Subdividing Y-chromosome haplogroup R1a1 reveals Norse Viking dispersal lineages in Britain

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.

Inference of population structure and admixture proportion from Y chromosomal data of Chinese population

In the past two decades, Y chromosome data has been generated for human population genetic studies. These Y chromosome datasets were produced with various testing methods and markers, thus difficult to combine them for a comprehensive analysis. In this study, we combine four human Y chromosomal datasets of Han, Tibetan, Hui, and Li ethnic groups. The dataset contains 27 microsatellites and 137 single nucleotide polymorphisms these populations share in common. We assembled a single dataset containing 2439 individuals from 25 nationwide populations in China. A systematic analysis of genetic distance and clustering was performed. To determine the gene flow of the studied population with worldwide populations, we modeled the ancestry informative markers. The reference panel was regarded as a mixture of South Asian (SAS), East Asian (EAS), European (EUR), African (AFR), and American (AMR) populations from 1000 Genomes data of Y chromosome using nonlinear data-fitting. We then calculated the admixture proportion of these four studied populations with 26 worldwide populations. The results showed that the Han and Hui have great genetic affinity, and Hui is the most admixed ethnic group, with 61.53% EAS, 34.65% SAS, 1.91% AFR, 1.56% AMR, and 0.04% EUR ancestry component (the AMR is highly admixed and thus should be ignored). All the other three ethnic groups contained more than 97% EAS ancestry component. The Li is the least admixed population in this study. The combined dataset in this study is the largest of this kind reported to date and proposes reference population data for use in future paternal genetic studies and forensic genealogical identification.

Paternal genetic structure of the Qiang ethnic group in China revealed by high-resolution Y-chromosome STRs and SNPs

The Qiang population mainly lived in Beichuan Qiang Autonomous County of Sichuan Province. It is one of the nomads in China, distributed along the Minjiang River. The Qiang population was assumed to have great affinity with the Han, the largest ethnic group in China, when it refers to the genetic origin. Whereas, it is deeply understudied, especially from the Y chromosome. Here in this study, we used validated high-resolution Y-chromosome single nucleotide polymorphisms (Y-SNPs) and short tandem repeats (Y-STRs) panels to study the Qiang ethnic group to unravel their paternal genetic, forensic and phylogenetic characteristics. A total of 422 male samples of the Qiang ethnic group were genotyped by 233 Y-SNPs and 29 Y-STRs. Haplogroup O-M175 (N = 312) was the most predominant haplogroup in the Qiang ethnic group, followed by D-M174 (N = 32) and C-M130 (N = 32), N-M231 (N = 27), and Q-M242 (N = 15). After further subdivision, O2a-M324 (N = 213) accounted for the majority of haplogroup O. Haplogroup C2b-Z1338 (N = 29), D1a-CTS11577 (N = 30). O2a2b1a1a1-F42 (N = 48), O2a1b1a1a1a-F11 (N = 35), and O2a2b1a1-M117 (N = 21) represented other large terminal haplogroups. The results unveiled that Qiang ethnic group was a population with a high percentage of haplogroup O2a2b1a1a1-F42 (48/422) and O2a1b1a1a1a-F11 (35/422), and O2a2b1a1-M117 (21/422), which has never been reported. Its haplogroup distribution pattern was different from any of the Han populations, implying that the Qiang ethnic group had its unique genetic pattern. Mismatch analysis indicated that the biggest mismatch number in haplogroup O2a2b1a1a1-F42 was 21, while that of haplogroup O2a1b1a1a1a-F11 was 20. The haplotype diversity of the Qiang ethnic group equaled 0.999788, with 392 haplotypes observed, of which 367 haplotypes were unique. The haplogroup diversity of the Qiang ethnic group reached 0.9767, and 53 terminal haplogroups were observed (The haplogroup diversity of the Qiang ethnic group was the highest among Qiang and all Han subgroups, indicating the larger genetic diversity of the Qiang ethnic group.). Haplogroup O2a2b1a1a1-F42 was the most predominant haplogroup, including 11.37 % of the Qiang individuals. Median-joining trees showed gene flow between the Qiang and Han individuals. Our results indicated that 1) the highest genetic diversity was observed in the Qiang ethnic group compared to any of the former studied Chinese population, suggesting that the Qiang might be an older paternal branch; 2) the haplogroup D-M174 individuals of Qiang, Tibetans and Japanese distributed in three different subclades, which was unable to identify through low-resolution Y-SNP panel; and 3) the Qiang had lower proportion of haplogroup D compared to Yi and Tibetan ethnic groups, showing that the Qiang had less genetic communication with them than with Han Chinese.

Fitness and Power: The Contribution of Genetics to the History of Differential Reproduction

Textual evidence from pre-modern societies supports the prediction that status differences among men translate to variance in reproductive success. In recent years, analysis of genetic data has opened up new ways of studying this relationship. By investigating cases that range over several millennia, these analyses repeatedly document the replacement of local men by newcomers and reveal instances of exceptional reproductive success of specific male lineages. These findings suggest that violent population transfers and conquests could generate considerable reproductive advantages for male dominants. At the same time, this does not always seem to have been the case. Moreover, it is difficult to link such outcomes to particular historical characters or events, or to identify status-biased reproductive inequalities within dominant groups. The proximate factors that mediated implied imbalances in reproductive success often remain unclear. A better understanding of the complex interplay between social power and genetic fitness will only arise from sustained transdisciplinary engagement.