Evolutionary physiology of tissue oxygenation in mammals

哺乳动物组织氧合的进化生理学

• 批准号: 2112841
• 金额: --
• 依托单位: University of Liverpool
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2112841
• 关键词: Evolutionary; physiology; tissue; oxygenation; mammals

Use of oxygen is one of the most fundamental prerequisites of mammalian life. Yet there is remarkable variation in the details of how they deliver it to their tissues - and there are serious gaps in our understanding of this variation. This project aims to address these unanswered questions. Mammals show a surprisingly high variability in oxygen supply mechanisms, such as differences in blood oxygen affinity, erythrocyte volume- and ion-regulation, haemoglobin aggregation tendency, retinal and placental vascularisation patterns, and adult versus foetal haemoglobin oxygen binding properties. Some of these traits are further linked to genetic polymorphisms and are of great interest to veterinarians and comparative physiologists. Yet their underlying causes have largely remained unexplained. The aim of this project is to analyse the distribution and trace the evolution of these traits on a time-calibrated mammalian phylogeny to increase our understanding of factors that may have shaped their current physiological diversity. Taking advantage of the recent improvements in our understanding of the evolutionary relationships of mammals and the comparative method in evolutionary biology, a number of possible factors will be assessed that may underpin the observed differences in mammalian blood and tissue oxygen supply mechanism. These factors include changes in atmospheric oxygen levels over the last 250 million years, parent-offspring conflict, evolutionary changes in metabolic rate due to altered activity life styles, scaling effects with body mass, and reduced oxygen availability in high-altitude or subterranean niches. Other traits, like altered erythrocyte ion compositions and haemoglobin aggregation tendency, may have repeatedly evolved for blood parasite defence. Understanding selection pressures and molecular mechanisms that have shaped the diversity of mammalian oxygen supply mechanisms (from globin genes to mammalian communities) may help identifying predispositions and constraints for adapting to future environmental change, which will directly affect the dynamics of biodiversity.

氧气的利用是哺乳动物生命最基本的先决条件之一。然而，在它们如何将其传递到组织的细节上存在着显著的差异--我们对这种差异的理解存在严重差距。该项目旨在解决这些悬而未决的问题。哺乳动物在供氧机制上表现出令人惊讶的高度可变性，例如血氧亲和力、红细胞体积和离子调节、血红蛋白聚集趋势、视网膜和胎盘血管形成模式以及成人和胎儿血红蛋白氧结合特性的差异。其中一些特征进一步与遗传多态有关，并引起兽医和比较生理学家的极大兴趣。然而，它们的根本原因在很大程度上仍未得到解释。这个项目的目的是分析这些特征在时间校准的哺乳动物系统发育上的分布和进化，以增加我们对可能形成它们当前生理多样性的因素的理解。利用我们最近对哺乳动物进化关系的理解和进化生物学中的比较方法的进步，将评估一些可能的因素，这些因素可能支持所观察到的哺乳动物血液和组织供氧机制的差异。这些因素包括过去2.5亿年来大气氧气水平的变化，亲子冲突，由于活动生活方式的改变而导致代谢率的进化变化，随体重的变化而变化的影响，以及高海拔或地下壁龛中氧气可获得性的减少。其他特征，如改变的红细胞离子组成和血红蛋白聚集倾向，可能反复进化来防御血液寄生虫。了解形成哺乳动物供氧机制多样性的选择压力和分子机制(从珠蛋白基因到哺乳动物群落)可能有助于确定适应未来环境变化的倾向和制约因素，这将直接影响生物多样性的动态。