Search

Background & Objective: Sex estimation is a critical aspect of forensic expertise. Some special anatomical structures, such as the maxillary sinus, can still maintain integrity in harsh environmental conditions and may be served as a basis for sex estimation. Due to the complex nature of sex estimation, several studies have been conducted using different machine learning algorithms to improve the accuracy of sex prediction from anatomical measurements., Material & Methods: In this study, linear data of the maxillary sinus in the population of northwest China by using Cone-Beam Computed Tomography (CBCT) were collected and utilized to develop logistic, K-Nearest Neighbor (KNN), Support Vector Machine (SVM) and random forest (RF) models for sex estimation with R 4.3.1. CBCT images from 477 samples of Han population (75 males and 81 females, aged 5-17 years; 162 males and 159 females, aged 18-72) were used to establish and verify the model. Length (MSL), width (MSW), height (MSH) of both the left and right maxillary sinuses and distance of lateral wall between two maxillary sinuses (distance) were measured. 80% of the data were randomly picked as the training set and others were testing set. Besides, these samples were grouped by age bracket and fitted models as an attempt., Results: Overall, the accuracy of the sex estimation for individuals over 18 years old on the testing set was 77.78%, with a slightly higher accuracy rate for males at 78.12% compared to females at 77.42%. However, accuracy of sex estimation for individuals under 18 was challenging. In comparison to logistic, KNN and SVM, RF exhibited higher accuracy rates. Moreover, incorporating age as a variable improved the accuracy of sex estimation, particularly in the 18-27 age group, where the accuracy rate increased to 88.46%. Meanwhile, all variables showed a linear correlation with age., Conclusion: The linear measurements of the maxillary sinus could be a valuable tool for sex estimation in individuals aged 18 and over. A robust RF model has been developed for sex estimation within the Han population residing in the northwestern region of China. The accuracy of sex estimation could be higher when age is used as a predictive variable., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: To investigate the application value of combining the Demirjian's method with machine learning algorithms for dental age estimation in northern Chinese Han children and adolescents., Methods: Oral panoramic images of 10 256 Han individuals aged 5 to 24 years in northern China were collected. The development of eight permanent teeth in the left mandibular was classified into different stages using the Demirjian's method. Various machine learning algorithms, including support vector regression (SVR), gradient boosting regression (GBR), linear regression (LR), random forest regression (RFR), and decision tree regression (DTR) were employed. Age estimation models were constructed based on total, female, and male samples respectively using these algorithms. The fitting performance of different machine learning algorithms in these three groups was evaluated., Results: SVR demonstrated superior estimation efficiency among all machine learning models in both total and female samples, while GBR showed the best performance in male samples. The mean absolute error (MAE) of the optimal age estimation model was 1.246 3, 1.281 8 and 1.153 8 years in the total, female and male samples, respectively. The optimal age estimation model exhibited varying levels of accuracy across different age ranges, which provided relatively accurate age estimations in individuals under 18 years old., Conclusions: The machine learning model developed in this study exhibits good age estimation efficiency in northern Chinese Han children and adolescents. However, its performance is not ideal when applied to adult population. To improve the accuracy in age estimation, the other variables can be considered.

Co-separation studies between surnames and Y chromosome genetic markers are beneficial to revealing population migrations, surname origins, population formation histories and forensic familial searching. Genetic distributions of 27 Y-STRs in Chinese four surnames (Li, Lin, Chen and Huang) from Zhanjiang Han population were investigated. Meanwhile, we tried to develop a decision tree model for surname predictions based on Y-STR haplotypes. Allelic frequencies of 27 Y-STRs showed that unique alleles were only observed in a certain surname; besides, some alleles displayed higher frequencies in a certain surname than those in other surnames, implying these alleles might be employed as the useful indicators for surname predictions. Haplotype match probability values of 27 Y-STRs in these surnames revealed that the system could be used as a valuable tool for forensic male identification. The developed decision tree model performed well for the training set with the accuracy of 0.9860 and obtained the relatively high accuracy (>0.70) for surname predictions of the testing set. To sum up, we explored the power of the machine learning to the surname predictions based on obtained Y-STR haplotypes, which showed promising application values in forensic familial searching., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Compound marker consists of two different types of genetic markers, like deletion/insertion polymorphism and single nucleotide polymorphism in the genomic region of 200 bp, and microhaplotype consists of a series of closely linked single nucleotide polymorphisms in a small DNA segment (<300 bp), which show great potential for human identifications and mixture analyses. In this study, we initially selected 23 novel genetic markers comprising 10 microhaplotypes and 13 compound markers according to previously reported single nucleotide polymorphism or deletion/insertion polymorphism loci. Genetic distributions of these 23 loci in different continental populations showed that they could be used as valuable loci for forensic human identification purpose. Besides, high informativeness values (>0.1) were observed in six loci which could be further employed for forensic ancestry analyses. Finally, 18 loci were successfully developed into a multiplex panel and detected by the next generation sequencing (NGS) technology. Further analyses of these 18 loci in the studied Shaanxi Han population showed that 15 loci exhibited relatively high expected heterozygosities (>0.5). Cumulative power of discrimination (0.999 999 999 99 4835) of these 18 loci revealed that the multiplex panel could also be utilized for human identifications in the studied Shaanxi Han population., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Mitochondrial DNA (mtDNA) has been widely employed as one tool for the studies of human migration and phylogenetic evolution owing to the characteristics of its lack of recombination and matrilineal inheritance. In this study, we analyze genetic distributions of 60 mtDNA markers in 126 unrelated individuals of Southern Shaanxi Han population and classify their haplogroups. Genetic distribution comparisons between Southern Shaanxi Han and other populations from different continents are conducted based on the same mtDNA markers. The majority of 60 mtDNA markers are polymorphic in Southern Shaanxi Han population. The most common haplogroups observed in Southern Shaanxi Han population are B5, followed by D5, A, D4e, and N9a1'3. Obtained matching probability for these 60 mtDNA markers indicates that the panel could be used as a valuable tool in forensic caseworks. Results of genetic distances (Fst) and multidimensional scaling analysis show that Southern Shaanxi Han population has relatively close genetic relationships with other Han populations in different regions. In conclusion, the panel comprising 60 mtDNA markers could be utilized for forensic applications in Southern Shaanxi Han population.

Tibetans living in the Qing-Tibet plateau show unique genetic features since they are exposed to the high altitude environment. Accordingly, it is necessary for us to analyze genetic components of the Tibetan groups. Here, genetic structure and ancestry proportions of Tibet Tibetan and Qinghai Tibetan groups are dissected by using a previously published ancestral deletion/insertion polymorphisms (DIPs) panel. Genetic distributions of the analyzed DIPs in both Tibetan groups reveal that some DIPs show relatively balanced frequency distributions with the values ranging from 0.4 to 0.6, implying that these DIPs could be used as individual identification loci for forensic applications in both groups. Besides, the cumulative power of discrimination of the panel also reflects that the panel could serve as a valuable tool for forensic individual identifications in Tibet Tibetan and Qinghai Tibetan groups. Population genetic analyses including principal component analysis, D A genetic distances, phylogenetic tree, and genetic structure reveal that two studied Tibetan groups have closer genetic affiliations with East Asian populations. Genetic differentiation analyses of two Han populations, Xinjiang Uyghur and two Tibetan groups reveal that some DIP loci might be informative for differentiating Uyghurs from the other populations.

To further enrich the genetic data of the Chinese Xinjiang Mongolian group, the genetic distribution and forensic parameters of 19 autosomal short tandem repeats (STRs) were investigated. Altogether, 249 alleles were observed in these 19 STRs. The mean values of the polymorphism information content (PIC), match probability (MP), discrimination power (DP), and probability of exclusion (PE) for these 19 STRs were 0.7775, 0.0699, 0.9301, and 0.6085, respectively. Additionally, the cumulative DP and PE values obtained in the Mongolian group were 0.999 999 999 999 999 999 999 995 67 and 0.999 999 992 163, respectively. Furthermore, population genetic analysis of the Mongolian group and 20 published populations was conducted based on the population data of 15 overlapping STRs. Genetic distances indicated that the Mongolian group had closer genetic similarities with the Uyghur, Xibe, and other Chinese populations rather than the other continental populations. Multidimensional scaling analysis further revealed that the Mongolian group possessed similar genetic distributions as most Chinese populations. To sum it all up, these STRs could be used as an extremely efficient tool for forensic applications in the Xinjiang Mongolian group.

Genetic polymorphism analysis of 60 mitochondrial DNA (mtDNA) loci in Chinese Xinjiang Kazak group was conducted in this study. Blood samples from 141 unrelated healthy volunteers were randomly collected from Chinese Kazak ethnic group in Ili, Xinjiang Uygur Autonomous region. Among these mtDNA loci, single nucleotide transition was the most commonly observed variant (87.93%). A total of 25 haplogroups and 79 haplotypes were found in Kazak group, and Haplogroup D4 was the most common haplogroup (21.28%). Among the entire 79 haplotypes, 53 of them were observed for only once, 14 for twice. The haplotype diversity was 0.978 ± 0.005, and the nucleotide diversity was 0.17449. The detection of (CA) n and 9-bp deletion polymorphisms could improve the discrimination power of the mtDNA genetic marker. Moreover, Xinjiang Kazak group was compared with other previously reported groups to infer its genetic background. The present results revealed that Xinjiang Kazak ethnic group was genetically closer related to Xinjiang Uygur, Xinjiang Uzbek and Xinjiang Han populations. Meanwhile, our results also indicated the potential closer genetic relationships among Xinjiang Kazak group with Altaian Kazak as well as Xinjiang Xibe group. In conclusion, this novel mtDNA panel could be effectively utilized for forensic applications. Additionally, to further reveal the genetic background of Chinese Kazak group, more relevant populations and genetic markers should be incorporated in our future study.

Killer cell immunoglobulin like receptor genes expressed by the natural killer cells and T cells of some subclasses are one of the very diversity and complex gene families on chromosome 19q13.4 which play key developmental role in the fight against viral infections, malignantly transformed cells and so on in the first line. As potential markers, KIRs have received more and more attention for some infections and diseases which have some clinical outcomes. In addition, the KIRs are diverse in different populations due to the distinctive alleles and haplotypes, may contribute to understand the genetic relationships among populations. To data, there is no report on the KIR gene polymorphism of the Kirgiz ethnic minority. The purpose of this paper is to determine the KIR gene diversity: KIR gene presence/absence polymorphisms, haplotype/genotype polymorphisms and these polymorphisms between populations distributed worldwide. In this study, we have genotyped the 19 KIR genes: KIR2DL1-4, 2DL5A, 2DL5B, 2DS1-3, 2DS4*FUL, 2DS4*DEL, 2DS5, 3DL1-3, 3DS1, 2DP1, 3DP1*FUL and 3DP1*DEL, and two unique genotypes are found in two Kirgiz individuals. The PCA plot, Neighbor-Joining tree analysis and MDS plot are conducted and the groups of the same language family gather together basically. KIR gene diversity study of populations distributed in different parts of the world. shows that KIRs can be used as a supplement for human genetic researches.

Thirty insertion/deletion loci were utilized to study the genetic diversities of 125 bloodstain samples collected from Bai group in Yunnan Dali region, China. The observed heterozygosity and expected heterozygosity of the 30 loci ranged from 0.1520 to 0.5680, and 0.1927 to 0.4997, respectively. No deviations from Hardy-Weinberg equilibrium tests after Bonferroni correction were found at all 30 loci in Bai group. The cumulative probability of exclusion and combined discrimination power were 0.9859 and 0.9999999999887, respectively, which indicated the 30 loci could be used as complementary genetic markers for paternity testing and were qualified for personal identification in forensic cases. We found the studied Bai group had close relationships with Tibetan, Yi and Han groups from China by the population structure, principal component analysis, population differentiations, and phylogenetic reconstruction studies. Even so, for a better understanding of Bai ethnicity's genetic milieu, DNA genotyping at various genetic markers is necessary in future studies.

Objectives: To study the genetic polymorphisms of 30 insertion/deletion （InDel） loci and evaluate their forensic application in Ewenki ethnic group from Inner Mongolia., Methods: Peripheral blood samples were collected from 87 unrelated healthy individuals in Ewenki ethnic group. Genomic DNA were extracted, and 30 InDel loci of the samples were multiplex amplified and genotyped. Hardy-Weinberg balance tests were preformed for all loci and genetic parameters were calculated by modified PowerStats v1.2 software. The linkage disequilibrium between loci were tested by SNPAnalyzer v2.0 software. Based on the allele frequencies of 30 InDel loci, the genetic relationships between Ewenki ethnic group and other populations were evaluated by analysis of molecular variance, principal component analysis and phylogenetic reconstruction., Results: After correction, 30 InDel loci conformed to Hardy-Weinberg equilibrium. It was found that the pairwise InDel loci were in linkage equilibrium after Bonferroni correction. The results of population genetics indicated that Ewenki ethnic group had close genetic relationships with Henan Han and Beijing Han populations; whereas it was significantly different from several populations in Europe and Mexico., Conclusions: There are relatively high genetic polymorphisms on 30 InDel loci of Ewenki ethnic group from Inner Mongolia, which can be used as a helpful supplement application for STR detection system., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Forensic Medicine)

X-chromosomal short tandem repeats (X-STRs) have been widely used in forensic practices involving complicated ties of kinship over the past years, and also play an increasingly important role in population genetics. To study the genetic polymorphisms of 19 STR loci on X chromosome in Chinese Kazak ethnic group, we investigated the allelic and haplotypic frequencies of the 19 loci in 300 (149 males and 151 females) unrelated healthy individuals from Ili Kazak Autonomous Prefecture, Xinjiang Uigur Autonomous Region of China after having evaluated the forensic application value of these loci in forensic sciences, and then compared the population distinctions between the Kazak group and other reference groups. We observed a total of 240 alleles at these X-STR loci with the corresponding allelic frequencies ranging from 0.0017 to 0.5917. In the study, the highest polymorphism was found at DXS10135 locus. The combined power of discrimination in females was 0.999999999999999999999985 and in males 0.999999999999968. The present study indicates that the 19 X-STR loci are very useful for both forensic identification cases and kinship analyses involving a female offspring., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The population genetic data and forensic parameters of 19 X-chromosome short tandem repeat (X-STR) loci in Chinese Uygur ethnic minority are presented. These loci were detected in a sample of 233 (94 males and 139 females) unrelated healthy individuals. We observed 238 alleles at the 19 X-STR loci, with the corresponding gene frequencies spanning the range from 0.0021 to 0.5644. After Bonferroni correction (P>0.0026), there were no significant deviations from Hardy-Weinberg equilibrium. The cumulative power of discrimination in females and males, and the probability of exclusion of the 19 X-STR loci were 0.999 999 999 999 999 999 998 091, 0.999 999 999 999 966, and 0.999 999 986 35, respectively. The cumulative mean exclusion chance was 0.999 999 992 849 in deficiency cases, 0.999 999 999 999 628 in normal trios, and 0.999 999 998 722 in duo cases. The high value of the forensic parameters mentioned above revealed that the novel panel of 19 loci had important values for forensic applications in the Uygur group.

Objective: To investigate the gene mutations of CHRNB2 and CHRNA2 in Chinese population with autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE)., Methods: One hundred and six Han nationality patients (74 sporadic and 32 familial) were recruited and studied. Mutational screening was performed by sequencing all the 6 coding exons of the CHRNB2 gene and exons 6 and 7 of the CHRNA2 gene including the donor and acceptor splice sites., Results: The results excluded the involvement of all known published mutations of the CHRNB2 and CHRNA2 genes. However, a novel synonymous mutation c.483C>T (H161H) and a single nucleotide polymorphism (c.1407C>G) of CHRNB2 gene were detected in two ADNFLE sporadic patients respectively. The nucleotide variation H161H was heterozygous and absent in 200 healthy control samples. The mutation was also found in the proband's unaffected mother., Conclusion: Our study suggests that the mutations of CHRNB2 and CHRNA2 genes may be rare in Chinese ADNFLE population. The novel synonymous mutation of H161H has not been reported previously and its impact on the pathogenesis of ADNFLE needs to be further studied.