Alison Murray

Summary: 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. My research takes a new approach to understanding how locomotor and energetic selection pressures have shaped modern human diversity and sexual dimorphism, by combining engineering-based musculoskeletal modelling with laboratory- and field-based experimental analyses with athletes. In doing so, this work will: 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. By directly linking sex-specific phenotypic variation with its kinematic and energetic consequences, we will gain unprecedented insight into how modern human diversity has been shaped by the environments in which we have lived, moved, and adapted. 

Collaborators: Dr. Josh Giles (UVIC), Dr. Jonathan Wells (UCL)

Project dates: current-2026

Seeking PhD students interested in these or related projects to join our team for Fall 2022 start. If interested, please contact Dr. Alison Murray at amacintosh@uvic.ca

This project seeks to better understand limb bone anterior curvature in the archaeological record,  and its potential relationships with walking in uneven terrain, by applying engineering-based musculoskeletal (MSk) biomechanical modelling techniques to three-dimensional laser scan models of curved vs. straight thigh and shin bones from archaeological collections. We

investigate the effects of variation in bone curvature on muscle and joint forces in the leg experienced during walking compared to a proxy for walking in a mountainous region: stair-climbing. Results may aid in better understanding the biomechanics of curvature in the archaeological record, particularly among populations living in mountainous terrain, and what this variation means about habitual behaviour and mobility in human evolution.

Relative to other species, humans are characterised by considerable biological diversity despite genetic homogeneity. This diversity is reflected in skeletal variation, but we lack sufficient understanding of the underlying mechanisms to adequately interpret the archaeological record. My research comprises part of the larger ADaPt project (Adaptations, dispersals, and phenotype), a five year project funded by the European Research Council, to improve our understanding of the origins of human variation in the past. It does so by:

1) documenting and interpreting the pattern of global hunter-gatherer variation relative to genetic phylogenies and climatic variation;

 2) testing the relationship between environmental and skeletal variation among genetically related hunter-gatherers from different environments;

 3) examining the adaptability of living humans to different environments, through the study of energetic expenditure and life history trade-offs associated with locomotion; and

 4) investigating the relationship between muscle and skeletal variation associated with locomotion in diverse environments.

The research combines detailed study of the global pattern of hunter-gatherer variation in the Late Pleistocene and Holocene with ground-breaking experimental research which tests the relationship between energetic stress, muscle function, and bone variation in living humans. The first component tests the correspondence between skeletal variation and both genetic and climatic history, to infer mechanisms driving variation.

My research makes up the second component, which integrates this skeletal variation with experimental studies of living humans to, for the first time, directly test adaptive implications of skeletal variation observed in the past. The ADaPt project provides the first links between prehistoric hunter-gatherer variation and the evolutionary parameters of life history and energetics that may have shaped our success as a species.

To address the research questions of the second component of the ADaPt project, I study skeletal morphology, muscular variation, and physiology and adaptive tradeoffs among living athletes and recreationally-active non-athletes. My past projects with ADaPt include the use of CT imaging, force plate mechanography, and 3D body scanning to investigate the relationship between mechanical loading, soft tissue, and skeletal variation among women. The ultimate aim of this project was to enhance our understanding of the mechanisms influencing bone mass and distribution among women and enable more accurate behavioural reconstruction in the past. My ongoing projects test the relationships between performance, climate, and variation in physique, energetic expenditure, and physiology among living human ultramarathon runners racing in extreme conditions around the globe. These data are then combined with laboratory based study quantifying variation in aerobic performance, muscle function, phenotype, and bone structural properties in these ultramarathon runners. This combination enables the direct testing of the energetic implications of skeletal and muscular variation associated with locomotion in diverse environments.

www.adaptproject.eu  

2003- Murray A, MacKinnon M, Carswell TMR, Giles JW. Anterior diaphyseal curvature of the femur and tibia has biomechanical consequences during unloaded uphill locomotion. Frontiers in Ecology and Evolution Volume 11-2003

2022- Murray A. Variability and the form-function framework in evolutionary biomechanics and human locomotion. Evo Hum Sci 4:e129.

2021- Murray A, Erlandson M. Tibial cortical and trabecular parameters together can pinpoint   the timing of impact loading relative to menarche in premenopausal females. Am J Hum Bio 2021:e23711.

2021- Longman DP, Murray AA, Roberts R, Oakley S, Wells JCK, Stock JT. Energetics as a driver of human morphological thermal adaptation; Evidence from female ultra-endurance athletes. Evol Hum Sciences. 3:e22

2020- Murray AA, Stock JT. Functionally-related muscle force interacts with stature to influence polar second moments of area in the lower limb among adult women. Am J Phys Anthropol.

2019- Longman DP, Murray AA, Roberts R, Oakley S, Wells JCK, Stock JT. Ultra-endurance athletic performance suggests energetics drive human morphological thermal adaptation. Evol Hum Sciences. 1:e16

2019- Macintosh AA, Stock JT. Intra-limb variation in lower limb bone functional adaptation to loading among living women: Implications for identifying locomotor variation in the past. Am J Phys Anthropol 168:566-581

2018- Macintosh AA, Wells JCK, Stock JT. Maternal investment, maturational rate of the offspring, and mechanical competence of the adult female skeleton. Evol Med Public Health 2018:167-189.

2018- Payne S, Kumar BC, Rajendra, Pomeroy E, Macintosh AA, Stock JT. Thrifty phenotype vs cold adaptation: Trade-offs in upper limb proportions of Himalayan populations of Nepal. Royal Soc Open Sci 5:172174.

2018- Payne S, Macintosh AA, Stock JT. The influence of digit proportions on dexterity during cold exposure. Am J Phys Anthropol 166:875-883.

2018- Payne S, Macintosh AA, Stock JT. The thermoregulatory function of the human hand: How do palm and digit proportions affect heat loss? Am J Phys Anthropol 166:803-811

2018- Payne S, Macintosh AA, Stock JT. Body size and body composition effects on heat loss from the hands during severe cold exposure. Am J Phys Anthropol 166:313-322.

2018- Pomeroy E, Macintosh AA, Wells JCK, Cole TJ, Stock JT. Relationship between body mass, lean mass, fat mass, and limb bone cross-sectional geometry: Implications for estimating body mass and physique from the skeleton. Am J Phys Anthropol 166:56-69.

2017- Macintosh AA, Pinhasi R, Stock JT. Prehistoric women's manual labor exceeded that of athletes through the first 5500 years of farming in Central Europe. Sci Adv 3:eaao3893.

2016- Macintosh AA, Pinhasi R, Stock JT. Early life conditions and physiological stress following the transition to farming in Central/Southeast Europe: Skeletal growth impairment and 6000 years of gradual recovery. PLoS ONE 11(2): e0148468.

2016- Stock JT, Macintosh AA. Lower limb biomechanics and habitual mobility among mid-Holocene populations of the Cis-Baikal. Quat Int 405B:200-209.

2015- Macintosh AA, Davies TG, Pinhasi R, Stock JT. Declining tibial curvature parallels ~6150 years of decreasing terrestrial mobility in Central European agriculturalists. Am J Phys Anthropol 157:260-275.

2014- Macintosh AA, Pinhasi R, Stock JT. Divergence in male and female manipulative behaviors with the intensification of metallurgy in Central Europe. PLoS ONE 9(11): e112116.

2014- Macintosh AA, Pinhasi R, Stock JT. Lower-limb biomechanics track long-term decline in mobility across ~6150 years of agriculture in Central Europe. J Archaeol Sci 52:376-390.

2013- Macintosh AA, Davies TG, Ryan TM, Shaw CN, Stock JT. 2013. Periosteal vs. true cross- sectional geometry: A comparison along humeral, femoral, and tibial diaphyses. Am J Phys Anthropol 150:442-452.