The formation of proto-austronesians: insights from a revised phylogeography of the paternal founder lineage.

OBJECTIVES: Previous studies suggested that the Y-chromosome haplogroups O2-N6-B451-AM01756 and O1a-M119 are two founder lineages of proto-Austronesians at about five thousand years ago. The objective of this study was to investigate the formation of proto-Austronesians from the perspective of the paternal gene pool. MATERIALS AND METHODS: In this study, we developed a highly evised phylogenetic tree with age estimates for haplogroup O2-N6 and early branches of O1a-M119 (M110, F1036, and F819). In addition, we also explored the geographical distribution of eight sub-branches of O2-N6 and O1a-M119, and spatial autocorrelation analysis was conducted for each sub-branch. RESULTS: The paternal lineage combination of proto-Austronesians is a small subset of a diverse gene pool of populations from the mainland of East Asia. The distribution map and results of the spatial autocorrelation analysis suggested that the eastern coastal region of northern China is likely the source of lineage O2-N6 while the coastal region of southeastern China is likely the diffusion center of early branches of O1a-M119. We developed an evolutionary diagram for Austronesians and their ancestors in the past 18,000 years. DISCUSSION: We proposed that the millet farming community in North China is the common ancestor group of the Austronesians and the Han people, while the diverse ancient people in the southeast coastal areas of East Asia form the common ancestor group of the Austronesians and the East Asian mainland population. The demographic history of multiple ancestral groups of the most recent common ancestor group itself in the more ancient period is helpful to understand the deep roots of the genetic components and cultural traditions of Austronesians.

Post-last glacial maximum expansion of Y-chromosome haplogroup C2a-L1373 in northern Asia and its implications for the origin of Native Americans.

OBJECTIVES: Subbranches of Y-chromosome haplogroup C2a-L1373 are founding paternal lineages in northern Asia and Native American populations. Our objective was to investigate C2a-L1373 differentiation in northern Asia and its implications for Native American origins. MATERIALS AND METHODS: Sequences of rare subbranches (n = 43) and ancient individuals (n = 37) of C2a-L1373 (including P39 and MPB373), were used to construct phylogenetic trees with age estimation by BEAST software. RESULTS: C2a-L1373 expanded rapidly approximately 17.7,000-14.3,000 years ago (kya) after the last glacial maximum (LGM), generating numerous sublineages which became founding paternal lineages of modern northern Asian and Native American populations (C2a-P39 and C2a-MPB373). The divergence pattern supports possible initiation of differentiation in low latitude regions of northern Asia and northward diffusion after the LGM. There is a substantial gap between the divergence times of C2a-MPB373 (approximately 22.4 or 17.7 kya) and C2a-P39 (approximately 14.3 kya), indicating two possible migration waves. DISCUSSION: We discussed the decreasing time interval of "Beringian standstill" (2.5 ky or smaller) and its reduced significance. We also discussed the multiple possibilities for the peopling of the Americas: the "Long-term Beringian standstill model," the "Short-term Beringian standstill model," and the "Multiple waves of migration model." Our results support the argument from ancient DNA analyses that the direct ancestor group of Native Americans is an admixture of "Ancient Northern Siberians" and Paleolithic communities from the Amur region, which appeared during the post-LGM era, rather than ancient populations in greater Beringia, or an adjacent region, before the LGM.

Paternal origin of Tungusic-speaking populations: Insights from the updated phylogenetic tree of Y-chromosome haplogroup C2a-M86.

OBJECTIVES: Haplogroup C2a-M48 is the predominant paternal lineage of Tungusic-speaking populations, one of the largest population groups in Siberia. Up until now, the origins and dispersal of Tungusic-speaking populations have remained unclear. In this study, the demographic history of Tungusic-speaking populations was explored using the phylogenetic analysis of haplogroup C2a-M86, the major subbranch of C2a-M48. MATERIALS AND METHODS: In total, 18 newly generated Y chromosome sequences from C2a-M48 males and 20 previously available Y-chromosome sequences from this haplogroup were analyzed. A highly revised phylogenetic tree of haplogroup C2a-M86 with age estimates was reconstructed. Frequencies of this lineage in the literature were collected and a comprehensive analysis of this lineage in 13 022 individuals from 245 populations in Eurasia was performed. RESULTS: The distribution map of C2a-M48 indicated the most probable area of origin and diffusion route of this paternal lineage in North Eurasia. Most C2a-M86 samples from Tungusic-speaking populations belonged to the sublineage C2a-F5484, which emerged about 3300 years ago. We identified six unique sublineages corresponding to the Manchu, Evenks, Evens, Oroqen, and Daurpopulations; these sublineages diverged gradually over the past 1900 years. Notably, we observed a clear north-south dichotomous structure for sublineages derived from C2a-F5484, consistent with the internal north-south divergence of Tungusic languages and ethnic groups. CONCLUSIONS: We identified the important founding paternal haplogroup, C2a-F5484, for Tungusic-speaking populations as well as numerous unique subgroups of this haplogroup. We propose that the timeframe for the divergence of C2a-F5484 corresponds with the early differentiation of ancestral Tungusic-speaking populations.

Phylogenetic analysis of the Y-chromosome haplogroup C2b-F1067, a dominant paternal lineage in Eastern Eurasia.

Human Y-chromosome haplogroup C2b-F1067 is one of the dominant paternal lineages of populations in Eastern Eurasia. In order to explore the origin, diversification, and expansion of this haplogroup, we generated 206 new Y-chromosome sequences from C2b-F1067 males and coanalyzed 220 Y-chromosome sequences of this haplogroup. BEAST software was used to reconstruct a revised phylogenetic tree of haplogroup C2b-F1067 with age estimates. The revised phylogeny of C2b-F1067 included 155 sublineages, 1986 non-private variants, and >6000 private variants. The age estimation suggested that the initial splitting of C2b-F1067 happened at about 32.8 thousand years ago (kya) and the major sublineages of this haplgroup experienced continuous expansion in the most recent 10,000 years. We identified numerous sublineages that were nearly specific for Korean, Mongolian, Chinese, and other ethnic minorities in China. In particular, we evaluated the candidate-specific lineage for the Dayan Khan family and the Confucius family, the descendants of the ruling family of the Chinese Shang dynasty. These findings suggest that ancient populations with varied C2b-F1067 sublineages played an important role during the formation of most modern populations in Eastern Eurasia, and thus eventually became the founding paternal lineages of these populations.

The intragenic epistatic association of ADD3 with biliary atresia in Southern Han Chinese population.

Biliary atresia (BA) is a multifactorial pathogenic disease with possible genetic components. As a member of membrane skeletal proteins in the liver and bile ducts, a haplotype composed by five single nucleotide polymorphisms (SNPs) on adducin 3 (ADD3) has been identified as associated with BA. However, limited study was designed to further elaborate the mutual relationship amongst those replicated SNPs to disease. We selected three susceptibility SNPs in ADD3 and conducted a replication study using 510 BA cases and 1473 controls to evaluate the individual function of the SNPs and further stratified the potential roles with disease and its subclinical features. Two SNPs in ADD3 were replicated as associated with BA (1.60E-04 ≤ P≤1.70E-04, 1.33 ≤ odds ratio (OR) ≤ 1.58 for rs17095355, 2.10E-04 ≤ P≤5.30E-04, 1.26 ≤ OR ≤ 1.57 for rs2501577). Though we failed to replicate the individual association of rs10509906 to disease, the intragenic epistatic effect between rs10509906 and rs2501577 was suggested as exhibiting susceptibility to BA, further cross-validated by multifactor dimensionality reduction (MDR) (P=0.068, OR = 1.37), which may explain extra hidden heritability of ADD3 to BA. Furthermore, through subclinical stratification, we also observed the association of risk to disease mainly came from the female patients.

Estimation of stature by using the dimensions of the right hand and right foot in Han Chinese adults.

The Han Chinese people are the main ethnic group in China and the largest ethnic group in the world. The dimensions of the hands and feet have been successfully used for the estimation of stature. A total of 26,927 healthy adult subjects, comprising 13,221 men and 13,706 women, were recruited. The survey samples were chosen through random cluster sampling. The mean values were significantly higher in men than those in women for all measurements (P<0.001). All the measurements showed a statistically significant correlation with stature (P<0.01). The combination of the right hand length and the right foot length was the best predictor of stature because it had the lowest standard error of estimate. The use of multiple regression equations yielded better results than did the use of linear regression equations. The accuracy of stature prediction ranged from ±4.81 to ±6.39 cm. The present study was of great importance with regards to improving the physical anthropology database of ethnic groups in China.

Area-level socioeconomic disparities impact adult overweight and obesity risks of Han ethnicity in China.

OBJECTIVES: The profound socioeconomic processes occurring in developing countries have been accompanied by the notable increase of overweight and obese populations. This study for the first time investigates the impact of area-based socioeconomic status (SES) on adult overweight and obesity for both sexes of Han ethnicity in China. METHODS: We investigated 6,221 adult participants of Han ethnicity from 18 geographic areas in China, and measured stature and weight for each participant. The mean annual income per individual was chosen as the area-level SES index. We adopted logistic regression analysis to explore the relationship of area-level SES with overweight and obesity. RESULTS: The age-adjusted overweight and obesity prevalence was 32.46% for men and 29.27% for women respectively. Substantial area-level SES disparity in overweight and obesity risks for both sexes exist in China. The overweight and obesity prevalence rates increased with increasing SES levels in men rather than in women. CONCLUSION: Men living in high SES areas as well as women living at the lowest SES areas were most likely to be at the highest risk of overweight and obesity in China.

Ethnic inequalities and sex differences in body mass index among tibet minorities in China: implication for overweight and obesity risks.

OBJECTIVES: In the present study, we for the first time investigated overweight and obesity level among Tibet minorities (Deng, Lhoba, Monba) living in remote villages at the south slope of Qinghai-Tibetan Plateau, China. For each ethnicity, the total number of population is less than 10 thousands in China. METHODS: Anthropometric measurements were conducted on adult participants of three ethnicities in Tibet, China. Totally, the whole sample consists of 141 males and 163 females. Body mass index (BMI) was adopted to evaluate the overweight and obesity level. RESULTS: Within each ethnicity, there was no significant sex difference on BMI. The general prevalence of overweight and obesity level of Lhoba ethnicity (18.42%) is higher than that of Monba (17.65%) and Deng ethnicity (6.29%). For each sex, the distribution of BMI classification was found to be significantly associated with ethnicity identity. CONCLUSION: One possible reason for ethnic disparity among Tibet minorities in the present study is special dietary elements. Measures to prevent and cope with the problem of overweight and obesity among Tibet minorities are urgently required.

Brief communication: Body mass index, body adiposity index, and percent body fat in Asians.

Human obesity is a growing epidemic throughout the world. Body mass index (BMI) is commonly used as a good indicator of obesity. Body adiposity index (BAI = hip circumference (cm)/stature (m)(1.5) - 18), as a new surrogate measure, has been proposed recently as an alternative to BMI. This study, for the first time, compares BMI and BAI for predicting percent body fat (PBF; estimated from skinfolds) in a sample of 302 Buryat adults (148 men and 154 women) living in China. The BMI and BAI were strongly correlated with PBF in both men and women. The correlation coefficient between BMI and PBF was higher than that between BAI and PBF for both sexes. For the linear regression analysis, BMI better predicted PBF in both men and women; the variation around the regression lines for each sex was greater for BAI comparisons. For the receiver operating characteristic (ROC) analysis, the area under the ROC curve for BMI was higher than that for BAI for each sex, which suggests that the discriminatory capacity of the BMI is higher than the one of BAI. Taken together, we conclude that BMI is a more reliable indicator of PBF derived from skinfold thickness in adult Buryats.

Physical characteristics of Chinese Hakka.

Using standard and internationally validated methods, 86 anthropologic characteristics were determined in 650 male (305 from urban areas and 345 from rural areas) and 704 female (331 from urban areas, 373 from rural areas) Chinese Hakka adults living in Guangdong and Jiangxi. The data were used to calculate 24 anthropologic indices, which were analyzed statistically. The physical characteristics of Hakka subjects were analyzed and compared with reference ethnic data. There were four main findings of this study. First, a small proportion of Hakka adults had an eye fold on the upper eyelid, but a large proportion had a mongoloid fold. The eye slits were narrow in most adults, had a medium nasal root height and straight bridges, and most of the external angles were prominent. The nasal base was upturned in most men. The distributions of the three types of nasal base in women were similar. The proportions of subjects with middle and high alae nasi heights were high and similar. Males with a maximum nostril diameter were mostly classified as transverse and oblique, while many women were classified as transverse and had relatively wide alae nasi. The round lobe type was the most common. Upper lip skin height was mostly classified as medium. Lips were classified as thin. The hair was black, eyes were brown, and the skin was yellowish. Second, the head length was long in male Hakka. The minimum frontal breadth, face breadth, lip height, and interocular breadth were similar to those of North-Asian populations. Meanwhile, head breadth, morphological facial height, nose breadth, mouth breadth, and nose height were similar to those of South-Asian populations. Head length was long in female Hakka. The minimum frontal breadth, face breadth, lip height, and interocular breadth were similar to those of North-Asian populations. Head breadth, nose breadth, and mouth breadth were similar to those of South-Asian populations. Third, the stature of male and female Hakka in urban and rural areas was classified as medium. The proportions of male and female Hakka classified as mesocephaly (length-breadth index of the head), hypsicephalic type, metriocephalic type (breadth-height index of the head) mesorrhiny, long trunk, subbrachyskelic type, broad shoulder breadth, and narrow distance between iliac crests were higher than those of other types. Finally, principal component analyses showed that the physical characteristics of Hakka were between those of South-Asian and North-Asian ethnic populations, but were generally closer to those of North-Asian populations in China.

Morphological traits in peoples of Mongolian nationality of the Hulunbuir league, Inner Mongolia, China.

A sample of 947 Mongolians of Bargud, Elute and Buriat was investigated on 9 indexes (hair form, forehead hair-ledge point, eyefold of the upper eyelid, Mongoloid fold, ear lobe type, nasal profile, nostril type, front teeth type, and chin projection) in the Hulunbuir league, Inner Mongolia in September 1997. The results are as follows: 1. Most of the Mongolians in Hulunbuir league are characterised by straight hair, forehead hair-ledge point absence, eyefold eyelid, Mongoloid fold appearance, shovel-shaped front teeth, straight nose, wide nostril, free ear lobe, non-projecting chin. 2. The frequencies of the forehead hair-ledge point appearance, shovel-shaped front teeth appearance and projecting chin showed significant differences between the three groups. 3. The incidence of ear lobe type, nasal profile and front teeth type showed obvious sexual differences. 4. Correlations did not occur between most of the nine traits.

[Gene frequency of 12 characters in 5 nationalities in inner mongolia].

The gene frequency of 12 characters was reported in Ewenki, Oroqen, Daur, Mongol and Han nationalities in Inner Mongolia, and compared among these nationalities. The result indicated that the difference of Mongoloid fold among nationalities was significant, followed by the Folding tongue, while the difference of Handedness and Nasal profile was relatively insignificant.