Population genetic analysis of the GlobalFiler STR loci in 748 individuals from the Kazakh population of Xinjiang in northwest China

Genetic diversity of 15 STR loci in Yunnan Va ethnic minority and the phylogenetic relationships with 26 other populations

BACKGROUND

The Va (also called "Wa") people are an ethnic minority living mainly in the southwest of Yunnan Province.

AIM

This study was conducted to obtain the genetic information and forensic statistical parameters of 15 autosomal short tandem repeat (STR) loci included in the AmpFlSTR^®Identifiler™ kit (Applied Biosystems, Foster City, CA) in the Yunnan Va population, with a view to enriching the genetic databases of the Chinese Va population.

SUBJECTS AND METHODS

A total of 508 unrelated Chinese Va individuals were genotyped with this 15 STR kit, the genetic polymorphisms and associated forensic parameters were calculated. The genetic relationships between Chinese Va and 26 other Chinese populations were also evaluated.

RESULTS

All of the STR loci reached the Hardy-Weinberg equilibrium after Bonferroni correction. A total of 159 alleles were observed with allele frequencies ranging from 0.000984 to 0.606299. The combined discrimination power (CDP) and the cumulative probability of excluding (CPE) of the 15 STR loci were 0.999 999 999 999 999 988 126 and 0.999 995 734, respectively. Our results indicated that the geographically adjacent or ethnically close populations showed a higher genetic affinity.

CONCLUSIONS

The results of this study will enrich the forensic databases of the Chinese Va population and could be applied in forensic analysis.

The Heart of Silk Road "Xinjiang," Its Genetic Portray, and Forensic Parameters Inferred From Autosomal STRs

The Xinjiang Uyghur Autonomous Region of China (XUARC) harbors almost 50 ethnic groups including the Uyghur (UGR: 45.84%), Han (HAN: 40.48%), Kazakh (KZK: 6.50%), Hui (HUI: 4.51%), Kyrgyz (KGZ: 0.86%), Mongol (MGL: 0.81%), Manchu (MCH: 0.11%), and Uzbek (UZK: 0.066%), which make it one of the most colorful regions with abundant cultural and genetic diversities. In our previous study, we established allelic frequency databases for 14 autosomal short tandem repeats (STRs) for four minority populations from XUARC (MCH, KGZ, MGL, and UZK) using the AmpFlSTR® Identifiler PCR Amplification Kit. In this study, we genotyped 2,121 samples using the GoldenEye™ 20A Kit (Beijing PeopleSpot Inc., Beijing, China) amplifying 19 autosomal STR loci for four major ethnic groups (UGR, HAN, KZK, and HUI). These groups make up 97.33% of the total XUARC population. The total number of alleles for all the 19 STRs in these populations ranged from 232 (HAN) to 224 (KZK). We did not observe any departures from the Hardy-Weinberg equilibrium (HWE) in these populations after sequential Bonferroni correction. We did find minimal departure from linkage equilibrium (LE) for a small number of pairwise combinations of loci. The match probabilities for the different populations ranged from 1 in 1.66 × 1023 (HAN) to 6.05 × 1024 (HUI), the combined power of exclusion ranged from 0.999 999 988 (HUI) to 0.999 999 993 (UGR), and the combined power of discrimination ranged from 0.999 999 999 999 999 999 999 983 (HAN) to 0.999 999 999 999 999 999 999 997 (UGR). Genetic distances, principal component analysis (PCA), STRUCTURE analysis, and the phylogenetic tree showed that genetic affinity among studied populations is consistent with linguistic, ethnic, and geographical classifications.

New insights into the fine-scale history of western-eastern admixture of the northwestern Chinese population in the Hexi Corridor via genome-wide genetic legacy

Trans-Eurasian cultural and genetic exchanges have significantly influenced the demographic dynamics of Eurasian populations. The Hexi Corridor, located along the southeastern edge of the Eurasian steppe, served as an important passage of the ancient Silk Road in Northwest China and intensified the transcontinental exchange and interaction between populations on the Central Plain and in Western Eurasia. Historical and archeological records indicate that the Western Eurasian cultural elements were largely brought into North China via this geographical corridor, but there is debate on the extent to which the spread of barley/wheat agriculture into North China and subsequent Bronze Age cultural and technological mixture/shifts were achieved by the movement of people or dissemination of ideas. Here, we presented higher-resolution genome-wide autosomal and uniparental Y/mtDNA SNP or STR data for 599 northwestern Han Chinese individuals and conducted 2 different comprehensive genetic studies among Neolithic-to-present-day Eurasians. Genetic studies based on lower-resolution STR markers via PCA, STRUCTURE, and phylogenetic trees showed that northwestern Han Chinese individuals had increased genetic homogeneity relative to northern Mongolic/Turkic/Tungusic speakers and Tibeto-Burman groups. The genomic signature constructed based on modern/ancient DNA further illustrated that the primary ancestry of the northwestern Han was derived from northern millet farmer ancestors, which was consistent with the hypothesis of Han origin in North China and more recent northwestward population expansion. This was subsequently confirmed via excess shared derived alleles in f₃/f₄ statistical analyses and by more northern East Asian-related ancestry in the qpAdm/qpGraph models. Interestingly, we identified one western Eurasian admixture signature that was present in northwestern Han but absent from southern Han, with an admixture time dated to approximately 1000 CE (Tang and Song dynasties). Generally, we provided supporting evidence that historic Trans-Eurasian communication was primarily maintained through population movement, not simply cultural diffusion. The observed population dynamics in northwestern Han Chinese not only support the North China origin hypothesis but also reflect the multiple sources of the genetic diversity observed in this population.

Comprehensive analyses for genetic diversities of 19 autosomal STRs in Chinese Kazak group and its phylogenetic relationships with other continental populations

Short tandem repeats (STRs) play an essential role in forensic genetics due to their high degree of polymorphisms, wide distributions and easy detection method. In this study, allelic frequencies and forensic statistical parameters of the 19 autosomal STR loci in a Kazak ethnic group were calculated, and its genetic relationships with reference populations were assessed in order to understand population structure better and enrich population genetic data for forensic practice in Chinese Kazak ethnic group. There were 226 identified alleles with the corresponding allelic frequencies ranging from 0.0008 to 0.5295 in the 628 unrelated healthy Kazak individuals in Xinjiang Uygur Autonomous Region. All autosomal STRs were conformed to the Hardy-Weinberg equilibrium after Bonferroni’s correction. The cumulative power of discrimination and the combined probability of exclusion of all the 19 autosomal STRs were 0.999 999 999 999 999 999 999 997 162 and 0.999 999 994 484, respectively. Furthermore, the D_A distances and Fixation index values of pairwise populations, principal component analysis, multidimensional scaling analysis, phylogenetic tree analysis and structure analysis were conducted to probe the genetic relationships between the Kazak group and other reference populations. The population genetic results showed that these 19 autosomal STR loci were characterised by high genetic diversities in the Kazak group. Furthermore, the studied Kazak group had close genetic relationships with the Uyghur group and the Uzbek group. The present results may facilitate understanding the genetic background of the Chinese Xinjiang Kazak group.

Population genetic analysis of Shaanxi male Han Chinese population reveals genetic differentiation and homogenization of East Asians

BACKGROUND

Shaanxi province, located in the upper Yellow River, has been evidenced as the geographic origin of Chinese civilization, Sino-Tibetan-speaking language, and foxtail or broomcorn millet farmers via the linguistic phylogenetic spectrum, archeological documents, and genetic evidence. Nowadays, Han Chinese is the dominant population in this area. The formation process of modern Shaanxi Han population reconstructed via the ancient DNA is on the way, however, the patterns of genetic relationships of modern Shaanxi Han, allele frequency distributions of high mutated short tandem repeats (STRs) and corresponding forensic parameters are remained to be explored.

METHODS

Here, we successfully genotyped 23 autosomal STRs in 630 unrelated Shaanxi male Han individuals using the recently updated Huaxia Platinum PCR amplification system. Forensic allele frequency and parameters of all autosomal STRs were assessed. And comprehensive population genetic structure was explored via various typical statistical technologies.

RESULTS

Population genetic analysis based on the raw-genotype dataset among 15,803 Eurasian individuals and frequency datasets among 56 populations generally illustrated that linguistic stratification is significantly associated with the genetic substructure of the East Asian population. Principal component analysis, multidimensional scaling plots and phylogenetic tree further demonstrated that Shaanxi Han has a close genetic relationship with geographically close Shanxi Han, and showed that Han Chinese is a homogeneous population during the historic and recent admixture from the STR variations. Except for Sinitic-speaking populations, Shaanxi Han harbored more alleles sharing with Tibeto-Burman-speaking populations than with other reference populations. Focused on the allele frequency correlation and forensic parameters, all loci are in accordance with the minimum requirements of HWE and LD. The observed combined probability of discrimination of 8.2201E-28 and the cumulative power of exclusion of 0.9999999995 in Shaanxi Han demonstrated that the studied STR loci are informative and polymorphic, and this system can be used as a powerful routine forensic tool in personal identification and parentage testing.

CONCLUSION

Both the geographical and linguistic divisions have shaped the genetic structure of modern East Asian. And more forensic reference data should be obtained for ethnically, culturally, geographically and linguistically different populations for better routine forensic practice and population genetic studies.

Population data of 21 autosomal STR loci in Malaysian populations for human identification

The use of 21 autosomal STR loci for human identification has been gaining popularity throughout the world. It has been indicated that the forensic statistical parameters for supporting the use of 21 STR loci varied among different populations. Hitherto, such data for the diverse Malaysian populations remain unreported, rendering doubts in the court of law about its real ability for human identification in Malaysian population. Using the GlobalFiler™ Express PCR Amplification Kit, complete DNA profiles of 21 STR loci from buccal swabs of convicted Malaysian criminal (n = 570; 190 each for Malays, Chinese, and Indians) (by the year 2016-2017) were analyzed for their allele frequencies, exact test of Hardy-Weinberg equilibrium, observed and expected heterozygosity, power of discrimination, power of exclusion, match probability, and polymorphism information content. Most of the loci were found to be in the Hardy-Weinberg equilibrium after the Bonferroni correction. Being the most informative locus, SE33 demonstrated the highest power of discrimination and power of exclusion, indicating its usefulness to discriminate individuals. In contrast, TPOX had the lowest power of discrimination and power of exclusion, as well as being the less informative genetic locus for all Malaysian population studied here. The probabilities that two individuals would share the same DNA profiles among the Malaysian Malays, Chinese, and Indians, as well as in general Malaysian population, were 1.3713 × 10^-25, 2.8822 × 10^-25, 7.5668 × 10^-26, and 1.0385 × 10^-26, respectively. The results obtained here were found comparable with similar studies reported in other populations. Hence, its robustness for forensic human identification among the Malaysian populations is, therefore, statistically supported.

Population Genetic Analysis of Modern and Ancient DNA Variations Yields New Insights Into the Formation, Genetic Structure, and Phylogenetic Relationship of Northern Han Chinese

Modern East Asians derived from the admixture of aborigines and incoming farmers expanding from Yellow and Yangtze River Basins. Distinct genetic differentiation and subsequent admixture between Northeast Asians and Southeast Asians subsequently evidenced by the mitochondrial DNA, Y-chromosomal variations, and autosomal SNPs. Recently, population geneticists have paid more attention to the genetic polymorphisms and background of southern-Han Chinese and southern native populations. The genetic legacy of northern-Han remains uncharacterized. Thus, we performed this comprehensive population genetic analyses of modern and ancient genetic variations aiming to yield new insight into the formation of modern Han, and the genetic ancestry and phylogenetic relationship of the northern-Han Chinese population. We first genotyped 25 forensic associated markers in 3,089 northern-Han Chinese individuals using the new-generation of the Huaxia Platinum System. And then we performed the first meta-analysis focused on the genetic affinity between Asian Neolithic∼Iron Age ancients and modern northern-Han Chinese by combining mitochondrial variations in 417 ancient individuals from 13 different archeological sites and 812 modern individuals, as well as Y-chromosomal variations in 114 ancient individuals from 12 Neolithic∼Iron Age sites and 2,810 modern subjects. We finally genotyped 643,897 genome-wide nucleotide polymorphisms (SNPs) in 20 Shanxi Han individuals and combined with 1,927 modern humans and 40 Eurasian ancient genomes to explore the genetic structure and admixture of northern-Han Chinese. We addressed genetic legacy, population structure and phylogenetic relationship of northern-Han Chinese via various analyses. Our population genetic results from five different reference datasets indicated that Shanxi Han shares a closer phylogenetic relationship with northern-neighbors and southern ethnically close groups than with Uyghur and Tibetan. Genome-wide variations revealed that modern northern-Han derived their ancestry from Yakut-related population (25.2%) and She-related population (74.8%). Summarily, the genetic mixing that led to the emergence of a Han Chinese ethnicity occurred at a very early period, probably in Neolithic times, and this mixing involved an ancient Tibeto-Burman population and a local pre-Sinitic population, which may have been linguistically Altaic.

Forensic characteristics and population genetics of Chinese Kazakh ethnic minority with an efficient STR panel

On the purpose of enhancing the forensic efficiency of CODIS STR loci, new STR loci have been gradually discovered and developed into some commercial multiplex systems. Recently, 22 STR loci including 18 non-CODIS STR loci and four CODIS STR loci were investigated in 501 unrelated healthy individuals of Kazakh ethnic group. Seven to 20 alleles at the different loci were identified and altogether 276 alleles for 22 selected loci were detected with the corresponding allelic frequencies ranging from 0.0010 to 0.3623. No significant deviation was observed from the Hardy-Weinberg equilibrium test for any of the 22 STRs. The value of cumulative power of discrimination in Kazakh group was 1-1.00E^-28. Analyses of population differentiations and genetic distances between Kazakh and other Chinese groups presented that the Kazakh group with the Uygur group. These 22 STR loci evenly distributed on 22 different autosomal chromosomes were characterized by high genetic diversities and therefore could be utilized in the forensic cases to further increase the discrimination performance.

Genetic polymorphism and phylogenetic differentiation of the Huaxia Platinum System in three Chinese minority ethnicities

Short tandem repeats (STRs) with features of high polymorphism and abundant evolution information play a significant role in genetic applications such as human forensics, anthropology and population genetics. The Huaxia Platinum System was specifically exploited to allow coamplification of all markers in the expanded Combined DNA Index System and the Chinese National Database. Herein, in continuation of our previous studies, 493 unrelated individuals were firstly genotyped to investigate the efficacy of this novel system in three minority ethnicities of China (Hui, Tibetan and Uygur). Additionally, genetic relationships among our three investigated populations and other previously published populations were analyzed using pairwise genetic distances, multidimensional scaling (MDS), principal component analysis (PCA), cladogram and STRUCTURE. The combined match probabilities (CMP) for the Hui, Tibetan and Uygur groups were 1.6894 × 10⁻²⁷, 6.1666 × 10⁻²⁷ and 5.0655 × 10⁻²⁷, respectively, and the combined powers of exclusion (CPE) were 0.999999999646627, 0.999999999304935 and 0.999999999433994. Population comparison analysis manifested that the Hui and Tibetan populations had genetic affinities with the Han, Yi and Korean populations, while the Uygur group had a close relationship with the Kazakh population. The aforementioned results suggested that the Huaxia Platinum System is a polymorphic and effective tool that is appropriate for personal identification and population genetics.

Forensic characterization of 15 autosomal STRs in four populations from Xinjiang, China, and genetic relationships with neighboring populations

The Xinjiang Uyghur Autonomous Region of China (XUARC) harbors 47 ethnic groups including the Manchu (MCH: 0.11%), Mongols (MGL: 0.81%), Kyrgyz (KGZ: 0.86%) and Uzbek (UZK: 0.066%). To establish DNA databases for these populations, allele frequency distributions for 15 autosomal short tandem repeat (STR) loci were determined using the AmpFlSTR Identifiler PCR amplification kit. There was no evidence of departures from Hardy–Weinberg equilibrium (HWE) in any of the four populations and minimal departure from linkage equilibrium (LE) for a very small number of pairwise combinations of loci. The probabilities of identity for the different populations ranged from 1 in 1.51 × 10¹⁷ (MCH) to 1 in 9.94 × 10¹⁸ (MGL), the combined powers of discrimination ranged from 0.99999999999999999824 (UZK) to 0.9999999999999999848 (MCH) and the combined probabilities of paternal exclusion ranged from 0.9999979323 (UZK) to 0.9999994839 (MCH). Genetic distances, a phylogenetic tree and principal component analysis (PCA) revealed that the MCH, KGZ and UZK are genetically closer to the Han population of Liaoning and the Mongol population of Mongolia while the MGL are closer to Han, Japanese, Korean, Malaysian, Hong Kong Han and Russians living in China.

Population data and phylogenetic structure of Han population from Jiangsu province of China on GlobalFiler STR loci

Forensic statistical parameters based on allelic frequencies of commonly used short tandem repeats were estimated for the Han population of Jiangsu province from P.R. China. The 6-dye GlobalFiler™ PCR amplification kit incorporates 21 autosomal STRs, providing reliable DNA typing results with enhanced the power of discrimination. Here, we analyzed the GlobalFiler™ STR loci in 516 unrelated individuals from Jiangsu Han population. A total of 256 alleles were observed ranging between 5 and 35.2 repeat units, and SE33 showed the greatest power of discrimination (34 alleles) in Jiangsu Han population. Most of the loci were found to be in the Hardy-Weinberg equilibrium after the Bonferroni correction with the exception of D3S1358. The combined power of exclusion (CPE) was 0.999999996353609, and the combined match probability (CMP) was 3.64 × 10^-25. Phylogenetic parameters including pairwise genetic distances showed that Han population living in Jiangsu had closest genetic relationship with other East Asian populations. The present study provides precise reference database for forensic applications and population genetic studies.