Genetic diversity and haplotype structure of 27 Y-STR loci in a Han population from Jining, Shandong province, eastern China

Forensic characteristics of 38 Y-STR loci in the Hui population from Shaanxi Province, Northwest China

In this study, we genotyped 939 unrelated healthy individuals to investigate the genetic polymorphisms of 38 Y chromosome short tandem repeats(Y-STRs) loci included in the Yfiler™ Platinum kit in the Hui population of Shaanxi Province. Comprehensive population comparisons were performed using analysis of molecular variance(AMOVA), multidimensional scaling(MDS), and molecular evolutionary genetics analysis(MEGA) to explore population relationships. The allele frequencies of the single-copy loci ranged from 0.001 to 0.940 (DYS645), while those of the multi-copy loci ranged from 0.001 to 0.138 (DYS527). The highest genetic diversity (GD) value was observed for DYS385 (0.9723), and the lowest for DYS645 (0.1138). A total of 849 distinct haplotypes were identified among the 939 Hui individuals, with 808 (95.2 %) being unique. Haplotype diversity (HD), haplotype match probability, and discriminatory power (DC) in the Shaanxi Hui population were 0.9996, 0.0015, and 0.9041, respectively. Interpopulation comparisons based on Rst genetic distance values, phylogenetic trees, and MDS indicated that the Shaanxi Hui population has a close genetic relationship with the Ningxia Hui, Qinghai Hui, Xinjiang Hui, and Yunnan Hui populations. The population genetic stratification largely coincides with geographic distribution and language families. Our study revealed that the 38 Y-STR loci exhibit high genetic polymorphisms in the Hui population from Shaanxi Province.

Genetic Reconstruction and Forensic Analysis of Chinese Shandong and Yunnan Han Populations by Co-Analyzing Y Chromosomal STRs and SNPs

Y chromosomal short tandem repeats (Y-STRs) have been widely harnessed for forensic applications, such as pedigree source searching from public security databases and male identification from male-female mixed samples. For various populations, databases composed of Y-STR haplotypes have been built to provide investigating leads for solving difficult or cold cases. Recently, the supplementary application of Y chromosomal haplogroup-determining single-nucleotide polymorphisms (SNPs) for forensic purposes was under heated debate. This study provides Y-STR haplotypes for 27 markers typed by the Yfiler™ Plus kit and Y-SNP haplogroups defined by 24 loci within the Y-SNP Pedigree Tagging System for Shandong Han (n = 305) and Yunnan Han (n = 565) populations. The genetic backgrounds of these two populations were explicitly characterized by the analysis of molecular variance (AMOVA) and multi-dimensional scaling (MDS) plots based on 27 Y-STRs. Then, population comparisons were conducted by observing Y-SNP allelic frequencies and Y-SNP haplogroups distribution, estimating forensic parameters, and depicting distribution spectrums of Y-STR alleles in sub-haplogroups. The Y-STR variants, including null alleles, intermedia alleles, and copy number variations (CNVs), were co-listed, and a strong correlation between Y-STR allele variants ("DYS518~.2" alleles) and the Y-SNP haplogroup QR-M45 was observed. A network was reconstructed to illustrate the evolutionary pathway and to figure out the ancestral mutation event. Also, a phylogenetic tree on the individual level was constructed to observe the relevance of the Y-STR haplotypes to the Y-SNP haplogroups. This study provides the evidence that basic genetic backgrounds, which were revealed by both Y-STR and Y-SNP loci, would be useful for uncovering detailed population differences and, more importantly, demonstrates the contributing role of Y-SNPs in population differentiation and male pedigree discrimination.

The construction and application of a new 17-plex Y-STR system using universal fluorescent PCR

Y-chromosomal short tandem repeat (Y-STR) polymorphisms are useful in forensic identification, population genetics, and human structures. However, the current Y-STR systems are limited in discriminating distant relatives in a family with a low discrimination power. Increasing the capacity of detecting Y chromosomal polymorphisms will drastically narrow down the matching number of genealogy populations or pedigrees. In this study, we developed a system containing 17 Y-STRs that are complementary to the current commercially available Y-STR kits. This system was constructed by multiplex PCR with expected sizes of 126-400 bp labeled by different fluorescence molecules (DYS715, DYS709, DYS716, DYS713, and DYS607 labeled by FAM; DYS718, DYS723, DYS708, and DYS714 labeled by JOE; DYS712, DYS717, DYS721, and DYS605 labeled by TAMRA; and DYS719, DYS726, DYS598, and DYS722 labeled by ROX). The system was extensively tested for sensitivity, male specificity, species specificity, mixture, population genetics, and mutation rates following the Scientific Working Group on DNA Analysis Methods (SWGDAM) guidelines. The genetic data were obtained from eight populations with a total of 1260 individuals. Our results showed that all the 17 Y-STRs are human- and male-specific and include only one copy of the Y-chromosome. The 17 Y-STR system detects 143 alleles and has a high discrimination power (0.996031746). Mutation rates were different among the 17 Y-STRs, ranging from 0.30 to 3.03%. In conclusion, our study provides a robust, sensitive, and cost-effective genotyping method for human identification, which will be beneficial for narrowing the search scope when applied to genealogy searching with the Y-STR DNA databank.