An alarmingly small fraction of physicians are familiar with the concepts of evolutionary medicine. Why? Because evolutionary medicine is rarely included, especially in the form of full courses treating the topic as a basic science, in medical schools. Nearly half, 48%, of North American medical school curriculum deans stated that they “anticipated igniting controversy at their medical school if they added evolution to their curriculum.” Despite this concern, it is crucial that evolutionary medicine be incorporated into a medical school education in order to produce more competent and aware physicians.
The interdisciplinary field of evolutionary medicine makes use of the principles of evolutionary biology to better understand, prevent, and treat disease. While much of medicine centers on proximate causes that explain the immediate mechanisms of dysfunction and disease, the fundamental questions of evolutionary medicine center on the why of mechanisms; the ultimate causes that are the product of a long evolutionary history. These two modes of explanation are not mutually exclusive, and in fact form a more complete picture when used in tandem.
Evolutionary medicine has important clinical applications, but advocates for its inclusion in a medical school curriculum acknowledge that evolutionary knowledge often does not change what a physician does in his or her day-to-day practice. Instead, they hope that evolutionary medicine will help guide research and provide a depth of understanding to organize and synthesize facts. These individuals encourage doctors to refrain from simply carrying out protocols, and instead build a deep knowledge base that informs their decisions. For instance, a lack of understanding with regards to evolutionary medicine leads to misunderstandings on issues such as diet, aging, and the use of medication to block defense responses.
Long-term, according to physicians Dr. Nesse and Dr. Stearns, evolutionary medicine should establish a framework shift away from the fundamentally incorrect metaphor of the body as an intelligence-designed machine, towards a body shaped by selection. After all, “better decisions come from doctors who understand the ecology of immune responses, the evolutionary reasons for polygenic diseases, the phylogeny of cancer cells, and the origin of antibiotics.” Others posit that evolutionary medicine should be on the same platform as physiology or biochemistry, and is no less vital and relevant to a medical education than these fields are. One physician notes, it is “much easier for medics to learn the nerves involved in the brachial plexus (the nerves supplying the arm) if they first understand the origin of the pentadactyl limb.” Still other specialists in the field have conducted their own research to determine why it is, exactly, that evolutionary medicine has been such an overlooked field. Dr. Nesse and Dr. Schiffman conducted a survey of medical school deans in North America and found that a third of deans stated that a “lack of agreement about the relevance of evolutionary biology” makes it difficult to augment its teaching. Dr. Nesse and Dr. Schiffman counter that the solution to this perceived ignorance on the topic is education, and that such sentiments are inevitably expressed by those who have never had a chance to learn evolutionary biology and are surrounded by an utter dearth of specialists in the field on their medical school faculties.
As far as concrete benefits of incorporating evolutionary medicine go, there is no end to the examples of the research taking place at the intersection of evolution and medicine. In the context of infectious disease, antibiotic resistance can be better understood as a consequence of evolution through natural selection. The deleterious effect that antibiotics have on bacteria–killing them–is an environmental pressure, and bacteria that possess a mutation allowing them to survive are the ones that are able to reproduce. Then, they pass the trait on to their offspring, resulting in a fully resistant generation. Fevers, though a hassle, actually function as a defense mechanism. Elevated body temperature helps certain types of immune cells work better, providing a net benefit in fighting off infection. Some other developing applications of evolutionary medicine include a proposition that miscarriages are a mechanism driven by natural selection to detect and reject a fetus likely to succumb to early infection, and a hypothesis that there has been a recent increase in autoimmune disorders and allergies due to the lack of helminth parasites in the gut. A more long-standing application of evolutionary medicine whose successes are a testament to the field’s potential are phylogenetic methods. Evolutionary medicine can be used to determine which strains of a pathogen are most likely to develop in future epidemics, or trace origins of an outbreak. Such techniques have been employed to tie certain cases of HIV back to a specific Florida dentist, falsify the hypothesis that HIV was introduced into Africa via the polio vaccine, and find that the SARS epidemic originated from a corona virus similar to one endemic in bats. In the end, the push to include evolutionary medicine in a medical school curriculum can come to fruition only with the support of the deans of these universities. In the meantime, however, students, faculty, and researchers, can do their best to make the incredible potential benefits known.
Edited by: Amaan Qazi
Illustrated by: Lily Xu