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Objective To evaluate the genetic polymorphisms and forensic efficiencies of 35 deletion/insertion polymorphism(DIP)loci and explore the genetic structure of the Han population in Shaanxi province.Methods Blood samples of 305 unrelated healthy individuals of the Han population in Shaanxi province were collected.And the allelic frequencies and forensic parameters of 35 DIP loci were calculated and analyzed based on their genotyping results by a self-developed amplification system.The genetic relationship of the Han population in Shaanxi province with the reference populations was explored by molecular variance analyses,phylogenetic tree reconstruction,multidimensional scale analyses,principal component analyses,and STRUCTURE analyses.Results The combined power of discrimination and probability of exclusion of the 35 DIP loci in the Han population in Shaanxi province were 0.999 999 999 999 991 119 and 0.9991,respectively.Population genetic analyses indicated that the Han population in Shaanxi province shared relatively closer genetic relationships with those in other regions of China.Conclusions The 35 DIP loci possessed high polymorphisms and could be used as an effective tool for forensic identification of individuals of the Han population in Shaanxi province.Furthermore,the 35 DIP loci could provide basic data for the genetic analysis of the Han population in Shaanxi province.

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.)

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.

A biogeographic estimate of a certain population can not only discern population substructure in the whole genome association study, but also provide informative clues for forensic investigations when obtained DNA genotypes do not find a match in the available forensic DNA database. In this study, 100 ancestry informative single nucleotide polymorphisms (AISNPs) were first presented to differentiate three continental ancestries (African, East Asian and European). Ultimately, forty-two AISNPs were chosen from the 100 AISNPs. Distinguishing power of the 100 and 42 AISNPs for differentiating continental populations was further evaluated with population cluster analyses. Results indicated both of AISNP sets could efficiently differentiate 11 training populations from the three continents. Further validation of 42 AISNPs in testing population set indicated these 42 AISNPs performed well for ancestry inferences of these testing individuals. Ancestry components of Uyghur group were assessed by comparing with different continental populations based on these 42 AISNPs. Results revealed that East Asian populations contributed more ancestry components to the studied Uyghur group than European populations. In conclusion, our study is expected to provide more AISNP markers and enrich extant reference database., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Insertion and deletion markers (InDels) have gained considerable attentions in population genetics and forensic research. In this study, we investigated genetic distributions of 30 InDels in Gansu Yugur and Guizhou Miao groups and evaluated their forensic application values. Genetic relationship analyses between Gansu Yugur, Guizhou Miao groups and other published populations were conducted based on these 30 InDels. Power of discrimination and power of exclusion in trio and duo cases of 30 InDels ranged from 0.3528 to 0.6247, 0.0937 to 0.1873, and 0.0219 to 0.1247 in Gansu Yugur group; and they ranged from 0.2579 to 0.6247, 0.0671 to 0.1874, and 0.0105 to 0.1247 in Guizhou Miao group. Obtained cumulative power of discrimination values indicated these InDels could be used for forensic individual identifications in both ethnic groups. Principal component analysis and phylogenetic reconstruction revealed that Gansu Yugur and Guizhou Miao groups had close affinities with their neighboring populations. Genetic structure analyses among these populations also indicated that studied Gansu Yugur and Guizhou Miao groups showed similar genetic structure with their neighboring populations. Further analyses of Y-STR, mtDNA, and ancestry informative markers should be conducted to better understand genetic backgrounds of Gansu Yugur and Guizhou Miao groups in the future.

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.

We analyzed the genetic polymorphisms of 54 mitochondrial DNA (mtDNA) variants in Chinese Xibe ethnic minority group. A total of 137 unrelated healthy volunteers from Chinese Xibe group were the objects of our study. Among the selected loci, there were 51 variable positions including transitions and transversions, and single nucleotide transitions were common (83.93%) versus transversions. These variations defined 64 different mtDNA haplotypes exclusive of (CA) n and 9 bp deletion variation. The haplotype diversity and discrimination power in Xibe population were 0.9800 ± 0.004 and 0.9699, respectively. Besides, we compared Xibe group with 18 other populations and reconstructed a phylogenetic tree using Neighbor-Joining method. The result revealed that Xibe group was a close to Xinjiang Han and Yanbian Korean groups. Our data also indicated that Xibe group has a close relationship with Daur and Ewenki groups, which is reflected by the history that Xibe was influenced by Daur and Ewenki groups during the development of these groups. In conclusion, the variants we studied are polymorphic and could be used as informative genetic markers for forensic and population genetic application.