A Bibliometric and Visual Analysis of the Current Status and Trends of Forensic Mixed Stain Research.

OBJECTIVES: To explore the context and hotspot changes of forensic mixed stain research through bibliometric approach. METHODS: The literature of forensic mixed stain included in the core collection of Web of Science database from 2011 to 2022 were collected as the study object, and the annual publication number, countrie (region), institution, journal, keywords, etc. were bibliometrically and visually analyzed using the R-based Bibliometrix 1.1.6 package and VOSviewer 1.6.18 software. RESULTS: A total of 732 articles on forensic mixed stain were included from 2011 to 2022, with the annual number of articles published and the annual citation frequency showing a steady increase year by year. Among the 59 countries (regions) with the most published articles, the United States ranked first with 246 articles, followed by China with 153 articles. The literature came from 104 journals, and the total number of articles published in the top 10 journals was 633. FORENSIC SCI INT GENET ranked first with 307 articles. Visual analysis using VOSviewer software showed that keywords could be divided into four research clusters, namely the genetic marker development group (blue), the mixed stain typing analysis theory group (red), the sequencing analysis group (yellow), and the case sample research group (green). It can be divided into four development stages in terms of different time periods: early development (2011-2013), middle development (2014-2016), rapid development (2017-2020) and latest development (2021-2022). CONCLUSIONS: The number of publications by domestic and foreign scholars in the study of mixed stain in forensic science is showing a relatively stable trend. Machine learning, next generation sequencing and other research have been the hottest topics that have attracted the most attention in recent years, which is expected to further develop the theory of mixed stain typing and sequencing analysis in forensic mixed stain research.

The Latest Research Progress on Cell-Free DNA and Prospects of Its Forensic Application.

In recent years, with the continuous progress of DNA extraction and detection technology, cell-free DNA(cfDNA)has been widely used in the life science field, and its potential application value in forensic identification is becoming more and more obvious. This paper reviews the concept, formation mechanism, and classification of cfDNA, etc., and describes the latest research progress of cfDNA in personal identification of crime scene touch DNA samples and non-invasive prenatal paternity testing (NIPPT). Meanwhile, this paper summarizes the potential application of cfDNA in injury inference, and discusses the advantages and disadvantages of common cfDNA analysis methods and techniques, and its application prospects, to provide a new idea for the wide application of cfDNA in the field of forensic science.

Exploration and Practice of the "One Combination, Two Highlights, Three Combinations, Four in One" Innovative Talents Training Mode in Forensic Medicine.

Talent is one of the basic and strategic supports for building a modern socialist country in all aspects. Since the 1980s, the establishment of forensic medicine major and the cultivation of innovative talents in forensic medicine have become hot topics in higher education in forensic medicine. Over the past 43 years, the forensic medicine team of Shanxi Medical University has adhered to the joint education of public security and colleges, and made collaborative innovation, forming a training mode of "One Combination, Two Highlights, Three Combinations, Four in One" for innovative talents in forensic medicine. It has carried out "5+3/X" integrated reform, and formed a relatively complete talent training innovation mode and management system in teaching, scientific research, identification, major, discipline, team, platform and cultural construction. It has made a historic contribution to China's higher forensic education, accumulated valuable experience for the construction of first-class major and first-class discipline of forensic medicine, and provided strong support for the construction of the national new forensic talent training system. The popularization of this training mode is conducive to the rapid and sustainable development of forensic science, and provides more excellent forensic talents for national building, regional social development and the discipline construction of forensic science.

Actual mutational research of 19 autosomal STRs based on restricted mutation model and big data.

Short tandem repeat (STR) markers have been widely used in forensic paternity testing and individual identification, but the STR mutation might impact on the forensic result interpretation. Importantly, the STR mutation rate was underestimated due to ignoring the "hidden" mutation phenomenon in most similar studies. Considering this, we use Slooten and Ricciardi's restricted mutation model based on big data to obtain more accurate mutation rates for each marker. In this paper, the mutations of 20 autosomal STRs loci (D3S1358, D1S1656, D13S317, Penta E, D16S539, D18S51, D2S1338, CSF1PO, Penta D, TH01, vWA, D21S11, D6S1043, D7S820, D5S818, TPOX, D8S1179, D12S391, D19S433, and FGA; The restricted model does not include the correction factor of D6S1043, this paper calculates remaining 19 STR loci mutation rates) were investigated in 28,313 (Total: 78,739 individuals) confirmed parentage-testing cases in Chinese Han population. As a result, total 1665 mutations were found in all loci, including 1614 one-steps, 34 two-steps, 8 three-steps, and 9 nonintegral mutations. The loci-specific average mutation rates ranged from 0.00007700 (TPOX) to 0.00459050 (FGA) in trio's and 0.00000000 (TPOX) to 0.00344850 (FGA) in duo's. We analyzed the relationship between mutation rates of the apparent and actual, the trio's and duo's, the paternal and maternal, respectively. The results demonstrated that the actual mutation rates are more than the apparent mostly, and the values of µ1"/µ2"(apparent) are also greater than µ1/µ2 (actual) commonly (µ1", µ1; µ2", µ2 are the mutation rates of one-step and two-step). Therefore, the "hidden" mutations are identified. In addition, the mutations rates of trio's and duo's, the paternal and maternal, exhibit significant difference. Next, those mutation data are used to do a comparison with the studies of other Han populations in China, which present the temporal and regional disparities. Due to the large sample size, some rare mutation events, such as monozygotic (MZ) mutation and "fake four-step mutation", are also reported in this study. In conclusion, the estimation values of actual mutations are obtained based on big data, they can not only provide basic data for the Chinese forensic DNA and population genetics databases, but also have important significance for the development of forensic individual identification, paternity testing and genetics research.

Forensic nanopore sequencing of STRs and SNPs using Verogen's ForenSeq DNA Signature Prep Kit and MinION.

The MinION nanopore sequencing device (Oxford Nanopore Technologies, Oxford, UK) is the smallest commercially available sequencer and can be used outside of conventional laboratories. The use of the MinION for forensic applications, however, is hindered by the high error rate of nanopore sequencing. One approach to solving this problem is to identify forensic genetic markers that can consistently be typed correctly based on nanopore sequencing. In this pilot study, we explored the use of nanopore sequencing for single nucleotide polymorphism (SNP) and short tandem repeat (STR) profiling using Verogen's (San Diego, CA, USA) ForenSeq DNA Signature Prep Kit. Thirty single-contributor samples and DNA standard material 2800 M were genotyped using the Illumina (San Diego, CA, USA) MiSeq FGx and MinION (with R9.4.1 flow cells) devices. With an optimized cutoff for allelic imbalance, all 94 identity-informative SNP loci could be genotyped reliably using the MinION device, with an overall accuracy of 99.958% (1 error among 2926 genotypes). STR typing was notably error prone, and its accuracy was locus dependent. We developed a custom-made bioinformatics workflow, and finally selected 13 autosomal STRs, 14 Y-STRs, and 4 X-STRs showing high consistency between nanopore and Illumina sequencing among the tested samples. These SNP and STR loci could be candidates for panel design for forensic analysis based on nanopore sequencing.

Development of a massively parallel sequencing assay for investigating sequence polymorphisms of 15 short tandem repeats in a Chinese Northern Han population.

Massively parallel sequencing (MPS) has been used in forensic genetics in recent years owing to several advantages, e.g. MPS can provide precise descriptions of the repeat allele structure and variation in the repeat-flanking regions, increasing the discriminating power among loci and individuals. However, it cannot be fully utilized unless sufficient population data are available for all loci. Thus, there is a pressing need to perform population studies providing a basis for the introduction of MPS into forensic practice. Here, we constructed a multiplex PCR system with fusion primers for one-directional PCR for MPS of 15 commonly used forensic autosomal STRs and amelogenin. Samples from 554 unrelated Chinese Northern Han individuals were typed using this MPS assay. In total, 313 alleles obtained by MPS for all 15 STRs were observed, and the corresponding allele frequencies ranged between 0.0009 and 0.5162. Of all 15 loci, the number of alleles identified for 12 loci increased compared to capillary electrophoresis approaches, and for the following six loci more than double the number of alleles was found: D2S1338, D5S818, D21S11, D13S317, vWA, and D3S1358. Forensic parameters were calculated based on length and sequence-based alleles. D21S11 showed the highest heterozygosity (0.8791), discrimination power (0.9865), and paternity exclusion probability in trios (0.7529). The cumulative match probability for MPS was approximately 2.3157 × 10-20 .

A 472-SNP panel for pairwise kinship testing of second-degree relatives.

Kinship testing based on genetic markers, as forensic short tandem repeats (STRs) and single nucleotide polymorphisms (SNPs), has valuable practical applications. Paternity and first-degree relationship can be accurately identified by current commonly-used forensic STRs and reported SNP markers. However, second-degree and more distant relationships remain challenging. Although ∼105-106 SNPs can be used to estimate relatedness of higher degrees, genome-wide genotyping and analysis may be impractical for forensic use. With rapid growth of human genome data sets, it is worthwhile to explore additional markers, especially SNPs, for kinship analysis. Here, we reported an autosomal SNP panel consisted of 342 SNP selected from >84 million SNPs and 131 SNPs from previous systems. We genotyped these SNPs in 136 Chinese individuals by multiplex amplicon Massively Parallel Sequencing, and performed pairwise gender-independent kinship testing. The specificity and sensitivity of these SNPs to distinguish second-degree relatives and the unrelated was 99.9% and 100%, respectively, compared with 53.7% and 99.9% of 19 commonly-used forensic STRs. Moreover, the specificity increased to 100% by the combined use of these STRs and SNPs. The 472-SNP panel could also greatly facilitate the discrimination among different relationships. We estimated that the power of ∼6.45 SNPs were equivalent to one forensic STR in the scenario of 2nd-degree relative pedigree. Altogether, we proposed a panel of 472 SNP markers for kinship analysis, which could be important supplementary of current forensic STRs to solve the problem of second-degree relative testing.

Inferring Chinese surnames with Y-STR profiles.

Co-ancestry of human surnames and Y-chromosomes in most human populations and social groups suggests the possibility of inferring one from the other. However, such an intuitive perspective remains to be formally explored. In the present study, we develop two computational methods, based on cosine distance (dcos) and coalescence distance (dcoal) respectively, to infer surnames from Y-STR profiles. We also survey Y-STR variations at 15 loci for 19,009 individuals of Shandong Province in China. For a total of 266 surnames included in the data set, our methods can pinpoint to a single surname with an average accuracy of 65%, and with an average accuracy higher than 80% when providing >4 candidate surnames. We also demonstrate that increasing the sample size of surnames and the number of STR loci improves the accuracy of surname inference. Our results indicate that the 15 non-duplicated Y-STR loci contain information from which surname can be reliably inferred for Chinese populations, showing a promising application in forensics.

Genetic variation and forensic efficiency of autosomal insertion/deletion polymorphisms in Chinese Bai ethnic group: phylogenetic analysis to other populations.

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.

Chinese Xibe population genetic composition according to linkage groups of X-chromosomal STRs: population genetic variability and interpopulation comparisons.

BACKGROUND: The Xibe population is one of China's officially recognised populations and is now distributed separately from west to east in the northern part of China. X-chromosomal short tandem repeats have a special inheritance pattern, and could be used as complements in forensic application, especially for complex or deficiency cases. SUBJECTS AND METHODS: This study obtained the allelic and haplotypic frequencies of 19 X-STR loci in the Xibe population from Xinjiang Uygur Autonomous Region, China, and studied the genetic differentiations between the Xibe and other populations. RESULTS: The combined power of discrimination in females and males and mean exclusion chances in deficiency cases, normal trios and duo cases was at least 0.999 999 994. In the haplotypic study, the Xibe population showed a more similar pattern of haplotype distribution with Asian populations than populations from other continents, while allelic study also indicated a closer relationship between the Xibe and Asian populations. CONCLUSIONS: The 19 X-STR loci would be useful in forensic application in the studied population. The Xibe population showed a closer genetic relationship with Asian populations in the study, and more population data would be necessary for more detailed genetic relationship studies.

Genetic diversity and haplotypic structure of Chinese Kazak ethnic group revealed by 19 STRs on the X chromosome.

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.

Population genetic structure analysis and forensic evaluation of Xinjiang Uigur ethnic group on genomic deletion and insertion polymorphisms.

BACKGROUND: The Uigur ethnic minority is the largest ethnic group in the Xinjiang Uygur Autonomous Region of China, and valuable resource for the study of ethnogeny. The objective of this study was to estimate the genetic diversities and forensic parameters of 30 insertion-deletion loci in Uigur ethnic group from Xinjiang Uigur Autonomous Region of China and to analyze the genetic relationships between Xinjiang Uigur group and other previously published groups based on population data of these loci. RESULTS: All the tested loci were conformed to Hardy-Weinberg equilibrium after Bonferroni correction. The observed and expected heterozygosity ranged from 0.3750 to 0.5515; and 0.4057 to 0.5037, respectively. The combined power of discrimination and probability of exclusion in the group were 0.99999999999940 and 0.9963, respectively. We analyzed the D A distance, interpopulation differentiations and population structure, conducted principal component analysis and neighbor-joining tree based on our studied group and 21 reference groups. The present results indicated that the studied Xinjiang Uigur group (represented our samples from the whole territory of Xinjiang Uigur Autonomous Region) had a close relationships with Urumchi Uigur (represented previously reported samples from Urumchi of Xinjiang) and Kazak groups. CONCLUSIONS: The present study may provide novel biological information for the study of population genetics, and can also increase our understanding of the genetic relationships between Xinjiang Uigur group and other groups.

Study of genetic diversity of killer cell immunoglobulin-like receptor loci in the Tujia ethnic minority.

The aim of this study was to analyze the genetic profiles of 14 killer cell immunoglobulin-like receptor (KIR) genes and 2 pseudogenes of 124 individuals from Tujia ethnic minority residing in Enshi Tujia and Miao autonomous prefecture of Hubei province of China and investigate the genetic relationships between the Tujia ethnic minority and other reported groups for the first time. Sequence specific primer amplification (PCR-SSP) methods were used to genotype the 14 KIR genes and 2 pseudogenes. The observed carrier frequencies (OF) and the gene frequencies (GF) of the KIR genes were measured. Neighbor-joining (N-J) tree and the principal component analysis (PCA) plot were constructed. All individuals were typed positive for the three framework loci KIR3DL3, 2DL4 and 3DL2, as well as for pseudogene KIR3DP1. The gene frequencies of the other KIR genes ranged from 9% in KIR2DS2 to 98% in KIR2DP1 and KIR3DL1. The present study of the KIR genes may be a powerful tool for enriching the Chinese ethnical gene information resources of the KIR gene pool, as well as for the anthropological research.

Whole genome nucleosome sequencing identifies novel types of forensic markers in degraded DNA samples.

In the case of mass disasters, missing persons and forensic caseworks, highly degraded biological samples are often encountered. It can be a challenge to analyze and interpret the DNA profiles from these samples. Here we provide a new strategy to solve the problem by taking advantage of the intrinsic structural properties of DNA. We have assessed the in vivo positions of more than 35 million putative nucleosome cores in human leukocytes using high-throughput whole genome sequencing, and identified 2,462 single nucleotide variations (SNVs), 128 insertion-deletion polymorphisms (indels). After comparing the sequence reads with 44 STR loci commonly used in forensics, five STRs (TH01, TPOX, D18S51, DYS391, and D10S1248)were matched. We compared these "nucleosome protected STRs" (NPSTRs) with five other non-NPSTRs using mini-STR primer design, real-time PCR, and capillary gel electrophoresis on artificially degraded DNA. Moreover, genotyping performance of the five NPSTRs and five non-NPSTRs was also tested with real casework samples. All results show that loci located in nucleosomes are more likely to be successfully genotyped in degraded samples. In conclusion, after further strict validation, these markers could be incorporated into future forensic and paleontology identification kits, resulting in higher discriminatory power for certain degraded sample types.

Genetic polymorphism analyses of a novel panel of 19 X-STR loci in the Chinese Uygur ethnic minority.

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.

Allele and haplotype diversity of new multiplex of 19 ChrX-STR loci in Han population from Guanzhong region (China).

X-chromosomal short tandem repeats (X-STRs) have been proved to be useful for some deficiency paternity cases in recent years. Here, we studied the genetic polymorphisms of 19 X-STR loci (DXS10148-DXS10135-DXS8378, DXS10159-DXS10162-DXS10164, DXS7132-DXS10079-DXS10074-DXS10075, DXS6809-DXS6789, DXS7424-DXS101, DXS10103-HPRTB-DXS10101 and DXS7423-DXS10134) in 252 male and 222 female individuals from Guanzhong Han population, China. No deviation for all 19 loci was observed from the Hardy-Weinberg equilibrium. The polymorphism information content values of the panel of 19 loci were more than 0.5 with the exception of the locus DXS7423. The combined power of discrimination were 0.9999999999999999999994340 in females and 0.9999999999997662 in males, respectively; and the combined mean exclusion chances were 0.999999993764 in duos and 0.999999999997444 in trios, respectively. The haplotype diversities for all the seven clusters of linked loci were more than 0.9. The results showed that the panel of 19 X-STR loci were powerful for forensic applications in Guanzhong Han population. Locus by locus population comparisons showed significant differences at more than seven loci between Guanzhong Han population and the groups from North America, Europe and Africa.

24 Y-chromosomal STR haplotypic structure for Chinese Kazak ethnic group and its genetic relationships with other groups.

The Kazak ethnic minority is a large ethnic group in the Xinjiang Uygur Autonomous Region of China and is valuable resource for the study of ethnogeny. In the present study, 24 Y-chromosomal short tandem repeat (Y-STR) loci were analyzed in 201 unrelated Kazak male individuals from Ili Kazak Autonomous Prefecture, Xinjiang, China. The gene diversity of the 24 Y-STR loci in the studied Kazak group ranged from 0.0050 to 0.9104. According to haplotypic analysis of the 24 Y-STR loci, 113 different haplotypes were obtained, 96 of which were unique. The haplotype diversity and discrimination capacity in Kazak group were 0.9578 and 0.5622 at 24 STR loci, respectively. The haplotype diversity and discrimination capacity at Y-filer 17 loci, extended 11 loci, and minimal 9 loci were reduced to 0.9274 and 0.4279, 0.8459 and 0.3284, and 0.8354 and 0.2985, respectively, which could indicate that the more loci were detected, the higher forensic efficacy was obtained. We evaluated the application value of the 24 loci in forensic sciences and analyzed interpopulation differentiations by making comparisons between the Kazak1 (represent our samples from Ili Kazak Autonomous Prefecture) group and other 14 groups. The results of pairwise genetic distances, multidimensional scaling plot, and neighbor-joining tree at the same set of 17 Y-filer loci indicated that the Kazak1 group had the closer genetic relationships with Kazak2 (represent samples from the whole territory of Xinjiang Uygur Autonomous Region), Mongolian, and Uygur ethnic groups. The present results may provide useful information for paternal lineages in forensic cases and can also increase our understanding of the genetic relationships between Kazak1 and other groups.

Genetic analysis of 15 mtDNA SNP loci in Chinese Yi ethnic group using SNaPshot minisequencing.

SNaPshot minisequencing is a rapid and robust methodology based on a single base extension with a labeled ddNTP. The present study detected 15 selected SNPs in the mitochondrial DNA (mtDNA) control and coding regions by minisequencing methodology using SNaPshot for forensic purpose. The samples were collected from 99 unrelated individuals of the Yi ethnic minority group in Yunnan Province. We have predominantly found high-frequency transitions (91.7%) and a significantly lower frequency of transversions (8.3%). The nt152, 489, 8701, 10,398, 16,183, and 16,362 loci were highly polymorphic, while the nt231, 473 and 581 loci were not polymorphic in the studied population. Based on these 15 SNPs, a total of 28 mtDNA haplotypes were defined in 99 individuals with the haplotype diversity of 0.9136. Also, we compared the mtDNA sequences of Yi group and other 9 populations worldwide and drew a Neighbor-Joining tree based on the shared 12 mtDNA SNP loci, which demonstrated a close relationship between Yi and Bai groups. In conclusion, the analysis of the 15 selected SNPs increases considerably the discrimination power of mtDNA. Moreover, the SNaPshot minisequencing method could quickly detect mtDNA SNPs, and is economical and sensitive. The set of selected 15 SNPs is highly informative and is capable for anthropology genetic analysis.

[Genetic variability and phylogenetic analysis of 39 short tandem repeat loci in Beijing Han population].

In this study, we studied the genetic polymorphisms of short tandem repeat (STR) loci from 13 CODIS and 26 non-CODIS system in Beijing Han population for the first time, and established a database of 39 STR loci whose forensic parameters were further evaluated. Our results demonstrated no significant deviation from the Hardy-Weinberg equilibrium of 39 STR loci and no pairwise linkage disequilibrium between them. The power of discriminations, expected heterozygosity, polymorphic information content, and power of exclusion of 39 STR loci ranged from 0.7740-0.9818, 0.6000-0.9350, 0.5317-0.9047 and 0.2909-0.8673. The cumulated discrimination power and cumulative probability of exclusion were 0.999999999999999999999999999999999999999964971 and 0.999999999973878, respectively. Moreover, the genetic distance was calculated based on allele frequency and phylogenetic tree was built using STR loci data from Beijing Han and other 11 Chinese ethnic groups.This study provides important basic data for Chinese forensic DNA database and population genetics database, and has important significance in carrying out forensic individual identification, paternity testing, and population genetic study.

Genetic variability and phylogenetic analysis of Han population from Guanzhong region of China based on 21 non-CODIS STR loci.

In the present study, we presented the population genetic data and their forensic parameters of 21 non-CODIS autosomal STR loci in Chinese Guanzhong Han population. A total of 166 alleles were observed with corresponding allelic frequencies ranging from 0.0018 to 0.5564. No STR locus was observed to deviate from the Hardy-Weinberg equilibrium and linkage disequilibriums after applying Bonferroni correction. The cumulative power of discrimination and probability of exclusion of all the 21 STR loci were 0.99999999999999999993814 and 0.999998184, respectively. The results of genetic distances, phylogenetic trees and principal component analysis revealed that the Guanzhong Han population had a closer relationship with Ningxia Han, Tujia and Bai groups than other populations tested. In summary, these 21 STR loci showed a high level of genetic polymorphisms for the Guanzhong Han population and could be used for forensic applications and the studies of population genetics.