Y-chromosome polymorphisms and ethnic group - a combined STR and SNP approach in a population sample from northern Italy

Forensic Analysis and Genetic Structure Construction of Chinese Chongming Island Han Based on Y Chromosome STRs and SNPs

Y-chromosome short tandem repeat (Y-STR) and Y-chromosome single nucleotide polymorphism (Y-SNP) are genetic markers on the male Y chromosome for individual identification, forensic applications, and paternal genetic history analysis. In this study we successfully genotyped 38 Y-STR loci and 24 Y-SNP loci of Pudong Han (n = 689) and Chongming Han (n = 530) in Shanghai. The haplotype diversity of the Y filer platinum genotyping system was the highest in the Han population in the Pudong area of Shanghai (0.99996) and Chongming Island (0.99997). The proportion of unique haplotypes was 97.10% (Pudong) and 98.49% (Chongming), respectively. The multidimensional scaling analysis and phylogenetic analysis were performed according to the genetic distance Rst, which was calculated based on the Y-STR gene frequency data. Moreover, we made a comparison on the frequency distribution analysis and principal component analysis of haplogroups in both populations. As a result, Shanghai Pudong Han, Chongming Island Han, and Jiangsu Han were determined to have a strong genetic affinity. The haplogroup distribution characteristics of the Pudong Han and Chongming Han populations were similar to those of the southern Han population. The results of haplotype network analysis showed that Jiangsu Wujiang Han and Jiangsu Changshu Han had more paternal genetic contributions to the formation of Shanghai Pudong Han and Chongming Island Han. Through the joint analysis of SNPs and STRs, this study deeply analyzed the paternal genetic structure of the Pudong Han and Chongming Han populations. The addition of Y-SNP haplogroups to forensic applications can provide information for pedigree investigation.

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.