Embracing a Fuller History of the Application of Evolution to Medicine

In a recent blog post (http://evmed.asu.edu/blog/evolutionary-medicine-top-ten-questions), Randy Nesse suggests that the presentations and discussions at the second annual conference of the International Society for Evolution, Medicine, and Public Health (ISEMPH) were

“… instigated 25 years ago as George Williams and I discussed and grappled with how evolution could be useful for medicine, and what to call the enterprise.”

In her chapter (Bentley, 2016) introducing the just published book, “Evolutionary Thinking in Medicine: from Research to Policy and Practice,” the author acknowledges activity that can be considered evolutionary medicine in the years prior to 1991 but confines it to before roughly 1940.  Following the end of World War II, Professor Bentley finds little to no evidence of significant work in the field until the 1990s.  Unfortunately, these claims disregard substantial numbers of evolution-related studies that either influenced fundamental understanding of human health and disease or affected medical practice. (more…)

An Evolutionary Link between Cancer and Scleroderma: Somatic Cell Variation and Selection

Geneticists have recognized for some time that many genes exhibit pleiotropy, meaning that one mutation can manifest in two or more distinguishable phenotypic effects. In a fascinating study recently published in Science [2014 Jan 10;343(6167):152-7. doi:10.1126/science.1246886], Joseph et al. offer evidence for an example of pleiotropy in which the distinct phenotypic effects associated with mutation of the POLR3A gene, which encodes a subunit (RPC1) of RNA polymerase III, are associated with two different diseases: one or another form of cancer and an autoimmune disease (scleroderma). (more…)

Teaching the Relevance of Evolution to Understanding Immune Recognition

Last month, I completed teaching a graduate course for the tenth time.  After several years (in the early 1990’s) of thinking about launching a new alternate-year seminar course and then planning it, I began teaching PATH 480 in the fall of 1994.  The original name of the course, maintained through the first seven times I taught it, was: “Immunology, Evolution and Logic.”  Beginning in 2009, another faculty member, Derek Abbott, joined me in teaching the course, and the title was revised to: “Logical Dissection of Biomedical Investigations.”  In my portion of the course, I retained an emphasis on the relevance of logic and evolutionary principles to thinking about immune recognition and immune functioning more generally.  I focused class sessions on concepts and underlying assumptions critical to experimental investigations as well as on experimental design and data interpretation in articles reporting studies pertaining to immune recognition. Dr. Abbott has focused his portion of the course on the practical cognitive skills involved in reviewing papers and grant proposals pertaining primarily to innate immune signaling. (more…)

The Case for Applying Negative Selection to Thoughts on Clonal Selection by Prospect Magazine’s Number One 2013 “World Thinker”

Currently, I am on vacation near the beach in South Carolina.  Consequently, I have opted for a topic that is bit different than the majority of my monthly commentaries in that it focuses not on a recent original report but instead on a conceptual point made in a book over thirty years ago.  Nevertheless, after a somewhat less strictly scientific diversion I will come to the central idea at issue, which is arguably the premier exemplar of the relevance of evolutionary principles to the operation of the immune system on short time scales, by which I refer to the concept of clonal selection.  But first, we make a foray into the world of magazine publishing and the niche within that domain focusing on the arguably more intellectual readers. (more…)

The disappearing human microbiota

What are the consequences of the disappearing human microbiota?
by Martin J. Blaser and Stanley Falkow
in Nature Reviews Microbiology   doi:10.1038/nrmicro2245

Who are we? From prions and organelles up through neighborhoods and nation-states, we are groups of groups of groups. In this thoughtful, provocative paper Blaser and Falkow remind us that 90% of our cells are non-human. Vertebrates coevolved with vast communities of microorganisms with whom they share complex endosymbiotic relationships. The authors assert that the human microbiome has been dramatically altered by changes in human ecology. They expand on their disappearing microbiota hypothesis, using the decreasing prevalence of Helicobacter pylori as an example, and argue that such alterations have physiologic and clinical consequences that must be better understood.

Mark D. Schwartz, MD
Associate Professor of Medicine
NYU School of Medicine

Humans and our ancestors have evolved since the most ancient times with a commensal microbiota. The conservation of indicator species in a niche-specific manner across all of the studied human population groups suggests that the microbiota confer conserved benefits on humans. Nevertheless, certain of these organisms have pathogenic properties and, through medical practices and lifestyle changes, their prevalence in human populations is changing, often to an extreme degree. In this Essay, we propose that the disappearance of these ancestral indigenous organisms, which are intimately involved in human physiology, is not entirely beneficial and has consequences that might include post-modern conditions such as obesity and asthma.