Doctoral Dissertation Research: Oxygen transport and the evolution of high-altitude adaptation in humans

几个人类种群，每个都有不同的历史，在数千年的时间里已经适应了恶劣的高海拔环境。这个博士论文研究项目比较了两个高海拔人群的生理学，并评估了他们在多大程度上适应了相同的环境应激源-低氧。使用相同的方法，在海拔数千英尺的同一海拔上测量相隔数千英里的人群，该项目采取了一种新的方法，通过测量高海拔适应性如何在身体活动期间在人们中发挥作用。这项研究的结果建立在以前关于这一主题的大量研究的基础上，并提供了关于这两个群体的高海拔适应如何有助于他们在低氧环境中长期生存的重要信息。项目调查人员在当地社区提供科学宣传，并将研究参与者的反馈和想法纳入项目。该项目还为来自STEM学科历史上代表性不足的群体的本科生和研究生提供培训。一些高原人群已经在缺氧环境中居住了数千年，促进了与氧气运输和输送相关的生物学方面的稳定进化变化。虽然暴露于相同的选择压力，这些人群表现出一些不同的生理适应，这表明，某些历史偶然性已经形成了不同的轨迹性状进化跨越地理空间和时间。本项目的总体目标是比较在高海拔地区改善氧气输送的机制。本研究测试的中心假设是，一个人群主要通过增加血氧含量来改善氧气输送，而另一个人群主要通过增加血流量来改善氧气输送。该项目使用精细和仔细匹配的协议，采用运动测试，呼吸气体分析和血液学测量，从每个人群中选择70人来验证这一假设。这项研究的结果有助于对人类生物变化与环境压力源的关系进行大量研究，重要的是通过增加高海拔体力活动压力期间氧气输送的角度。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Several human populations, each with distinct histories, have adapted to harsh high-altitude environments over the course of thousands of years. This doctoral dissertation research project compares the physiologies of two high-altitude populations and assesses the extent to which they have adapted similarly or differently to the same environmental stressor – low oxygen. Using the same methods, measured in populations thousands of miles apart at the same elevation thousands of feet above sea level, the project takes a new approach by measuring how high-altitude adaptations work in people during physical activity. The results of the research build on a large body of previous research on this topic and provide important information about how the high-altitude adaptations in both populations have contributed to their survival over time in low-oxygen environments. The project investigators provide scientific outreach among a local community and incorporate feedback and ideas from study participants into the project. This project also provides training for undergraduate and graduate students from groups historically underrepresented in STEM disciplines.Some highland populations have resided in hypoxic environments for thousands of years, promoting stable evolutionary changes in aspects of their biology related to oxygen transport and delivery. Though exposed to the same selective pressure, these populations exhibit some distinct physiological adaptations, suggesting that certain historical contingencies have shaped different trajectories of trait evolution across geographic space and time. The overall objective of this project is to compare the mechanisms of improved oxygen delivery at high altitude. The central hypothesis that this study tests is that one population improves oxygen delivery primarily through increased blood oxygen content, while the other improves oxygen delivery primarily through increased blood flow. Using refined and carefully matched protocols, this project employs exercise testing, respiratory gas analysis, and hematological measurements in 70 individuals from each population to test this hypothesis. The results of this research contribute to a large body of research on human biological variation in relationship to environmental stressors, importantly through the added perspective of oxygen delivery during the stress of physical activity at high-altitude.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.