Nothing in medicine makes sense…

“Nothing in biology makes sense except in the light of evolution.”
— The title of a 1973 essay by theistic evolutionist Theodosius Dobzhansky [fulltext]

The same can, and should, be said of medicine. However as Catriona MacCallum notes:

It is curious that Charles Darwin, perhaps medicine’s most famous dropout, provided the impetus for a subject that figures so rarely in medical education…

Yet an understanding of how natural selection shapes vulnerability to disease can provide fundamental insights into medicine and health and is no less relevant than an understanding of physiology or biochemistry.
— MacCallum CJ (2007) Does Medicine without Evolution Make Sense? PLoS Biol 5(4): e112 doi:10.1371/journal.pbio.0050112

When I began studying medicine I was surprised by the near-complete absence of evolution from the curriculum of my medical school (which gives a certain irony to this article by the former Dean of the selfsame medical school…). Only when I read Randolph Nesse and the late George C. Williams fascinating book, ‘Why We Get Sick‘ (1994) did I began to appreciate the profound importance of an evolutionary approach to human health and disease. I commend their ongoing efforts to make evolutionary biology one of the basic sciences of medicine, as exemplified by their Science editorial, ‘Medicine needs Evolution‘, and a paper titled ‘The Great Opportunity’ published in Evolutionary Applications. Hopefully the profile of evolutionary medicine will soar following the The Lancet‘s special issue commemorating both the 200th anniversary of the birthday of Charles Darwin and the 150 years we have been the fortunate recipients of his greatest gift, ‘On the Origin of Species’…

An evolutionary approach to illness and disease studies not the evolution of the disease but the design characteristics that make us susceptible to the disease.

— Nesse R and Williams GC (1994) Why We Get Sick: The New Science of Darwinian Medicine. New York: Vintage Books.

I now turn to Paul Ewald – speaking at TED – for a demonstration of how an evolutionary approach leads to a deeper understanding of infectious diseases, and offers hope for how they may be controlled.

But evolution is is not only relevant to infectious diseases and antibiotic resistance (which is really “evolution by any other name”). An evolutionary approach brings new understandings and insights to countless aspects of health and medicine, including:

• the adaptive origins of psychiatric illness – e.g. depression [fulltext]
• why we age – e.g. the “antagonistic pleiotropic” theory of aging [pdf]
• cancer as an evolutionary process [pdf]
• the persistence of genetic diseases such as sickle cell anaemia – e.g. heterozygote advantage.
• why we are susceptible to “lifestyle diseases” – e.g. “the thrifty gene hypothesis“.
• the adaptive value of morning sickness during pregnancy [pdf ]
• the rise of allergies and autoimmune diseases since the advent of improved sanitation – e.g. “the hygiene hypothesis“.

To find out more visit the Evolution & Medicine Network and read about ‘the ten categories of evolutionary applications in medicine‘ (pdf).

I shall end with the oft-quoted and poetic close to the first edition of the most important book ever written:

There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.

— Darwin, C R (1859). On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 1st edition, 1st issue. <The Complete Work of Charles Darwin Online>