Polygenic adaptation leads to a higher reproductive fitness of native Tibetans at high altitude.

The adaptation of Tibetans to high-altitude environments has been studied extensively. However, the direct assessment of evolutionary adaptation, i.e.

High Arterial Oxygen Saturation in the Acclimatized Lowlanders Living at High Altitude.

Unlabelled: Blood oxygen saturation (SpO) is a key indicator of oxygen availability in the body. It is known that a low SpO at high altitude is associated with morbidity and mortality risks due to physiological hypoxemia. Previously, it was proposed that the lowlander immigrants living at high altitude should have a lower SpO level compared to the highlander natives, but this proposal has not been rigorously tested due to the lack of data from the lowlander immigrants living at high altitude.

Large-scale genome sequencing redefines the genetic footprints of high-altitude adaptation in Tibetans.

Background: Tibetans are genetically adapted to high-altitude environments. Though many studies have been conducted, the genetic basis of the adaptation remains elusive due to the poor reproducibility for detecting selective signatures in the Tibetan genomes.

Results: Here, we present whole-genome sequencing (WGS) data of 1001 indigenous Tibetans, covering the major populated areas of the Qinghai-Tibetan Plateau in China.

Seasonality and Sex-Biased Fluctuation of Birth Weight in Tibetan Populations.

Unlabelled: Birth weight (BW) is a key determinant of infant mortality. Previous studies have reported seasonal fluctuation of BW. However, the responsible environmental factors remain disputable.

Associations of long-term exposure to ambient air pollution and physical activity with insomnia in Chinese adults.

Background: Air pollution is a potential environmental risk for sleep disturbance. However, the evidence is very limited in China. On the other hand, physical activity (PA) is a preventive behavior that can improve insomnia, but whether PA mitigates the negative impact of air pollution on insomnia is unknown.

Chromatin accessibility landscape and regulatory network of high-altitude hypoxia adaptation.

High-altitude adaptation of Tibetans represents a remarkable case of natural selection during recent human evolution. Previous genome-wide scans found many non-coding variants under selection, suggesting a pressing need to understand the functional role of non-coding regulatory elements (REs). Here, we generate time courses of paired ATAC-seq and RNA-seq data on cultured HUVECs under hypoxic and normoxic conditions.

The Transcriptomic Landscape of Yaks Reveals Molecular Pathways for High Altitude Adaptation.

Yak is one of the largest native mammalian species at the Himalayas, the highest plateau area in the world with an average elevation of >4,000 m above the sea level. Yak is well adapted to high altitude environment with a set of physiological features for a more efficient blood flow for oxygen delivery under hypobaric hypoxia. Yet, the genetic mechanism underlying its adaptation remains elusive.

contributes to high-altitude adaptation in Tibetans by regulating nitric oxide production.

The genetic adaptation of Tibetans to high altitude hypoxia likely involves a group of genes in the hypoxic pathway, as suggested by earlier studies. To test the adaptive role of the previously reported candidate gene (histone acetyltransferase p300), we conducted resequencing of a 108.9 kb gene region of in 80 unrelated Tibetans.

plays a role in the high-altitude adaptation of Tibetans.

Tibetans are well adapted to high-altitude hypoxia. Previous genome-wide scans have reported many candidate genes for this adaptation, but only a few have been studied. Here we report on a hypoxia gene ( , GTP-cyclohydrolase I), involved in maintaining nitric oxide synthetase (NOS) function and normal blood pressure, that harbors many potentially adaptive variants in Tibetans.

Sherpas share genetic variations with Tibetans for high-altitude adaptation.

Background: Sherpas, a highlander population living in Khumbu region of Nepal, are well known for their superior climbing ability in Himalayas. However, the genetic basis of their adaptation to high-altitude environments remains elusive.

Methods: We collected DNA samples of 582 Sherpas from Nepal and Tibetan Autonomous Region of China, and we measured their hemoglobin levels and degrees of blood oxygen saturation.

Down-Regulation of EPAS1 Transcription and Genetic Adaptation of Tibetans to High-Altitude Hypoxia.

Tibetans are well adapted to the hypoxic environments at high altitude, yet the molecular mechanism of this adaptation remains elusive. We reported comprehensive genetic and functional analyses of EPAS1, a gene encoding hypoxia inducible factor 2α (HIF-2α) with the strongest signal of selection in previous genome-wide scans of Tibetans. We showed that the Tibetan-enriched EPAS1 variants down-regulate expression in human umbilical endothelial cells and placentas.

Validity and reliability of the Tibetan version of s-EMBU for measuring parenting styles.

Parenting style experienced during childhood has profound effects on children's futures. Scales developed in other countries have never been validated in the Tibetan context. The present study aimed to examine the construct validity and reliability of a Tibetan translation of the 23-item short form of the Egna Minnen Beträffande Uppfostran [One's Memories of Upbringing] (s-EMBU) and to test the correlation between the parenting styles of fathers and mothers.

HMOX2 Functions as a Modifier Gene for High-Altitude Adaptation in Tibetans.

Tibetans are well adapted to high-altitude environments. Among the adaptive traits in Tibetans, the relatively low hemoglobin level is considered a blunted erythropoietic response to hypoxic challenge. Previously, EPAS1 and EGLN1, the major upstream regulators in the hypoxic pathway, were reportedly involved in the hemoglobin regulation in Tibetans.

Genetic evidence of a recent Tibetan ancestry to Sherpas in the Himalayan region.

Sherpas living around the Himalayas are renowned as high-altitude mountain climbers but when and where the Sherpa people originated from remains contentious. In this study, we collected DNA samples from 582 Sherpas living in Nepal and Tibet Autonomous Region of China to study the genetic diversity of both their maternal (mitochondrial DNA) and paternal (Y chromosome) lineages. Analysis showed that Sherpas share most of their paternal and maternal lineages with indigenous Tibetans, representing a recently derived sub-lineage.

HIF2A Variants Were Associated with Different Levels of High-Altitude Hypoxia among Native Tibetans.

Hypoxia inducible factors, including HIF1A and HIF2A, play central roles in response to high-altitude hypoxia and genetic variants of HIF1A or HIF2A were associated with high-altitude sickness or adaptation. However, it remains to determine whether they are associated with tolerance to different levels of high-altitude selection pressure among native Tibetans. We recruited 189 Tibetan subjects living at 2,700 meters (Low level of high altitude, LHA), 197 at 3,200 meters (Middle level of high altitude of high altitude, MHA), 249 at 3,700 meters (High level of high altitude, HHA) and 269 at 4,700 meters (Very high level of high altitude, VHA) and performed association analysis of twelve tSNPs (tagging SNPs) in HIF1A and HIF2A with high-altitude.

A genetic adaptive pattern-low hemoglobin concentration in the Himalayan highlanders.

Mean hemoglobin (Hb) concentration of about 3 500 subjects derived from 17 studies of Himalayan highlanders (Tibetans, Sherpas, and Ladakhis) was compared with lowlanders (Chinese Han, Indian Tamils) lived in the Himalayas, and European climbers during Everest expeditions as well as Andean natives. The results found that Hb concentration in Himalayan highlanders was systemically lower than those reported for Andean natives and lowland immigrants. These comparative data demonstrated that a healthy native population may successfully reside at high altitude without a significant elevation in Hb, and the lower Hb levels of Himalayan highlanders than those of migrated lowlanders and Andean natives are an example of favourable adaptation over the generations.

Physiological responses and evaluation of effects of BMI, smoking and drinking in high altitude acclimatization: a cohort study in Chinese Han young males.

High altitude acclimatization is a series of physiological responses taking places when subjects go to altitude. Many factors could influence these processes, such as altitude, ascending speed and individual characteristics. In this study, based on a repeated measurement design of three sequential measurements at baseline, acute phase and chronic phase, we evaluated the effect of BMI, smoking and drinking on a number of physiological responses in high altitude acclimatization by using mixed model and partial least square path model on a sample of 755 Han Chinese young males.