Experimental approaches to understanding the evolution of human phenotypic diversity

了解人类表型多样性进化的实验方法

• 批准号: RGPIN-2021-02442
• 负责人: Murray, Alison
• 金额: $ 2.04万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=743596
• 关键词: Experimental; approaches; understanding; evolution; human

Modern humans vary in observable characteristics (phenotype) like body size/breadth, limb proportions, body composition, and musculoskeletal traits, yet we are all extremely genetically similar, creating a compelling paradox of particular interest for understanding human evolutionary history. The key to unlocking this paradox is in understanding the mechanisms shaping human plasticity; plasticity is the keystone of the human adaptive response, allowing phenotype to be sensitively adjusted to environmental stresses much faster than is possible through genetic adaptation alone. Some of these stresses stem from balancing the costs of locomotion and thermoregulation in a given environment, both being energetically expensive functions that are critical for survival. Biological anthropologists traditionally use simple models to link phenotypic variation to locomotor costs when moving over flat, open terrain and thermoregulatory costs at rest. However, global patterns do not always match what would be expected based on these simple models. In reality, selection pressures shaping locomotor morphology are complex and vary in relation to multiple environmental factors like vegetation and terrain, and sex-specific factors like the costs of reproduction and load-carrying; none of these have been adequately incorporated into the biomechanical and energetic models on which biological anthropology has traditionally relied. My proposed research represents a transformative new approach to understanding how locomotor and energetic selection pressures have shaped modern human diversity and sexual dimorphism. This work combines engineering-based musculoskeletal modelling with laboratory- and field-based experimental analyses with athletes in order to: i) directly test sex-specific relationships between human phenotypic variation, locomotor costs, and gait kinematics in different environmental conditions, ii) computationally model whether or not variation in skeletal traits typically used to infer behavioural differences between past populations actually produces meaningful adaptive kinematic benefits, and iii) test the extent to which prolonged locomotion-related energetic stress may have contributed to the evolution of sex differences in body composition. In doing so, I will directly link sex-specific phenotypic variation with its kinematic and energetic consequences and offer unprecedented insight into how modern human diversity has been shaped by the environments in which we have lived, moved, and adapted.  The proposed research will also provide crucial sex-disaggregated data to fields in which females are often underrepresented in research. Further, the custom computer modelling methods developed and real-time motion data collected will enable the construction of gait simulations that better incorporate inter-individual variation and help inform the design of customized assistive solutions for individuals with physical and/or locomotor challenges.

现代人类的可观察特征（表型）各不相同，例如身体大小/宽度、四肢比例、身体成分和肌肉骨骼特征，但我们在基因上都极其相似，这创造了一个令人信服的悖论，对于理解人类进化史特别感兴趣。这个悖论在于理解塑造人类可塑性的机制；可塑性是人类适应性反应的基石，使表型能够比仅通过遗传适应更快地敏感地调整环境压力，其中一些压力源于平衡成本。生物人类学家传统上使用简单的模型将表型变异与在平坦、开阔的地形上移动时的运动成本和静止时的温度调节成本联系起来。并不总是符合基于这些简单模型的预期。实际上，塑造运动形态的选择压力是复杂的，并且与多种环境因素（如植被和地形）以及特定性别的因素（如繁殖成本）有关。我提出的研究代表了理解运动和能量选择压力如何塑造现代人类多样性和性别二态性的变革性新方法。这项工作将基于工程的肌肉骨骼建模与基于实验室和现场的运动员实验分析相结合，以便：i）直接测试人类表型变异、运动成本和运动成本之间的性别特异性关系。不同环境条件下的步态运动学，ii）计算模型通常用于推断过去人群之间行为差异的骨骼特征的变化是否实际上产生有意义的适应性运动学益处，以及iii）测试长期运动相关的能量压力可能产生的程度在此过程中，我将直接将性别特异性表型变异与其运动学和能量后果联系起来，并提供对现代人类多样性如何受到环境影响的前所未有的见解。拟议的研究还将为女性在研究中代表性不足的领域提供重要的性别分类数据。 此外，开发的定制计算机建模方法和收集的实时运动数据将使我们成为可能。步态模拟的构建可以更好地融入个体间的差异，并有助于为有身体和/或运动障碍的个体设计定制辅助解决方案。