JAMA published two articles to commemorate Darwin’s 200th birthday.
They illustrate the delicate state of medical knowledge about evolutionary biology. The one by Jim Evans offers a succinct and sophisticated overview of what evolution offers to medicine now. The other illustrates how far we have yet to go.
The burgeoning recognition of evolutionary biology’s importance to medical science would have delighted Darwin, who as a teenager rounded with his father, an admired Shropshire physician. In fact, Darwin studied medicine in Edinburgh, Scotland, until his squeamishness toward the barbarous nature of that era’s medical practice and his zeal for natural history lead him to flee the medical field. But Darwin recognized that the human body can be understood at a fundamental level only by an exploration of its evolutionary past. Just as the study of political history is necessary to understand how societies have arrived at their present state, evolution illuminates the deep history of the human body that makes sense only in light of that history. Nevertheless, medicine and evolutionary biology seemed to follow separate trajectories for a considerable time after the publication of On the Origin of Species.3 However over the past decade, physicians have begun to perceive the relevance of Darwin’s work with the growth of an extensive contemporary literature focusing on evolutionary medicine. This new approach to medicine promises cogent explanations for and new approaches to such diverse phenomena as aging, obesity, diabetes, low back pain, and cancer.4–6
The other paper 200 Years After Darwin (link and excerpts below) is admiring of Darwin, but the paper is only about genetics, not evolution. It describes the disappointment of genome wide association studies, but does not mention the good evolutionary reasons why such studies have failed to find genes of large effect for common diseases.
Worse yet, it makes elementary mistakes.
“natural selection functions only before or during the reproductive years and not afterward”
–However, actions after menopause can influence fitness via kin selection.
“The major biological function of natural selection is to select for fitness, allowing for reproduction and maintenance of a lineage or species”
–This correctly identifies the role of reproduction, but it accepts naive group selection.
“perhaps evolution has actually selected for aging and neurodegenerative diseases as a means to maintain the limits of a finite lifespan”
–Group selection again, and no link to the large literature on the evolutionary explanations for senescence.
This paper, published 150 years after The Origin, is laudable for its enthusiasm for evolutionary ideas and Darwin, but it also illustrates that many otherwise excellent scientists and editors have not had a chance to learn about modern evolutionary biology and its applications in medicine. As the saying goes, further work is needed.
Two hundred years after Darwin’s birth, molecular genomic analyses of the human genome have been implemented, seeking the genetic basis for natural selection providing biological fitness and also risk of developing disease. Genome-wide association studies (GWASs) seeking gene variations, or single-nucleotide polymorphisms (SNPs), causal of several human diseases have been conducted in recent years. These diseases include autism, schizophrenia, obesity, diabetes, and heart disease.
Then there is the issue that natural selection functions only before or during the reproductive years and not afterward, when AD and Parkinson disease occur. The major biological function of natural selection is to select for fitness, allowing for reproduction and maintenance of a lineage or species. Aging and neurodegenerative diseases seem to have escaped the forces of natural selection by occurring after the reproductive years. On the other hand, perhaps evolution has actually selected for aging and neurodegenerative diseases as a means to maintain the limits of a finite lifespan.