2-oxazolidinone (AOZ) residues in animal foods was developed and validated. Its limit of detection and limit of quantification were 0.05 and 0.14 µg/kg, respectively. The typical recovery rates were 95-105 % in chicken breast samples spiked with the AOZ standard substance at concentrations of 0.05-2 µg/kg, with a coefficient of variation value ≤8.5 %. The cross-reaction rates of the TRFI-AOZ test strips with 3-amino-5-morpholinomethyl-2-oxazolidone, semicarbazide, and 1-amino-imidazolidin-2,4-dione were less than 1 %. The newly developed TRFI test strip has high sensitivity, high specificity, cost effectiveness and user-friendly control, and is suitable for the rapid and large-scale screening of AOZ residues in animal foods.

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The Miao group is one of the representative Hmong-Mien-speaking populations and primarily scattered in southern China and Southeast Asia, which has experienced massive migrations in history and thus forms distinctive evolutionary genetics. Yet, the genetic explorations of Miao group are relatively limited based on complete mitochondrial genome (mitogenome), especially for the Miao group from Yunnan Province (YNM). Here, we sequenced complete mitogenomes of 132 Miao individuals from Yunnan Province using massively parallel sequencing method. Total 132 Miao individuals could be allocated to 119 various haplotypes, which were mainly dominated by haplogroups prevalent in southern East Asia (B, F, M7 and R9), and rarely occupied by northern lineages (A, D, G and M8). In order to dissect the genetic background of YNM more comprehensively, we introduced 99 published population data with 7135 complete mitochondrial sequences for population genetic comparisons. YNM exhibited closer genetic relationships with Hmong-Mien, Tai-Kadai, Sino-Tibetan and Austroasiatic populations, especially for Hmong-Mien populations; we further speculated that Miao group might have certain direct or indirect gene exchanges with ancient Baiyue groups. Several maternal lineages, such as B5a1c1a, F1g1, B4a5 and D4e1a3, were found to be specifically shared by YNM and other Hmong-Mien populations, and these matrilineal expansions occurred roughly during the Neolithic period. Eventually, according to the population dynamic analyses of YNM, the population size began to emerge recovery âˆ¼1-0.5 kya after a long-term population reduction âˆ¼1-5 kya, during which the B5a1c1a haplogroup manifested relatively apparent lineage expansion.

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To address the challenges faced by forensic examiners in degraded DNA analysis, we have developed two different panels for various forensic applications, encompassing an AIM-InDel panel for ancestry inference and a Multi-InDel panel for individual identification, respectively. Herein, the efficiencies of these two panels were tested in the Chinese Hui group. By calculating forensic parameters and simulating family relationships, we verified that the Multi-InDel panel could be an effective tool for individual identification, paternity testing, and could assist in kinship identification in the Hui group. For full siblings, the true positive rate of kinship discrimination was 96.553%, when the threshold of log10LR was 1. The cumulative probability of matching as well as cumulative probability of exclusion were 3.8117 × 10-26 and 0.999999722, respectively. Meanwhile, we found that the AIM-InDel panel was effective for bio-geographic ancestry inference, with the vast majority of loci contributing significantly to distinguish East Asian, African, and European populations. By studying the population structure of the Hui ethnic minority, the genetic distance to the Beijing Han population was the closest among the 26 reference populations, which was similar to previous reports. In summary, we have developed two panels which can be effectively applied to the Hui group for individual identification, parentage testing and bio-geographic ancestry inference.

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The continual investigation of novel genetic markers has yielded promising solutions for addressing the challenges encountered in forensic DNA analysis. In this study, we have introduced a custom-designed panel capable of simultaneously amplifying 41 novel Multi-insertion/deletion (Multi-InDel) markers and an amelogenin locus using the capillary electrophoresis platform. Through a developmental validation study conducted in accordance with guidelines recommended by the Scientific Working Group on DNA Analysis Methods, we demonstrated that the new Multi-InDel system exhibited the sensitivity to produce reliable genotyping profiles with as little as 62.5 pg of template DNA. Accurate and complete genotyping profiles could be obtained even in the presence of specific concentrations of PCR inhibitors. Furthermore, the maximum amplicon size for this system was limited to under 220 bp in the genotyping profile, resulting in its superior efficiency compared to commercially available short tandem repeat kits for both naturally and artificially degraded samples. In the context of mixed DNA analysis, the Multi-InDel system was proved informative in the identification of two-person DNA mixture, even when the template DNA of the minor contributor was as low as 50 pg. In conclusion, a series of performance evaluation studies have provided compelling evidence that the new Multi-InDel system holds promise as a valuable tool for forensic DNA analysis.

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Deletion/insertion polymorphism (DIP) is one of the more promising genetic markers in the field of forensic genetics for personal identification and biogeographic ancestry inference. In this research, we used an in-house developed ancestry-informative marker-DIP system, including 56 autosomal diallelic DIPs, three Y-chromosomal DIPs, and an Amelogenin gene, to analyze the genetic polymorphism and ancestral composition of the Chinese Korean group, as well as to explore its genetic relationships with the 26 reference populations. The results showed that this novel panel exhibited high genetic polymorphism in the studied Korean group and could be effectively applied for forensic individual identification in the Korean group. In addition, the results of multiple population genetic analyses indicated that the ancestral component of the Korean group was dominated by northern East Asia. Moreover, the Korean group was more closely related to the East Asian populations, especially to the Japanese population in Tokyo. This study enriched the genetic data of the Korean ethnic group in China and provided information on the ancestry of the Korean group from the perspective of population genetics.

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