Medicine and Evolution, part 8: Two major medical misconceptions about evolution parroted by a Professor of Neurosurgery

I'm getting really, really tired of this.

You've all read my rants at the propensity of surgeons who clearly don't have clue one about evolutionary theory spouting off ignorantly about the alleged shortcomings of evolution as a theory while either explicitly or implicitly promoting the pseudoscience of "intelligent design" creationism. I don't think I have to expound much on just how much this phenomenon irritates me other than to repeat my desire to find a more permanent solution to the question of hiding my face in shame over the antics of my fellow surgeons on this. Perhaps it truly is time to get that metal Doctor Doom mask made. Besides hiding my embarrassment over surgeons like, for instance, Dr. David Cook, an orthopedic surgeon whose ignorance about evolution actually infested this blog last month, it would look wicked cool.

Sadly, the latest surgeon to throw his hat into the ring for the honor of being named the surgeon most proudly willing to trumpet his ignorance about evolution to the world in order to willingly serve the interests of the Discovery Institute makes Dr. Cook look like a Professor of Evolutionary Biology in comparison. Well, not really, but at least Dr. Cook had enough common sense to realize when he had had enough whup-ass administered to him and retreated from the battle back to the safety of tepid "debate" with like-minded antievolutionists. No, amusingly and depressingly at the same time, the most prominent and prestigious surgeon yet to have embarrassed himself by spouting ignorant "questions" about evolution along with "teach the controversy" silliness, Dr. Michael Egnor, Professor of Neurosurgery and Pediatrics at SUNY Stonybrook, is as persistent as the proverbial Energizer Bunny. He just keeps going and going and going and going. And, as he does so, he just keeps bringing more and more shame upon his profession--and mine--surgery.

After my jeremiad about Dr. Egnor's proud ignorance about evolution last week, I thought I could leave the topic alone. At least, such was my intent. Really, it was. But Dr. Egnor wouldn't stop. He just had to show up in the comments of Pharyngula to "defend" himself (a comment that the Discovery Institute trumpeted as though Dr. Egnor was actually asking profound questions), leading to more slapdowns by PZ, Mark, Ed, and Joan, as if the slapdowns he had already received from PZ, Ed, and me weren't enough. Truly, Dr. Egnor is either a glutton for punishment, or just too arrogant to realize when he's made an utter fool of himself. Consequently, I'm still irritated enough to take on what's left over. For example, let's look at this comment by Dr. Egnor:

Several of your buddies in the comments section suggested that Darwinism is essential to modern medicine, and imply that my skepticism is tantamount to medical ignorance (not always spelled with an 'i'). Darwinism has nothing to do with modern medicine, but it had a lot to do with medicine in the early 20th century.

Darwinism has scraped against medicine in three ways: Eugenics, bacterial resistance to antibiotics, and the application of taxonomy to medical research. One scrape was hard, two weren't.

Perhaps a fable (not a just-so story!) will illustrate. Imagine that you, P.Z., were a student in 1925. You would study Darwinism fairly intensively as a high school student, undergrad, and med student (it's a hypothetical!). In high school you'd read Hunter's 'A Civic Biology' (unless you lived in Dayton, Tennessee), which taught the Darwinian superiority of the Nordic races and the need to eliminate the lesser races. In college you would take courses on Eugenics (thousands were offered), and learn the application of dog breeding to humans. As a medical student you would be steeped in Eugenic practices. You might do a term paper on Darwin's lament in the 'Descent of Man' (ever heard of the book?) that the smallpox vaccine was regrettable because it enabled the 'weak' to breed, noting that 'no breeder would ever breed from his worst stock'. You would then go off to practice medicine, and join the Eugenic frenzy. Fifty thousand Americans, tagged 'feeble minded' and manifestly poor breeding stock, were sterilized involuntarily. Your Darwinian-Eugenic work would be mainstream medicine, endorsed by all the big guys, except the 'anti-science' types like Chesterton and the Catholics, who kept bleating about human dignity, and your only interruption would be those pesky Germans who kept visiting, and learning from you. Darwinism was absolutely indispensable to Eugenics, and to American medicine (and some continental European medicine) in the first half of the 20th century.

Zoom ahead in time. You, P.Z., are now a pre-med, circa 1990. You never even heard of Eugenics (the Darwin memory hole took care of that). You're sitting in Bio 101, and it comes time to read 'Origin'. 'Descent' is off the reading list. You're not paying much attention. There's a bottled giant cephalopod on the shelf, and it's alluring. When Professor Meyers gets to the chapter in Origin about the pigeons, it's zone-out time. You get to medical school with zero knowledge of Darwinism. Medical school is no help. No one teaches squat about Darwin in med school anymore, and Professor Egnor gets testy every time someone brings it up. Finally, circa 2000, you're practicing medicine, with a 'Darwin hole' in your brain. 'Natural Selection', to you, is something about the MCAT's.

Aaagh! I can't believe he's invoking the whole "Darwinism equals eugenics" canard. That's about as idiotic as it comes. Even if it were true that eugenicists used evolutionary theory to justify their vile activities in the early 20th century and the whole concept of "racial hygiene," it would be irrelevant. Just because some people put a scientific theory to evil use does not say anything whatsoever about whether that scientific theory is valid or not. One might just as well condemn Einstein, Neils Bohr, and all the physicists whose work formed the basis for the construction of the atomic bomb for the use to which their work was put. In actuality, if we look at the biggest, baddest example of eugenics ever, Hitler's Nazi Germany, the justification for "racial hygiene" was couched more in terms of natural law (that the strong should rule over the weak) and the sort of selective breeding that has been practiced by farmers for centuries. (I suggest that Dr. Egnor read Robert Proctor's excellent treatment of the subject, Racial Hygiene: Medicine Under the Nazis for more information.) I would also point out that Hitler, for example, frequently likened Jews to an "infection" of the German Volk and German racial hygiene frequently described the disabled and retarded as "parasitic." Does that mean we should blame Pasteur for Hitler's eugenics? (In actuality, Hitler sometimes likened himself to Louis Pasteur and Robert Koch; he never likened himself to Darwin, as far as I'm aware.) What really worries me about Dr. Egnor is this statement:

Darwinism was the indispensible basis for Eugenics. I teach in the medical ethics course in my medical school. I make sure the students learn about Eugenics, and where it came from. I have a particular distaste for your ideological ancestors.

And:

Regarding your 'Eugenics denial', the link between Darwinism and Eugenics is tight, a matter of historical record. Everytime I hear the trope 'Darwinism is indispensible to medicine', I'm going to stick Eugenics in your face. Darwinism was indispensible to Eugenics, but is indispensible to nothing else in medicine.

Bullshit. Again, eugenics is little more than selective breeding (which farmers have done for centuries, if not millennia) applied to human beings, complete with the "culling" of undesirables from the "herd." True, "social Darwinists" did seize upon on Darwin's theory, as did racial hygienists like Alfred Ploetz, because it was convenient to do so to justify their view of who is "superior" and "inferior" in society, but it is not Darwin's fault that they applied his theory to areas where it was not scientifically appropriate to apply it. In essence, social Darwinists and eugenicists misused Darwin's theory to justify pre-existing racism and bigotry, just as scientific racists before Darwin used other reasoning to justify the "superiority" of their race over another or the "culling of the herd" to "improve the stock" of their people. With respect to humans, selective breeding of slaves existed long before Darwin, and these slaves were taught that their "rightful place" was to be little more than animals to be used and bred as their masters saw fit. People have long demonstrated racism and a belief that one race is "superior" to another, leading to the subjugation or elimination of races. Also, Thomas Malthus was advocating concepts not unlike those of modern eugenics (his advocacy of eliminating "poor laws," for example) long before Darwin ever published his theory. As early as 1727, the Earl of Boulainvillers tried to argue that French noblemen were the descendants of an original and superior race of Nordic Franks, whereas the lower estates of French society were descended from subjugated Gauls. Heck, if you really want to go far back, the Spartans abandoned male babies considered too sickly or weak to the elements. In fact, eugenics as Dr. Egnor seems to mean the term truly only came into vogue when scientists' understanding of genetics reached a certain point that allowed scientists to understand the genetic basis of disease and other undesirable traits. As Eugen Fischer said in his 1933 inaugural address as Rector of the University of Berlin: "What Darwin was not able to do, genetics has achieved. It has destroyed the theory of the equality of man." Indeed, one might as well blame eugenics on Gregor Mendel, because eugenics and racial hygiene didn't truly ramp up into high gear until our understanding of the genetics and the genetic basis of disease had developed to a certain point!

Worse, Dr. Egnor is teaching his outright misinformation and pseudohistory to impressionable young medical students in medical ethics classes!

But let's look at another of his claims:

Darwinism, understood as the theory that RM+NS accounts fully for biological complexity, doesn't have squat to do with the practice of modern medicine. It's not taught in medical schools, for a reason.

Dr. Egnor is partly correct, but increasingly incorrect. It's true that today, for most physicians, evolution has little or nothing to do with how they practice medicine on a day-to-day basis. However, scientists and physicians are becoming increasingly aware of how evolution influences human susceptibility to disease and how concepts and measurements used to study ecology and evolution at the population level can be adapted to study human disease. Indeed, it's funny that Dr. Egnor should make such a show about misunderstanding and abusing Shannon information theory. It just so turns out that the Shannon diversity index as traditionally applied to the study of evolution in populations was shown to be potentially useful in determining whether a precancerous lesion (Barrett's esophagus) with a high risk of progressing to esophageal cancer is more or less likely to actually progress to cancer in any one individual, as I described in detail nearly a year ago. In brief, the risk of developing esophageal cancer, a particularly deadly type of cancer, correlated highly with a calculated Shannon diversity index calculated on the basis of aspects such as loss of heterozygosity, microsatellite instability, and other genetic markers. Up to 50% of those with a high Shannon index developed cancer, whereas very few of those with low index developed cancer. A second example that I also wrote about in detail nearly a year ago involved used evolutionary theory and genetics to find an unexpected homology between a protein from T. brucei (the trypanosome that causes sleeping sickness) and human proteins that cause diseases in which cilia, the finger-like projections from cells finger-like projections from specialized cells that are involved in cellular motility, absorption, and transport, do not function properly. Finally, Dr. Ivan Schwab, an academic ophthalmologist, has described in considerable detail how evolution can be used in understanding diseases of the eye.

And these are just three examples. There are increasingly many, more. Indeed, even an article ostensibly lamenting how little the term "evolution" is used in the biomedical literature describing the evolution of bacterial resistance to antibiotics shows that the term "evolution" is increasingly showing up in the titles of abstracts and grants. It may take a decade or two for this new understanding of how evolution affects disease susceptibility and how human diseases can be modeled using techniques developed in the study of evolution in populations of organisms to filter out of the cutting edge research laboratories in which it is occurring now, but filter out it will. Fortunately, Dr. Egnor will probably be either retired or nearing retirement when evolutionary medicine reaches its full flower, so that he won't have to trouble his "intelligently designed" mind with learning about it or applying it to his practice.

Let's come back to cancer, though, which is my specialty. (I'm a fellow surgeon, as surgical oncologist, actually, which is why I consider Dr. Egnor's ignorant pontificating about evolution to be a true embarrassment to surgeons everywhere..) Recently, there has been a flurry of interest in how evolution impacts cancer and how evolutionary principles can be applied to cancer. Indeed, we can see this interest in the recent publication of not one but two large review articles on the role of evolution in cancer published in what is arguably the premiere review journal for cancer, Nature Reviews Cancer (ISI impact factor=31.52). The first of these articles appeared in December, entitled Cancer as an evolutionary and ecological process. This article reviewed recent research (including the paper on Barrett's esophagus that I mentioned above) that look at neoplasms as an ecosystem of evolving clones, competing and cooperating with each other and other cells in their microenvironment and how this has important implications for neoplastic progression and therapy. Also, unlike Dr. Egnor, who in his characteristic simplistic fashion, seems to think that natural selection is the be-all and end-all of evolutionary theory (hint: it's not), this article discusses the role of genetic drift, neutral selection, artificial selection, and other mechanisms of evolution in studying cancer. A second article, entitled Darwinian medicine: A case for cancer, appeared in the March issue, hot off the presses. This latter article looks at the broader picture. Rather than discussing modeling cancer as an evolutionary process at the cellular level, this article asks the question: Given that a person's lifetime risk of developing cancer is around one in three. What are the evolutionary mechanisms that have led to the high susceptibility of human beings to cancer? The key argument is that this susceptibility is probably a trade-off between adaptations/mutations that are beneficial to certain aspects of fitness but at the price of susceptibility to malignancies later. Key excerpts:

The essential tenet of the new discipline of evolutionary or Darwinian medicineis that susceptibility to malfunction and disease must in part reflect historical or evolutionary legacies. The corollary is that we might then benefit from stepping back to take a broader look at human history and our protracted evolutionary trajectory. Even a cursory consideration of human anatomy reveals structural imperfections that are pregnant with potential for malfunction. For example, no intelligent designer would place the optic nerve and retina or prostate and urethra in the anatomical relationships in
which we find them. The reality is of course that we have not been 'designed' or 'engineered' at all. The evolutionary processes involved in the diversification of molecules, cells, tissues and physiological processes rely on options generated randomly from previous templates. This is coupled with the selection of beneficial traits, by contingency or chance, or neutral drift. Evolutionary biologists continue to debate the relative importance of the mechanisms of selection, particularly as claims that traits were positively selected (the adaptionist argument) cannot always be substantiated. Irrespective of these uncertainties, the processes involved will inevitably result in 'designs' that have constraints or limitations on board, and trade-offs, collateral damage or negative impacts. Ultimately, inherent flaws are tolerated,
at some level, as long as they do not impact deleteriously on reproductive fitness.

I think that this encapsulates pretty well the misconceptions about evolution that are so prevalent among people like Dr. Egnor. The point is that natural selection works on the basis of "what works today," selecting genetic variants from the limited options available at the time. As Dr. Greaves, the author of the article puts it:

An important consequence of the short-term nature of adaptation by natural selection, other than begetting further selection, is that what emerges from time to time are flagrant mismatches between genotype and environment or genotype and 'lifestyle'. For many species, this will be a wake-up call or farewell.

But does it matter in how we practice medicine and surgery? Dr. Greaves argues that it does now, whether we consciously realize that we are using evolutionary principles or not:

The cancer specialist or pragmatist will still query whether such a view, even if basically sound, contributes anything other than a biological perspective of the origins of vulnerability to cancer. I suggest that it does. First, there can be little doubt that the Darwinian evolution of cancer clones has
huge implications for screening, prognosis and therapy. This has been argued previously, but has only just begun to be taken on board by those involved directly in cancer drug development and treatment. Attributing the special vulnerability of humans to the lethal combination of intrinsic fallibility, chronic mismatches and age is less obviously of practical value, although it does offer a plausible explanation
of a medical conundrum to which a solution is not obvious or perhaps not even possible without the evolutionary perspective. No formal test of the proposition might even be required; we already have adequate evidence from the high cancer rates, in particular those that result from migration or are imposed on other mammalian species by human intervention. At a practical level, this analysis suggests that, for evolutionary reasons, as a species we are inherently more likely to develop cancer than we might like to admit. We cannot reverse our genetic legacies and propensity to cancer, but emphasizing intrinsic vulnerability in this way provides a very strong endorsement of current attempts to combat cancer. These effectively seek to neuter mismatches and minimize the impact of intrinsic risk -- even if the practitioners involved do not realize it.

The bottom line is that Dr. Egnor argues, in essence, that evolutionary theory contributes "nothing" to medicine or to medicine care. To steal another phrase from Curtis Sliwa, he couldn't be more hopelessly wrong. Understanding the evolutionary mechanisms behind diseases or that predispose humans to disease is no different than understanding how antibiotics or chemotherapeutic agents work. It's no different than understanding how β-blockers work. It's the basic science of disease, and it's a basic science that is increasingly resulting in useful new ways of thinking about disease, as in the case of Barrett's esophagus. You can bet that population evolutionary principles will be applied to other cancers; for example, it wouldn't surprise me at all if it's applied to estimating the risk of cancer in colorectal polyps or in the premalignant breast lesion, ductal carcinoma in situ. The bottom line is that Dr. Egnor is a dinosaur. (Well, actually, that's in insult to dinosaurs, who were in actuality very successful, evolutionarily speaking, for a very long time, but you get the idea.) His misunderstanding of evolution and his blithe dismissal of evolution as having zero importance to medicine are truly appalling. It's also becoming increasingly apparent that he's just too arrogant to realize when he is making a fool of himself, which just goes to show that even a Professor of Neurosurgery (as the Discovery Institute likes to repeat over and over and over again to give the false impression that Dr. Egnor has adequate knowledge and training to speak credibly about anything other than neurosurgery) can make an idiot of himself.

It looks as though it's time to order that Doctor Doom mask, at least to wear when I'm among fellow scientists. Of course, the drawback of doing this is that it would likely be seized upon by Dr. Egnor and pro-ID parrots like him as "validation" that those who support evolutionary theory are villains.