EVOLUTIONARY MECHANISMS OF AGE-RELATED BONE LOSS ACROSS THE HUMAN AND HOMINID SKELETON

Age-related bone loss in humans is widely documented and linked to the process of skeletal gracilization, evolved over the last 10 kyrs. One explanation for the human susceptibility to bone loss during ageing is that osteoporosis is an unintended consequence of otherwise advantageous evolutionary adaptations. However, the deeper evolutionary roots and potential epigenetic changes that underlie the biological mechanism of age-related bone loss in humans compared to other hominids are still not understood. Osteoporosis is indeed a global health issue affecting millions of people worldwide with greater prevalence in post-menopausal women. Despite the clinical and biosocial implications of the disease that particularly impact public health issues related to women’s lives, an understanding of the evolutionary roots of osteoporosis is conspicuously lacking. STAND UP aims to fill this gap by identifying and quantifying patterns of age-related bone loss across the skeleton in humans and a comparative sample of our closest relatives, chimpanzees and gorillas, and identifying its epigenetic correlates across taxa. This project will take a novel, comparative and interdisciplinary approach by combining (1) a holistic investigation of the skeletal changes in internal and external bone morphology across the skeleton in unique skeletal samples of humans, chimpanzees and gorillas that each come with critical, individualized demographic and behaviour data, and (2) a comparative molecular analysis of epigenetic bio-markers that underpin patterns of skeletal aging. Ultimately, STAND UP will combine functional morphology of the skeleton, molecular biology and evolutionary anthropology, together with expertise in clinical medicine, to clarify how and why bone structure changes through adult age, particularly in females, in hominids. This project offers an understanding of genotypic-phenotypic underpinnings of osteoporosis in human evolution with far-reaching biological implications.