Population genomics of East Asian ethnic groups

Genetic diversity among the present Japanese population: evidence from genotyping of human cell lines established in Japan

Japan is often assumed to have a highly homogeneous ethnic population, because it is an island country. This is evident in human cell lines collected from cell banks; however, these genotypes have not been thoroughly characterized. To examine the population genotypes of human cell lines established in Japan, we conducted SNP genotyping on 57 noncancerous cell lines and 43 lung cancer cell lines. Analysis of biogeographic ancestry revealed that 58 cell lines had non-admixed Japanese genotypes, 21 cell lines had an admixture of Japanese and East Asian genotypes, and the remaining 21 cell lines had East Asian genotypes. The proportion of non-admixed Japanese genotypes was similar between lung cancer and noncancerous cell lines, suggesting that patients in Japan may not exclusively have Japanese genotypes. This could influence the incidence of inherited diseases and should be taken into account in personalized medicine tailored to genetic background. The genetic makeup of the present-day Japanese population cannot be fully explained by the ancestral Jomon and Yayoi lineages. Instead, it is necessary to consider a certain level of genetic admixture between Japanese and neighboring Asian populations. Our study revealed genetic variation among human cell lines derived from Japanese individuals, reflecting the diversity present within the Japanese population.

Introducing Saddle-Shaped Radix Graft, with a Second Look into the Classic

BACKGROUND

An enduringly stable tip graft is the key to achieve successful rhinoplasty cases. However, the intrinsic nature of rib graft warping renders major unpredictability for the long-term outcome. The objective of this study was to detail and validate the use of a radix graft design that is characterized by the dual curved surfaces and beveled margin, which consequently renders a shape similar to a saddle.

METHODS

Twenty-three female patients, ranging in age from 22 to 31 years, completed the study. In all cases, the saddle-shaped radix graft was applied as the essential element for enhancing radix region profile. The complications that arose were collected retrospectively. Three-dimensional stereophotogrammetric evaluations of patients were performed. Anthropometric points were analyzed in a blinded fashion. Outcome variables were tip projection, nasal length, radix height, and the radius of curvature.

RESULTS

Postoperative analysis suggested significant improvement on the aesthetics of the radix region over time, evidenced by the significant increase of radix height (4.33 ± 1.21 mm versus 7.08 ± 1.00 mm), and the reduction of radius of curvature at nasofrontal break over the long term (22.63 ± 2.24 mm versus 13.94 ± 0.98 mm). Other postoperative evaluations, including radix height, tip projection, and nasal length, had significant improvement.

CONCLUSIONS

The saddle-shaped radix graft effectively augments the radix area and creates an aesthetically pleasant nasofrontal break without causing the elevated radix deformity. It has the merits of anatomical compliance and flexibility when it comes to concomitantly improving the glabella-radix profile for those East Asians with extremely low radix.

The relay graft, a tailored supplement between the nasal hump and established tip in East Asian rhinoplasty

BACKGROUND

In East Asian individuals, the nasal bone already has sufficient height for an ideal dorsal profile, but the tip requires enhancement for a desired projection. Consequently, the gap between the intrinsic bony structure and the established nasal tip requires appropriate management. The options are either to reduce the keystone region to create a smooth bed for a conventional dorsal onlay graft or to preserve the original osseocartilaginous structures and then customize a supplementary graft. The aim of this study was to detail and validate the utilization of a relay graft, a transition graft that fills the structural gap between the upper dorsum and established tip graft. The proper application of this graft could prevent osteotomy and preserve the intrinsic dorsum.

METHODS

Relay grafts were applied during rib-based rhinoplasty in East Asian patients. Three-dimensional stereophotogrammetric evaluations of the patients were performed. Anthropometric points were analyzed in a blinded fashion. Outcome variables were tip projection improvement, radix elevation, and the angulation of kyphion and pronasale.

RESULTS

Fifteen female patients, ranging in age from 21 to 40 years (average 24.5 years), were included. In all cases, the relay graft was applied as one essential element for filling the structural gap. No crooked dorsal profile or visible graft was noted in all cases. Fifteen patients completed the pre- and postoperative stereophotogrammetric study. Postoperative analysis showed great improvement of tip position as well as a slight elevation of the radix, evidenced by the consistent change of kyphion/pronasale angulation and sellion elevation.

CONCLUSIONS

The relay graft effectively mitigates the necessity of a disruptive dorsal reduction. It is entirely possible for East Asians to achieve a smooth dorsal profile when only the lower half of the dorsum is transitioned to the proposed tip position.

LEVEL OF EVIDENCE

Level IV, case series.

Sleep and allergic diseases among young Chinese adults from the Singapore/Malaysia Cross-Sectional Genetic Epidemiology Study (SMCGES) cohort

BACKGROUND AND OBJECTIVE

Sleep disruption has been shown to affect immune function and thus influence allergic disease manifestation. The specific effects of sleep on allergic diseases, however, are less well-established; hence, in a unique population of young Chinese adults, we investigated the association between sleep and allergic disease.

METHODS

Young Chinese adults recruited from Singapore in the Singapore/Malaysia Cross-Sectional Genetic Epidemiology Study (SMCGES) were analyzed. We used the International Study of Asthma and Allergies in Childhood (ISAAC) protocol and a skin prick test to determine atopic dermatitis (AD), allergic rhinitis (AR), and asthma status. Information regarding total sleep time (TST) and sleep quality (SQ) was also obtained.

RESULTS

Of 1558 participants with a mean age of 25.0 years (SD = 7.6), 61.4% were female, and the mean total sleep time (TST) was 6.8 h (SD = 1.1). The proportions of AD, AR, and asthma were 24.5% (393/1542), 36.4% (987/1551), and 14.7% (227/1547), respectively. 59.8% (235/393) of AD cases suffered from AD-related sleep disturbances, 37.1% (209/564) of AR cases suffered from AR-related sleep disturbances, and 25.1% (57/227) of asthma cases suffered from asthma-related sleep disturbances. Only asthma cases showed a significantly lower mean TST than those without asthma (p = 0.015). Longer TST was significantly associated with lower odds of AR (OR = 0.905, 95% CI = 0.820-0.999) and asthma (OR = 0.852, 95% CI = 0.746-0.972). Linear regression analyses showed that lower TST was significantly associated with asthma (β =  - 0.18, SE = 0.076, p-value = 0.017), and AR when adjusted for AR-related sleep disturbances (β =  - 0.157, SE = 0.065, p-value = 0.016). Only sleep disturbances due to AR were significantly associated with a poorer SQ (OR = 1.962, 95% CI = 1.245-3.089).

CONCLUSIONS

We found that sleep quality, but not sleep duration was significantly poorer among AD cases, although the exact direction of influence could not be determined. In consideration of the literature coupled with our findings, we posit that TST influences allergic rhinitis rather than vice versa. Finally, the association between TST and asthma is likely mediated by asthma-related sleep disturbances, since mean TST was significantly lower among those with nighttime asthma symptoms. Future studies could consider using objective sleep measurements coupled with differential expression analysis to investigate the pathophysiology of sleep and allergic diseases.

Targeted sequencing of high-density SNPs provides an enhanced tool for forensic applications and genetic landscape exploration in Chinese Korean ethnic group

BACKGROUND

In this study, we present a NGS-based panel designed for sequencing 1993 SNP loci for forensic DNA investigation. This panel addresses unique challenges encountered in forensic practice and allows for a comprehensive population genetic study of the Chinese Korean ethnic group. To achieve this, we combine our results with datasets from the 1000 Genomes Project and the Human Genome Diversity Panel.

RESULTS

We demonstrate that this panel is a reliable tool for individual identification and parentage testing, even when dealing with degraded DNA samples featuring exceedingly low SNP detection rates. The performance of this panel for complex kinship determinations, such as half-sibling and grandparent-grandchild scenarios, is also validated by various kinship simulations. Population genetic studies indicate that this panel can uncover population substructures on both global and regional scales. Notably, the Han population can be distinguished from the ethnic minorities in the northern and southern regions of East Asia, suggesting its potential for regional ancestry inference. Furthermore, we highlight that the Chinese Korean ethnic group, along with various Han populations from different regional areas and certain northern ethnic minorities (Daur, Tujia, Japanese, Mongolian, Xibo), exhibit a higher degree of genetic affinities when examined from a genomic perspective.

CONCLUSION

This study provides convincing evidence that the NGS-based panel can serve as a reliable tool for various forensic applications. Moreover, it has helped to enhance our knowledge about the genetic landscape of the Chinese Korean ethnic group.

Frequency of actionable secondary findings in 7472 Korean genomes derived from the National Project of Bio Big Data pilot study

Exome and genome sequencing (ES/GS) in genetic medicine and research leads to discovering genomic secondary findings (SFs) unrelated to the purpose of the primary test. There is a lack of agreement to return the SF results for individuals undergoing the test. The aim of this study is to investigate the frequency of actionable secondary findings using GS data obtained from the rare disease study and the Korean Genome and Epidemiology Study (KoGES) in the National Project of Bio Big Data pilot study. Pathogenic (P) or likely pathogenic (LP) variants of 78 SF genes recommended by the American College of Medical Genetics and Genomics (ACMG) were screened in the rare disease study and KoGES. The pathogenicity of SF gene variants was determined according to the ACMG interpretation. The overall SF rate was 3.75% for 280 individuals with 298 P/LP variants of 41 ACMG SF genes which were identified among 7472 study participants. The frequencies of genes associated with cardiovascular, cancer, and miscellaneous phenotypes were 2.17%, 1.22%, and 0.58%, respectively. The most frequent SF gene was TTN followed by BRCA2. The frequency of actionable SFs among participants with rare disease and general population participants in the Korean population presented here will assist in reporting results of medically actionable SFs in genomic medicine.

Genome-wide DNA methylation landscape of four Chinese populations and epigenetic variation linked to Tibetan high-altitude adaptation

DNA methylation (DNAm) is one of the major epigenetic mechanisms in humans and is important in diverse cellular processes. The variation of DNAm in the human population is related to both genetic and environmental factors. However, the DNAm profiles have not been investigated in the Chinese population of diverse ethnicities. Here, we performed double-strand bisulfite sequencing (DSBS) for 32 Chinese individuals representing four major ethnic groups including Han Chinese, Tibetan, Zhuang, and Mongolian. We identified a total of 604,649 SNPs and quantified DNAm at more than 14 million CpGs in the population. We found global DNAm-based epigenetic structure is different from the genetic structure of the population, and ethnic difference only partially explains the variation of DNAm. Surprisingly, non-ethnic-specific DNAm variations showed stronger correlation with the global genetic divergence than these ethnic-specific DNAm. Differentially methylated regions (DMRs) among these ethnic groups were found around genes in diverse biological processes. Especially, these DMR-genes between Tibetan and non-Tibetans were enriched around high-altitude genes including EPAS1 and EGLN1, suggesting DNAm alteration plays an important role in high-altitude adaptation. Our results provide the first batch of epigenetic maps for Chinese populations and the first evidence of the association of epigenetic changes with Tibetans' high-altitude adaptation.

Systematic selection of ancestry informative SNPs for differentiating Han, Japanese, Dai, and Kinh populations

Biogeographical origin inferences of different populations can provide valuable clues in the forensic investigation by narrowing down the detection scope. However, much research mainly focuses on forensic ancestral origin analyses of major continental populations, which may provide limited information in forensic practice. To improve the ancestral resolution of East Asian populations, we systematically selected ancestry informative single-nucleotide polymorphisms (AISNPs) for differentiating Han, Dai, Japanese, and Kinh populations. In addition, we evaluated the performance of the selected AISNPs to differentiate these populations via multiple methods. Totally 116 AISNPs were selected from the genome-wide data to infer the population origins of these four populations. Results of principle component analysis and population genetic structure of these populations indicated that the selected 116 AISNPs could achieve ancestral resolution of most individuals. Furthermore, the machine learning model built by 116 AISNPs unveiled that most individuals from these four populations could be assigned to correct population origins. To sum up, the selected 116 SNPs could be available for ancestral origin predictions of Han, Dai, Japanese, and Kinh populations, which could provide valuable information for forensic research and genome-wide association study in East Asian populations to some extent.

Differential regulation of the interferon response in systemic lupus erythematosus distinguishes patients of Asian ancestry

OBJECTIVES

Type I interferon (IFN) plays a role in the pathogenesis of systemic lupus erythematosus (SLE), but insufficient attention has been directed to the differences in IFN responses between ancestral populations. Here, we explored the expression of the interferon gene signatures (IGSs) in SLE patients of European ancestry (EA) and Asian ancestry (AsA).

METHODS

We used gene set variation analysis with multiple IGS encompassing the response to both type 1 and type 2 IFN in isolated CD14+ monocytes, CD19+B cells, CD4+T cells and Natural Killer (NK) cells from patients with SLE stratified by self-identified ancestry. The expression of genes upstream of the IGS and influenced by lupus-associated risk alleles was also examined. Lastly, we employed machine learning (ML) models to assess the most important features classifying patients by disease activity.

RESULTS

AsA patients with SLE exhibited greater enrichment in the IFN core and IFNA2 IGS compared with EA patients in all cell types examined and, in the presence and absence of autoantibodies. Overall, AsA patients with SLE demonstrated higher expression of genes upstream of the IGS than EA counterparts. ML with feature importance analysis indicated that IGS expression in NK cells, anti-dsDNA, complement levels and AsA status contributed to disease activity.

CONCLUSIONS

AsA patients with SLE exhibited higher IGS than EA patients in all cell types regardless of autoantibody status, with enhanced expression of genetically associated genes upstream of the IGS potentially contributing. AsA, along with the IGS in NK cells, anti-dsDNA and complement, independently influenced SLE disease activity.

Association between genetic predisposition and disease burden of stroke in China: a genetic epidemiological study

Background

Stroke ranks second worldwide and first in China as a leading cause of death and disability. It has a polygenic architecture and is influenced by environmental and lifestyle factors. However, it remains unknown as to whether and how much the genetic predisposition of stroke is associated with disease burden.

Methods

Allele frequency from the whole genome sequencing data in the Chinese Millionome Database of 141,418 individuals and trait-specific polygenic risk score models were applied to estimate the provincial genetic predisposition to stroke, stroke-related risk factors and stroke-related drug response. Disease burden including mortality, disability-adjusted life years (DALYs), years of life lost(YLLs), years lived with disability (YLDs) and prevalence in China was collected from the Global Burden Disease study. The association between stroke genetic predisposition and the epidemiological burden was assessed and then quantified in both regression-based models and machine learning-based models at a provincial resolution.

Findings

Among the 30 administrative divisions in China, the genetic predisposition of stroke was characterized by a north-higher-than-south gradient (p < 0.0001). Genetic predisposition to stroke, blood pressure, body mass index, and alcohol use were strongly intercorrelated (rho >0.6; p < 0.05 after Bonferroni correction for each comparison). Genetic risk imposed an independent effect of approximately 1-6% on mortality, DALYs and YLLs.

Interpretation

The distribution pattern of stroke genetic predisposition is different at a macroscopic level, and it subtly but significantly impacts the epidemiological burden. Further research is warranted to identify the detailed aetiology and potential translation into public health measures.

Funding

Beijing Municipal Science and Technology Commission (Z191100006619106), CAMS Innovation Fund for Medical Sciences (CAMS-I2M, 2023-I2M-1-001), the National High Level Hospital Clinical Research Funding (2022-GSP-GG-17), National Natural Science Foundation of China (32000398, 32171441 to X.J.), Natural Science Foundation of Guangdong Province, China (2017A030306026 to X.J.), and National Key R&D Program of China (2022YFC2502402).

Genome-wide allele and haplotype-sharing patterns suggested one unique Hmong-Mein-related lineage and biological adaptation history in Southwest China

BACKGROUND

Fine-scale genetic structure of ethnolinguistically diverse Chinese populations can fill the gap in the missing diversity and evolutionary landscape of East Asians, particularly for anthropologically informed Chinese minorities. Hmong-Mien (HM) people were one of the most significant indigenous populations in South China and Southeast Asia, which were suggested to be the descendants of the ancient Yangtze rice farmers based on linguistic and archeological evidence. However, their deep population history and biological adaptative features remained to be fully characterized.

OBJECTIVES

To explore the evolutionary and adaptive characteristics of the Miao people, we genotyped genome-wide SNP data in Guizhou HM-speaking populations and merged it with modern and ancient reference populations via a comprehensive population genetic analysis and evolutionary admixture modeling.

RESULTS

The overall genetic admixture landscape of Guizhou Miao showed genetic differentiation between them and other linguistically diverse Guizhou populations. Admixture models further confirmed that Miao people derived their primary ancestry from geographically close Guangxi Gaohuahua people. The estimated identity by descent and effective population size confirmed a plausible population bottleneck, contributing to their unique genetic diversity and population structure patterns. We finally identified several natural selection candidate genes associated with several biological pathways.

CONCLUSIONS

Guizhou Miao possessed a specific genetic structure and harbored a close genetic relationship with geographically close southern Chinese indigenous populations and Guangxi historical people. Miao people derived their major ancestry from geographically close Guangxi Gaohuahua people and experienced a plausible population bottleneck which contributed to the unique pattern of their genetic diversity and structure. Future ancient DNA from Shijiahe and Qujialing will provide new insights into the origin of the Miao people.

Pharmacogenomic variabilities in geo-ancestral subpopulations and their clinical implications: Results of collaborations with Hmong in the United States

Underrepresentation of subpopulations within geo-ancestral groups engaged in research can exacerbate health disparities and impair progress toward personalized medicine. This is particularly important when implementing pharmacogenomics which uses genomic-based sources of variability to guide medication selection and dosing. This mini-review focuses on pharmacogenomic findings with Hmong in the United States and their potential clinical implications. By actively engaging Hmong community in pharmacogenomic-based research, several clinically relevant differences in allele frequencies were observed within key pharmacogenes such as CYP2C9 and CYP2C19 in Hmong compared to those in either East Asians or Europeans. Additionally, using state-of-the-art genome sequencing approaches, Hmong appear to possess novel genetic variants within CYP2D6, a critical pharmacogene affecting pharmacokinetics of a broad range of medications. The allele frequency differences and novel alleles in Hmong have translational impact and real-world clinical consequences. For example, Hmong patients exhibited a lower warfarin stable dose requirement compared to East Asian patients. This was predicted based on Hmong's unique genetic and non-genetic factors and confirmed using real-world data from clinical practice settings. By presenting evidence of the genetic uniqueness and its translational impact within subpopulations, such as the Hmong, we hope to inspire greater inclusion of other geo-ancestrally underrepresented subpopulations in pharmacogenomic-based research.

Core promoter in TNBC is highly mutated with rich ethnic signature

The core promoter plays an essential role in regulating transcription initiation by controlling the interaction between transcriptional factors and sequence motifs in the core promoter. Although mutation in core promoter sequences is expected to cause abnormal gene expression leading to pathogenic consequences, limited supporting evidence showed the involvement of core promoter mutation in diseases. Our previous study showed that the core promoter is highly polymorphic in worldwide human ethnic populations in reflecting human history and adaptation. Our recent characterization of the core promoter in triple-negative breast cancer (TNBC), a subtype of breast cancer, in a Chinese TNBC cohort revealed the wide presence of core promoter mutation in TNBC. In the current study, we analyzed the core promoter in a Thai TNBC cohort. We also observed rich core promoter mutation in the Thai TNBC patients. We compared the core promoter mutations between Chinese and Thai TNBC cohorts. We observed substantial differences of core promoter mutation in TNBC between the two cohorts, as reflected by the mutation spectrum, mutation-effected gene and functional category, and altered gene expression. Our study confirmed that the core promoter in TNBC is highly mutable, and is highly ethnic-specific.

Genetic evidence of tri-genealogy hypothesis on the origin of ethnic minorities in Yunnan

BACKGROUND

Yunnan is located in Southwest China and consists of great cultural, linguistic, and genetic diversity. However, the genomic diversity of ethnic minorities in Yunnan is largely under-investigated. To gain insights into population history and local adaptation of Yunnan minorities, we analyzed 242 whole-exome sequencing data with high coverage (~ 100-150 ×) of Yunnan minorities representing Achang, Jingpo, Dai, and Deang, who were linguistically assumed to be derived from three ancient lineages (the tri-genealogy hypothesis), i.e., Di-Qiang, Bai-Yue, and Bai-Pu.

RESULTS

Yunnan minorities show considerable genetic differences. Di-Qiang populations likely migrated from the Tibetan area about 6700 years ago. Genetic divergence between Bai-Yue and Di-Qiang was estimated to be 7000 years, and that between Bai-Yue and Bai-Pu was estimated to be 5500 years. Bai-Pu is relatively isolated, but gene flow from surrounding Di-Qiang and Bai-Yue populations was also found. Furthermore, we identified genetic variants that are differentiated within Yunnan minorities possibly due to the living circumstances and habits. Notably, we found that adaptive variants related to malaria and glucose metabolism suggest the adaptation to thalassemia and G6PD deficiency resulting from malaria resistance in the Dai population.

CONCLUSIONS

We provided genetic evidence of the tri-genealogy hypothesis as well as new insights into the genetic history and local adaptation of the Yunnan minorities.

Building the Nation: The Success and Crisis of Korean Civil Religion

Civil religion refers to a country’s beliefs, symbols, and rituals that bolster national unity and strengthen its citizens’ sense of identity and belonging. However, the literature on civil religion is divided between those who attribute it to bottom-up cultural spontaneity and those who see it as an ideological top-down construction. Moreover, there has been a relative lack of scholarly attention to Korean civil religion. This paper addresses both issues by arguing that a strong civil religion indeed exists in the country and that it has been an important part of the “nation-building” process since the founding of the Republic of Korea in 1948. The paper highlights how a succession of authoritarian regimes (1948–1987) successfully mobilized a strong civil religion for political purposes. The resulting civil religion targeted economic growth as the national goal to overcome all social ills, focused on the country’s ethnic and cultural homogeneity to boost national confidence and pride, exalted its traditional religions, especially Confucianism, as repositories of Korean traditional culture, and rendered sacred meanings to national symbols such as the flag and national anthem. Even after democratization, Korean civil religion remains largely ideological, as the Korean government is heavily involved in framing, planning, sponsoring, and promoting the country’s civil religion. Nevertheless, the paper concludes by observing that this civil religion is entering a period of crisis due to political fragmentation among Korean elites and deeply rooted cultural and societal change.