Population genetics and forensic efficiency of twenty-one novel microsatellite loci of Chinese Yi ethnic group

Genetic polymorphism and phylogenetic analyses of 21 non-CODIS STR loci in a Chinese Han population from Shanghai

BACKGROUND

Short tandem repeats (STRs) are essential genetic markers for forensic applications and population estimations; thus the population genetics of STR loci have been extensively studied and discussed.

METHODS

In the present study, we detected 21 autosomal noncombined DNA index system (non-CODIS) STR loci in a Chinese Han population from Shanghai, calculated their forensic parameters and analyzed their genetic relationships with reported reference populations in mainland China.

RESULTS

A total of 173 alleles were observed, with corresponding allele frequencies from 0.0020 to 0.5512. The cumulative power of discrimination (CPD) and the cumulative probability of exclusion (CPE) values of the 21 STR loci were 0.999999999999999999997337058271 and 0.99999953732495, respectively. The results of interpopulation differentiation, phylogenetic, multidimensional scaling, and structure analyses indicated a closer genetic relationship of the studied population with Han populations from other regions of China than with other populations.

CONCLUSIONS

The 21 STR loci exhibited high genetic polymorphism in the studied Shanghai_Han population and could be used for forensic applications and population genetic studies.

Genetic diversity of 23 STR loci in Guangxi Zhuang population and its phylogenetic relationship with 25 other populations

Aim: To estimate genetic diversity of 23 STR loci included in the DNA Typer^TM 25 Kit, and evaluate its effectiveness in forensic application.Subjects and methods: A total of 450 (251 males and 179 females) unrelated healthy individuals from Guangxi Zhuang population were amplified with DNA Typer^TM 25 Kit, isolated by the 3730 Series Genetic Analyzer^TM, and genotyped using the GeneMapper ID-X. Genetic parameters and population relationships were analysed.Results: Allele frequencies ranged from 0.001 to 0.5889. The combined power of discrimination (CPD) and the combined power of exclusion (CPE) of the 23 STR loci were 0.999999999999999999 and 0.999996765, respectively. No deviations from Hardy-Weinberg equilibrium and linkage disequilibrium were observed. Inter-population comparison based on Fst, PCA, genetic distance, phylogenetic trees, and MDS showed that Zhuang population clustered with the populations holding a close geographic distance with Zhuang (Guangdong Han and Hainan Li populations).Conclusions: Our study indicated that the 23 autosomal STR loci included in DNA Typer^TM 25 Kit can be used as forensic tools for individual identification and parentage testing. Moreover, the result of our mass investigation will enrich the forensic database of Chinese populations and serve for further study of the origin of anthropology.

Forensic efficiency estimate and phylogenetic analysis for Chinese Kyrgyz ethnic group revealed by a panel of 21 short tandem repeats

Short tandem repeats (STRs) with a high level of polymorphisms and convenient detection method play an indispensable role in human population and forensic genetics. Recently, we detected the 21 autosomal non-combined DNA index system (non-CODIS) STR loci in a Kyrgyz ethnic group, calculated their forensic parameters and analysed its genetic relationships with reference populations from China. In total, 168 alleles were observed at 21 non-CODIS STRs with corresponding allelic frequencies from 0.0016 to 0.4788. No significant deviations at these STRs were observed from the Hardy-Weinberg equilibrium. The values of cumulative power of discrimination and probability of exclusion for all the 21 non-CODIS STRs were 0.99999999999999999998835 and 0.9999994002, respectively. Furthermore, the analyses of phylogenetic trees, genetic distances and interpopulation differentiations demonstrated that the Kyrgyz group had relatively close genetic relationships with the Uygur and Kazak groups. These 21 non-CODIS STRs were characterized by high genetic diversities in the Kyrgyz group and could be applied as a robust tool for individual identification and kinship testing in forensic sciences.

Genetic diversity and phylogenetic characteristics of Chinese Tibetan and Yi minority ethnic groups revealed by non-CODIS STR markers

Non-CODIS STRs, with high polymorphism and allele frequency difference among ethnically and geographically different populations, play a crucial role in population genetics, molecular anthropology, and human forensics. In this work, 332 unrelated individuals from Sichuan Province (237 Tibetan individuals and 95 Yi individuals) are firstly genotyped with 21 non-CODIS autosomal STRs, and phylogenetic relationships with 26 previously investigated populations (9,444 individuals) are subsequently explored. In the Sichuan Tibetan and Yi, the combined power of discrimination (CPD) values are 0.9999999999999999999 and 0.9999999999999999993, and the combined power of exclusion (CPE) values are 0. 999997 and 0.999999, respectively. Analysis of molecular variance (AMOVA), principal component analysis (PCA), multidimensional scaling plots (MDS) and phylogenetic analysis demonstrated that Sichuan Tibetan has a close genetic relationship with Tibet Tibetan, and Sichuan Yi has a genetic affinity with Yunnan Bai group. Furthermore, significant genetic differences have widely existed between Chinese minorities (most prominently for Tibetan and Kazakh) and Han groups, but no population stratifications rather a homogenous group among Han populations distributed in Northern and Southern China are observed. Aforementioned results suggested that these 21 STRs are highly polymorphic and informative in the Sichuan Tibetan and Yi, which are suitable for population genetics and forensic applications.

Genetic polymorphism of 21 non-CODIS STR loci in Chengdu Han population and its interpopulation analysis between 25 populations in China

AGCU 21+1 STR kit contains 21 non-combined DNA index system (non-CODIS) short tandem repeats (STR) loci and a sex-determining locus amelogenin. In this study, we evaluated the genetic diversity and forensically relevant population statistics of 21 non-CODIS loci in 210 Chinese Han individuals from Chengdu city, Sichuan province, Southwest China. No significant deviations from Hardy-Weinberg equilibrium were observed within the 21 non-CODIS STR loci. The combined power of discrimination (CPD) and combined power of exclusion (CPE) were 0.99999999999999999994278, 0.999999355 respectively. To reveal interpopulation differentiations of mainland population of China, a neighbor-joining (N-J) phylogenetic tree was constructed based on Nei's genetic distances among Chengdu Han and 25 published populations. The phylogenetic analyses indicated that Chengdu Han population keeps a close genetic relationship with other Han populations.

Genetic Diversity and Phylogenetic Differentiation of Southwestern Chinese Han: a comprehensive and comparative analysis on 21 non-CODIS STRs

Short tandem repeats (STRs), with high polymorphism and complex evolution information, play a significant role in genetic association studies like population genetics, molecular anthropology and human forensics. However, human genetic diversity has only been partially sampled and available for Southwest Chinese Han population, as well as the genetic architecture of this population remains uncharacterized. In this work, 368 unrelated Han individuals from Sichuan province were firstly genotyped with 21 non-CODIS autosomal STRs, and phylogenetic relationships along administrative (Han Chinese from different regions) and ethnic divisions (minority ethnic groups) were subsequently investigated. The CMP and CPE were 6.2796 × 10-20 and 0.9999999, respectively. Analysis of molecular variance (AMOVA), principal component analysis (PCA), multidimensional scaling plots (MDS) and phylogenetic analysis consistently demonstrated that the Southwest Han population had a close genetic relationship with the geographically close population (Hunan Han) and kept a distant genetic relationship with some ethnic groups, most prominently for Gansu Yugu and Fujian She. Furthermore, no significant genetic distinction between the Northern Han and Southern Han was observed. Aforementioned results suggested that these 21 STRs are highly polymorphic and informative, which are suitable for human identification and population genetics.

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.

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.

Genetic polymorphism analyses of 30 InDels in Chinese Xibe ethnic group and its population genetic differentiations with other groups

In the present study, we obtained population genetic data and forensic parameters of 30 InDel loci in Chinese Xibe ethnic group from northwestern China and studied the genetic relationships between the studied Xibe group and other reference groups. The observed heterozygosities ranged from 0.1704 at HLD118 locus to 0.5247 at HLD92 locus while the expected heterozygosities ranged from 0.1559 at HLD118 locus to 0.4997 at HLD101 locus. The cumulative power of exclusion and total probability of discrimination power in the studied group were 0.9867 and 0.9999999999902 for the 30 loci, respectively. Analyses of structure, PCA, interpopulation differentiations and phylogenetic tree revealed that the Xibe group had close genetic relationships with South Korean, Beijing Han and Guangdong Han groups. The results indicated that these 30 loci should only be used as a complement for autosomal STRs in paternity cases but could provide an acceptable level of discrimination in forensic identification cases in the studied Xibe group. Further studies should be conducted for better understanding of the Xibe genetic background.

Developmental validation of the AGCU 21+1 STR kit: a novel multiplex assay for forensic application

In this study, we describe the developmental validation assay performed on a novel designed STR multiplex system, AGCU 21+1 STR kit. This kit contains a sex-determining locus amelogenin and 21 noncombined DNA index system STR loci, that are, D6S474, D12ATA63, D22S1045, D10S1248, D1S1677, D11S4463, D1S1627, D3S4529, D2S441, D6S1017, D4S2408, D19S433, D17S1301, D1GATA113, D18S853, D20S482, D14S1434, D9S1122, D2S1776, D10S1435, and D5S2500. The 21+1 kit was validated by a series of tests including optimized PCR conditions, sensitivity, precision and accuracy, stutter ratio, DNA mixture, inhibitors, and species specificity according to the revised validation guidelines issued by the Scientific Working Group on DNA Analysis Methods (SWGDAM). Our results in this study show that the kit is a useful tool for forensic application.

Structural polymorphism analysis of Chinese Mongolian ethnic group revealed by a new STR panel: genetic relationship to other groups

Mongolian is the eighth largest ethnic minority on Chinese population data according to the 2010 census. In the present study, we presented the first report about the allelic frequencies and forensic statistical parameters at the 21 new STRs and analyzed linkage disequilibrium of pairwise loci in the Mongolian ethnic minority, China. Hardy-Weinberg equilibrium tests demonstrated no significant deviations except for the D1S1627 locus. The cumulative power of discrimination and power of exclusion of all the loci are 0.9999999999999999992576 and 0.9999997528, respectively. The results of analysis of molecular variance showed that significant differences between the Mongolian and the other eight populations were found at 1-9 STR loci. In population genetics, the results of principal component analysis, structure analysis, and phylogenetic reconstruction analysis indicated shorter genetic distance between the Mongolian group and the Ningxia Han. All the results suggest that the 21 new STR loci will contribute to Chinese population genetics and forensic caseworks in the Mongolian group.