Confirmation of Y haplogroup tree topologies with newly suggested Y-SNPs for the C2, O2b and O3a subhaplogroups

Validation of phylogenetic informative Y-InDels in Y-chromosomal haplogroup O-M175

The Y-chromosomal haplogroup tree, which consists of a group of Y-chromosomal loci with phylogenetic information, has been widely applied in anthropology, archaeology and population genetics. With the continuous updating of the phylogenetic structure, Y-chromosomal haplogroup tree provides more information for recalling the biogeographical origin of Y chromosomes. Generally, Y-chromosomal insertion-deletion polymorphisms (Y-InDels) are genetically stable as Y-chromosomal single nucleotide polymorphisms (Y-SNPs), and therefore carry mutations that can accumulate over generations. In this study, potential phylogenetic informative Y-InDels were filtered out in haplogroup O-M175, which is dominant in East Asia, based on population data retrieved from the 1000 Genomes Project. A group of 22 phylogenetic informative Y-InDels were identified and then assigned to their corresponding subclades of haplogroup O-M175, which provided a supplement for the update and application of Y-chromosomal markers. Especially, four Y-InDels were introduced to define subclades determined using a single Y-SNP.

CSYseq: The first Y-chromosome sequencing tool typing a large number of Y-SNPs and Y-STRs to unravel worldwide human population genetics

Male-specific Y-chromosome (chrY) polymorphisms are interesting components of the DNA for population genetics. While single nucleotide polymorphisms (Y-SNPs) indicate distant evolutionary ancestry, short tandem repeats (Y-STRs) are able to identify close familial kinships. Detailed chrY analysis provides thus both biogeographical background information as paternal lineage identification. The rapid advancement of high-throughput massive parallel sequencing (MPS) technology in the past decade has revolutionized genetic research. Using MPS, single-base information of both Y-SNPs as Y-STRs can be analyzed in a single assay typing multiple samples at once. In this study, we present the first extensive chrY-specific targeted resequencing panel, the 'CSYseq', which simultaneously identifies slow mutating Y-SNPs as evolution markers and rapid mutating Y-STRs as patrilineage markers. The panel was validated by paired-end sequencing of 130 males, distributed over 65 deep-rooted pedigrees covering 1,279 generations. The CSYseq successfully targets 15,611 Y-SNPs including 9,014 phylogenetic informative Y-SNPs to identify 1,443 human evolutionary Y-subhaplogroup lineages worldwide. In addition, the CSYseq properly targets 202 Y-STRs, including 81 slow, 68 moderate, 27 fast and 26 rapid mutating Y-STRs to individualize close paternal relatives. The targeted chrY markers cover a high average number of reads (Y-SNP = 717, Y-STR = 150), easy interpretation, powerful discrimination capacity and chrY specificity. The CSYseq is interesting for research on different time scales: to identify evolutionary ancestry, to find distant family and to discriminate closely related males. Therefore, this panel serves as a unique tool valuable for a wide range of genetic-genealogical applications in interdisciplinary research within evolutionary, population, molecular, medical and forensic genetics.

Genetic polymorphisms and phylogenetic analyses of the Ü-Tsang Tibetan from Lhasa based on 30 slowly and moderately mutated Y-STR loci

As a result of the expansion of old Tibet on the Qinghai-Tibet Plateau, Tibetans diverged into three main branches, Ü-Tsang, Amdo, and Kham Tibetan. Ü-Tsang Tibetans are geographically distributed across the wide central and western portions of the Qinghai-Tibet Plateau while Lhasa is the central gathering place for Tibetan culture. The AGCU Y30, a 6-dye fluorescence kit including 30 slowly and moderately mutated Y-STR loci, has been validated for its stability and sensitivity in different biomaterials and diverse Chinese populations (Han and other minorities), and widely used in the practical work of forensic science. However, the 30 Y-STR profiling of Tibetan, especially for Ü-Tsang Tibetan, were insufficient. We utilized the AGCU Y30 to genotype 577 Ü-Tsang Tibetan unrelated males from Lhasa in the Tibet Autonomous Region of China to fill up the full and accurate Y-STR profiles. A total of 552 haplotypes were observed, 536 (97.10%) of which were unique. One hundred and ninety-four alleles were observed at 26 single copy loci and the allelic frequencies ranged from 0.0017 to 0.8180. For the two multi-copy loci DYS385a/b and DYS527a/b, 64 and 36 allelic combinations were observed, respectively. The gene diversity (GD) values ranged from 0.3079 at DYS391 to 0.9142 at DYS385a/b and the overall haplotype diversity (HD) was 0.9998, and its discrimination capacity (DC) was 0.9567. The population genetic analyses demonstrated that Lhasa Ü-Tsang Tibetan had close relationships with other Tibetan populations from Tibet and Qinghai, especially with Ü-Tsang Tibetan. From the perspective of Y haplogroups, the admixture of the southward Qiang people with dominant haplogroup O-M122 and the northward migrations of the initial settlers of East Asia with haplogroup D-M175 hinted the Sino-Tibetan homologous, thus, we could not ignore the gene flows with other Sino-Tibetan populations, especially for Han Chinese, to characterize the forensic genetic landscape of Tibetan.

Forensic characteristics and phylogenetic analyses of one branch of Tai-Kadai language-speaking Hainan Hlai (Ha Hlai) via 23 autosomal STRs included in the Huaxia™ Platinum System

BACKGROUND

Hainan Island, located in the South China Sea and separated from the Leizhou Peninsula by Qiongzhou Strait, is the second largest island after Taiwan in China. With the expansion of Han Chinese and the gradual formation of "South Hlai and North Han", nowadays, Hainan Hlai is the second largest population after Han Chinese in Hainan Island. Ha Hlai, distributed in southwest and southern Hainan Island, is the dominant branch of Hlai and speaks Ha localism.

METHODS

We utilized the Huaxia™ Platinum PCR Amplification System (including 23 autosomal STRs and 2 sex-linked markers) to obtain the first STR profiling batch of 657 Ha Hlai individuals (497 males and 160 females). In order to explore the genetic relationships between the studied Ha Hlai and other reference populations with different language families, population genetic analyses, including PCA, MDS, STRUCTURE, and phylogenetic analysis, were conducted based upon the raw data and allelic frequencies of the polymorphic autosomal STR markers.

RESULTS

In total, 271 distinct alleles were observed at the 23 STR loci. The number of diverse alleles ranged from 7 at TPOX locus to 23 at FGA locus, and the allelic frequencies varied from 0.0008 to 0.5533. In addition, the CPE and CPD were 1-7.39 × 10-10 and 1-3.13 × 10-28 , respectively. The phylogenetic analyses indicated that Ha Hlai is a Tai-Kadai language-speaking and relatively isolated population which has a close genetic and geographical relationship with Hainan Hlai, and M95 is the dominant haplogroup in Ha Hlai (56.18%).

CONCLUSION

The 23 autosomal STR genetic markers were highly polymorphic as well as potentially useful for forensic applications in Hainan Ha Hlai population. The phylogenetic analyses demonstrated that small geographic scale gene flows could not be ignored and the shaping of the unique gene pool for each population was the combination effects of geographic, language, and cultural isolations.

Ancient DNA reveals two paternal lineages C2a1a1b1a/F3830 and C2b1b/F845 in past nomadic peoples distributed on the Mongolian Plateau

OBJECTIVES

Since the third century CE, a series of nomadic tribes have been active on the eastern part of the Mongolian Plateau. Characterizing the genetic compositions of past nomadic people is significant for research on the nomadic cultures of the Eurasian Steppe region. Ancient DNA analysis facilitates a deeper understanding of the relationship between historical and modern nomadic populations.

MATERIALS AND METHODS

Whole-genome shotgun sequencing and capture sequencing of the nonrecombining region of the Y chromosome were performed for six ancient Hg C2/M217 individuals. The individuals were interred at six separate sites on the Mongolian Plateau and represent dates spanning the late Neolithic to Yuan Dynasty (~3,500-700 BP).

RESULTS

After NRY capture sequencing, three of the six ancient samples were attributed to C2b1b/F845 and the other three ancient samples belonged to C2a1a1b1a/F3830. Analysis of whole-genome shotgun sequencing data shows that the ancient C2b1b/F845 individuals are closely related to She, Han and other East Asian populations, while the ancient C2a1a1b1a/F3830 individuals are more similar to modern Northeast Asian peoples, such as the Ulchi and Yakut.

DISCUSSION

Hg C2/M217, widely distributed in the eastern part of the Eurasian continent, was discovered in the ancient Central Steppe and Baikal region. This study shows that there were two important subclades of Hg C2/M217 among the ancient nomadic peoples: C2a1a1b1a/F3830, which has made important genetic contributions to modern Mongolic- and Manchu-speaking populations, and C2b1b/F845, which probably originated in the farming populations of southern East Asia and made certain genetic contributions to past nomadic peoples on the Mongolian Plateau.

Defining Y-SNP variation among the Flemish population (Western Europe) by full genome sequencing

Y-chromosomal single nucleotide polymorphisms (Y-SNPs) represent a powerful tool in forensic research and casework, especially for inferring paternal ancestry of unknown perpetrators and unidentified bodies. However, the wealth of recently discovered Y-SNPs, the 'jungle' of different evolutionary lineage trees and nomenclatures, and the lack of population-wide data of many phylogenetically mapped Y-SNPs, limits the use of Y-SNPs in routine forensic approaches. Recently, a concise reference phylogeny of the human Y chromosome, the 'Minimal Reference Y-tree', was introduced aiming to provide a stable phylogeny with optimal global discrimination capacity by including the most resolving Y-SNPs. Here, we obtained a representative sample of 270 whole-genome sequences (WGS) to grasp the Y-SNP variation within the autochthonous Flemish population (Belgium, Western Europe) according to this reference Y-tree. The high quality of the Y-SNP calling was guaranteed for the WGS sample as well as its representativeness for the Flemish population based on the comparison of the main haplogroup frequencies with those from earlier studies on Flanders and the Netherlands. The 270 Flemish Y chromosomes were assigned to 98 different sub-haplogroups of the Minimal Reference Y-tree, showing its high potential of discrimination and confirming the spectrum of evolutionary lineages within Western Europe in general and within Flanders in particular. The full database with all Y-SNP calls of the Flemish sample is public available for future updates including forensic and population genetic studies. New initiatives to categorise Y-SNP variation in other populations according to the reference phylogeny of the Y chromosome are highly encouraged for forensic applications. Recommendations to realise such future population sample sets are discussed based on this study.