Evolutionary Medicine

by

Peter Gluckman, Felicia Low

• LAST REVIEWED: 26 November 2019
• LAST MODIFIED: 26 November 2019
• DOI: 10.1093/obo/9780199941728-0069

Introduction

Evolutionary medicine, sometimes referred to as Darwinian medicine, is an emerging academic field that employs evolutionary principles to aid in the understanding of human health and disease at the levels of both the individual and the population. While its main value lies in giving an ultimate (evolutionary) perspective to patterns of health and disease, there are areas of clinical medicine and public health where it has direct application. Whereas the bulk of clinical medicine is focused on issues of proximate causation and, in particular, pathophysiological mechanisms and their treatment, evolutionary perspectives focus on understanding how and why traits evolved and how they confer greater or lesser disease risk. Evolutionary perspectives also give weight to ecological dimensions, particularly the positioning of individuals within their social and environmental context, and also their relationship to other organisms, including gut microbiota, parasites, and infectious agents. A core principle of evolutionary medicine is that selection has operated to optimize reproductive fitness, and that this is not the same as selection for health or longevity. Indeed, selection pressures wane with age, and humans have had increasing median lifespans in recent centuries, leading to greater incidence of diseases that occur in the post-reproductive period. Another distinctive feature is an appreciation of the role of cultural evolution and technology in changing the environments within which humans now live—changes that can exaggerate the mismatch between evolved biology and the environment, with health consequences. Selection can occur not only at the level of the whole organism but also at the level of a cellular clone, and evolutionary concepts have become important in understanding the progression of cancer. More controversially, evolutionary concepts are contributing to understanding the origin of human behavior at both an individual and a group level, and also to understanding some psychiatric symptomatology. Evolutionary history also contributes to disease risk through anatomical and biochemical vestiges such as the appendix or the lack of the gene to synthesize ascorbic acid (and prevent scurvy); through genetic mechanisms such as founder effects and balancing selection; and through the evolution of defense mechanisms that may operate excessively (e.g., autoimmune disorders), which can explain much common symptomatology (e.g., fever). Being well versed in evolutionary concepts enables medical students and clinicians to integrate factual knowledge of cellular biology, physiology, and anatomy into a meaningful framework, thus promoting a better understanding of human health and disease. This sentiment is being embraced by a growing number of medical schools worldwide as evidenced by the inclusion of evolutionary medicine into the core curricula.

General Overview

The field of evolutionary medicine owes its genesis to Williams and Nesse 1991 and its authors’ subsequent popular science book Nesse and Williams 1994. From this original somewhat adaptationist focus, evolutionary medicine has matured into a more nuanced and complete field through the publication of multiple books, textbooks, review articles, and special journal issues devoted to the field. The textbooks on evolutionary medicine, Gluckman, et al. 2016 and Stearns and Medzhitov 2015, provide comprehensive grounding in basic principles of evolutionary biology of relevance to the medical community and serve as a formal framework through which the impact of evolutionary processes on disease susceptibility can be better understood. Topics covered by edited books, such as Jasienska, et al. 2017 and Brüne and Schiefenhövel 2019, have relatively different emphases and demonstrate well the breadth of the field. The concise volume Perlman 2013 offers case studies of specific diseases. All texts are generally suitable for a broad readership, including researchers in evolutionary biology, medicine, anthropology, and genetics; physicians; (under)graduate students; and medical educators.

• Brüne, Martin, and Wulf Schiefenhövel, eds. 2019. The Oxford handbook of evolutionary medicine. Oxford: Oxford Univ. Press.

  A multi-author book that first provides an overview of evolutionary theory, relevant cellular and molecular mechanisms, growth, nutrition, and aging, then expands on these concepts by relating them to the major organ systems of the human body. The book opens with a very useful and detailed overview by Randolph Nesse.

• Gluckman, Peter, Alan Beedle, Tatjana Buklijas, Felicia Low, and Mark Hanson. 2016. Principles of evolutionary medicine. 2d ed. Oxford: Oxford Univ. Press.

  DOI: 10.1093/acprof:oso/9780199663927.001.0001

  The second edition of the first systematic textbook to comprehensively explain principles of evolutionary biology from a medical perspective to illustrate its utility in medicine and public health. It first lays a strong foundation for basic concepts of evolutionary theory, then uses numerous clinical examples to explicate how an evolutionary perspective can inform the understanding of human health and disease, from infection and cancer through to reproduction and behavior.

• Jasienska, Grazyna, Diana S. Sherry, and Donna J. Holmes, eds. 2017. The arc of life: Evolution and health across the life course. New York: Springer.

  Authored by biological anthropologists, this edited book has a strong emphasis on human life history and trade-offs, with several chapters devoted to the implications for reproduction.

• Nesse, Randolph M., and George C. Williams. 1994. Why we get sick: The new science of Darwinian medicine. New York: Vintage.

  Aimed at the educated layperson, this book was the first accessible primer to the field of evolutionary medicine that proposed largely adaptationist evolutionary explanations for why we are vulnerable to disease. Its popularity was a key factor leading to the development of evolutionary medicine as a research domain in its own right.

• Perlman, Robert L. 2013. Evolution & medicine. Oxford: Oxford Univ. Press.

  DOI: 10.1093/acprof:oso/9780199661718.001.0001

  A short, nontechnical primer. This book has its clinical readership in mind by devoting much attention to specific medical problems, such as cystic fibrosis, aging, cancer, infectious disease, and malaria, and to how medical insight into these diseases can be aided by the application of evolutionary concepts.

• Stearns, Stephen C., and Ruslan Medzhitov. 2015. Evolutionary medicine. Sunderland, MA: Sinauer Associates.

  While more in-depth explanations of fundamental principles of evolutionary biology may be sourced elsewhere (e.g., Gluckman, et al. 2016), this well-illustrated textbook is an engaging read, with specific chapters challenging traditional definitions of patient and disease, and stimulating further critical thinking via provocative “open question.” It is also supported by a series of online lectures (see Evolution and medicine with Stephen Stearns, cited under Journals and Resources).

• Williams, George C., and Randolph M. Nesse. 1991. The dawn of Darwinian medicine. Quarterly Review of Biology 66:1–22.

  DOI: 10.1086/417048

  The first paper to formally link the fields of evolution and medicine in a conceptual framework (the term “Darwinian medicine” was first proposed here).