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What do Charles Darwin, wisdom teeth, and cancer have in common? They are all related to an emerging field called evolutionary medicine, the application of evolutionary principles to understanding why and how organisms get sick. Scientists in the field believe that an evolutionary perspective can help improve our diagnosis and treatment of disease.

In his keynote address at the inaugural meeting of the International Society for Evolution, Medicine, and Public Health (held March 19-21 in Tempe, AZ), Dr. Harvey Fineberg stated that an understanding of evolution is central to health. Fineberg, the former Dean of the Harvard School of Public Health, argued that an evolutionary viewpoint is necessary to explain structures and functions of the human body (like the fact that wisdom teeth were helpful in some way to our ancestors but serve no purpose now) and evolution can provide insight into diseases that develop and spread under evolutionary mechanisms, like infectious disease and cancer.

Antimicrobial resistance occurs when bacteria, viruses, and other infection-causing microorganisms evolve and develop mutations that enable them to resist drug therapies. Drug-resistant bacteria alone affect over two million Americans each year, according to the CDC. The process of microbial evolution follows the guiding principles of natural selection, so scientists can use their knowledge of evolution to understand how microbes attain resistance and perhaps even prevent it. For example, the current methods of treating bacterial infections target a mechanism of mutation called de novo mutation, but scientists have learned that antibiotic resistance mostly develops from a different method called horizontal gene transfer (Sterns, 2012), which suggests that we may need new therapies for bacterial infection.

Bacteria, like the mycobacteria above that cause tuberculosis, develop drug resistances by evolving and mutating under the influence of natural selection, just like all other organisms. Image source: CDC

Evolutionary medicine has also started to play a role in cancer research. Some scientists are using an evolutionary background to understand how cancers develop, spread, and metastasize as well as to find effective treatments. For instance, a group of scientists is trying to understand how large animals with long lifespans, like the blue whale, have evolved and developed cancer suppression techniques that are reportedly 1000 times better than those of humans. Many hypotheses attempting to explain this phenomenon exist: the lower metabolic rate of large animals might lead to a lower mutation rate, or perhaps tumors are so much bigger in large animals that they are actually less likely to become malignant than smaller tumors (Nagy et. al., 2007). Whatever the explanation, understanding why and how large animals evolved to gain such effective tumor suppressor mechanisms could provide new therapies for cancer in humans. (Caulin and Maley, 2012.)

Additionally, studying deviations from physiological homeostasis in an evolutionary light may suggest that we need to make changes in how we treat some conditions. As Dr. Joe Alcock of the University of New Mexico commented at the ISEMPH meeting, what is defined as “normal” for the human body may be different depending on the conditions. For instance, doctors typically test patients for normal levels of hemoglobin (the molecule that transports oxygen in the blood) and glucose. But evolution has led some populations to adapt to unique environments and develop abnormal levels of these molecules; those living at higher altitudes are found to have a higher base level of hemoglobin than normal, pregnant women exhibit lower concentrations of hemoglobin as an adaptation to pregnancy, and patients with sepsis, a severe complication of infection, have elevated glucose levels, which may be an adaptive survival response. When doctors detect these abnormal glucose and hemoglobin levels, they will often treat the patients to return them to normal; however, Alcock argues that trying to restore every patient to one standard level may in fact do more harm than good if deviation from normalcy has an adaptive purpose.

The growth in the field of evolutionary biology, along with the sharp decline in genome-sequencing costs, has led to a new discipline of treating and diagnosing diseases called phylomedicine (Kumar et. al., 2011). Studying the differences between genomic information of healthy and diseased people, scientists have discovered many genetic diseases and the DNA variations associated with them. For example, mutations in the ALDH1L1 gene are associated with an increased risk of stroke (Williams et. al., 2014). However, simply analyzing individual genomes to discover the variations linked with certain diseases is inefficient and produces an extremely high volume of data, not all of which are significant. Instead, scientists can combine this analysis with a multi-species evolutionary perspective to narrow down the list and determine which genetic markers are associated with disease. Once these markers, like the ALDH1L1 gene, are identified, we can use them for diagnosis and as potential therapeutic targets.

Evolutionary principles can give insight into a wide range of medical topics: besides cancer and infectious disease, evolutionary thinking has shed light on other diseases like jaundice, influenza, and mental disorders (Nesse and Stearns, 2008). Also, studying the timeline of animal evolution and trait development can tell us which animals are most accurate models of human physiology for drug and device preclinical testing.

Members of the discipline see evolutionary medicine as having the potential to revolutionize the way we think about medicine. Adopting a new, evolutionary viewpoint on some of our most complex diseases could greatly benefit patients.

In our next post, we’ll go into more detail about a specific clinical application of evolutionary medicine. Is there a topic you’d like to hear more about? Let us know in the comments section.

This series is supported by NSF Grant #DBI-1356548 to RA Cartwright.

I am sure we all read it in the papers several weeks ago: Two-thirds of all cancers are caused by bad luck. The New York Times said so. Science magazine, which published the original article said so too.

Only problem, the original article did not say that, and to her credit, Jennifer Couzin-Frankel, the Science reporter who “said so too,” corrected the record in a sort of meditation on the difficulty of getting difficult scientific concepts correct while working on deadline.

In fact, the authors did not say that “[r]andom mutations may account for two-thirds of the risk of getting many types of cancer, leaving the usual suspects—heredity and environmental factors—to account for only one-third, …” as the Times put it. What they said was more subtle, that two-thirds of the difference in cancer rates between different tissues could be explained by random bad luck. That is, “[s]ome tissues are overtaken by cancer more readily than others, and mutations accumulating in stem cells explained two-thirds of that variability,” in Couzin-Frankel’s words.

It is good to know that Science is self-correcting.

Fecal transplants no joke


Before writing this article, I confess I went to the Web and Googled “fecal transplant joke” but, alas, all I could find were sentences like, “Fecal transplants are no joke.” No, they are not, but could we not expect at least a modicum of childish humor?

An article, The promise of poop, in Friday’s Science magazine discusses the medical possibilities of fecal transplants. As far as I know, these were first considered as a last-ditch treatment for Clostridium difficile infections, which are very severe intestinal infections and come about when antibiotics kill the great majority of the other floras in the large intestine. A hospitalist in a long-term care facility told me a couple of years ago that he thought fecal transplants would become the treatment of choice for “C-diff.”

By James DeGregori and Michael Antolin

The journal Evolution: Education and Outreach (EVOO) had dedicated the December issue to evolutionary medicine, with articles on how evolutionary theories are critical for understanding human disease and why thorough classroom instruction in evolution is essential. The publisher Springer has made the journal freely available through the end of December. Many of the articles are written for a broad audience and should be of interest to specialists and non-specialists alike.

The special issue was edited by Kristin Jenkins of the National Evolutionary Synthesis Center and Michael Antolin of Colorado State University, and in part follows a symposium organized for the 2011 annual meetings of the Society of the Study of Evolution held June 19 in Norman, Oklahoma. The purpose of that symposium broadly overlaps the EVOO special issue: to make biologists who teach evolution at every level from secondary school to medical school aware of how much biomedical science gains from understanding human evolution and our continued vulnerability to disease. An additional goal is to increase understanding and acceptance of evolutionary science in biomedical research and to help doctors become better practitioners.

Margulis does it again


We all know of once-respected scientists who ended up going off the deep end, adhering to an unproven idea despite massive evidence to the contrary. Linus Pauling and his advocacy of megadoses of Vitamin C, or Peter Duesberg’s descent into HIV denial. It’s all the more disappointing when the one taking a dive is a woman, since there are, compared to men, relatively fewer female “big names” in the sciences. So when one goes from views that were outside of the mainstream (but later proven largely correct) to complete science denialism, it makes it all the more depressing. Even worse, mainstream popular science magazines like Scientific American (with this article by Peter Duesberg) and Discover (Duesberg again) give these ideas reputable press. And now Discover has done it again by giving “maverick” biologist Lynn Margulis a profile in their latest issue. More over at Aetiology.

Columbus (Ohio) Science Pub inaugural event


Dan Siegal-Gaskins (pdf; scroll to page 8), a Postdoctoral Fellow in the Mathematical Biosciences Institute at The Ohio State University, is starting up a Science Pub in Columbus. Science pubs are a kind of Science Cafe. They’re “live events that involve a face-to-face conversation with a scientist about current science topics. They are open to everyone, and take place in casual settings like pubs and coffeehouses.”

The Columbus Science Pub will hold its inaugural event Tuesday September 7 at 7:00 pm in the basement of (what else?) a bar, Hampton’s on King right by the OSU campus in Columbus. (It is a Science Pub, right?)

The speaker will be Tara C. Smith, Assistant Professor of Epidemiology in the College of Public Health at the University of Iowa, Deputy Director of the University of Iowa Center for Emerging Infectious Diseases, founder of Iowa Citizens for Science, author of the Scienceblog Aetiology, and a participant in the Panda’s Thumb field trip to the Creomuseum. Be warned: The announcement on Facebook says “7:00 pm to 2:30 am”!

I’m going to try hard to make it down to Columbus for (some of) the festivities and other Central Ahia folks are cordially invited to join us, so mark your calendars now. I’ll post a reminder a few days before the meeting.

A recurring theme amongst ID antievolutionists holds that evolution really doesn’t contribute useful directions or concepts in the realm of biology or medicine. Philip Skell regurgitates the theme in a recent commentary in Forbes magazine:

“Examining the major advances in biological knowledge, one fails to find any real connection between biological history and the experimental designs that have produced today’s cornucopia of knowledge of how the great variety of living organisms perform their functions. It is our knowledge of how these organisms actually operate, not speculations about how they may have arisen millions of years ago, that is essential to doctors, veterinarians, farmers and other practitioners of biological science.”

And later:

“The essence of the theory of evolution is the hypothesis that historical diversity is the consequence of natural selection acting on variations. Regardless of the verity it holds for explaining biohistory, it offers no help to the experimenter–who is concerned, for example, with the goal of finding or synthesizing a new antibiotic, or how it can disable a disease-producing organism, what dosages are required and which individuals will not tolerate it. Studying biohistory is, at best, an entertaining distraction from the goals of a working biologist.”

The blogosphere (and probably print media) are replete with summaries and specific cases that show Skell’s assertions to be a crock. This essay summarizes one such example. I have chosen this one because it refutes, specifically, the claim that an understanding of the evolutionary history of an organism “offers no help to the experimenter–who is concerned, for example, with the goal of finding or synthesizing a new antibiotic, or how it can disable a disease-producing organism”. It also ties Skell’s uninformed comments in with another subject that causes ID antievolutionists much consternation - the origins and evolution of organelles.

At the Christian Today website we learn how the Creationist in Texas have been defeated, although they did manage to get some amendments approved which undoubtably will be abused by some.

The scientists, apparently familiar with the Discovery Institute’s desperate attempts after the Dover failure, observed that

Over 800 scientists in Texas have signed a statement to “encourage valid critical thinking and scientific reasoning by leaving out all references to ‘strengths and weaknesses’” of evolution - references, they say, that politicians “have used to introduce supernatural explanations into science courses.”

Egnor shoots! He scores!

(another own goal, of course.)

There he goes again. Creationist neurosurgeon Michael Egnor’s latest post over at the Discovery Institute’s Why’s Everybody Always Picking On Me blog may have actually reached a new standard for missing the point. And, as both my loyal regular readers know, that’s not an easy mark for Egnor to hit.

The current contender is his latest post in a back-and-forth that he’s been having with PZ and Orac. Once again, Egnor is attempting to argue that evolutionary biology has not provided any useful insights to the field of medicine. That much is familiar ground. What’s new this time is the hypothetical that he’s dredged up in an attempt to prove his point. His hypothetical is long and involved, which should provide you with your first warning that the argument is perhaps not as sound as he believes:

What I’m arguing is that the truth or falsehood of Darwinian stories is of no tangible value to medicine. Consider the following example.

I would suspect that careful epidemiological studies of the British population would show that the prevalence and incidence of spina bifida increased following World War One. To my knowledge, this has not been investigated, but it would make sense if it were true, for the following reasons:

Britain suffered enormous casualties during the Great War, as did many other European nations. (I’m just using Britain as an example). It has been said, with asperity, that Britain lost a generation of men on the Western Front. Britain suffered 2,300,000 war casualties – forty four percent of mobilized men, with 703,000 men killed in battle or by disease. On just one day – July 1,1916 – 19,240 British soldiers died in the battle of the Somme. The young men who died were the best of their generation – healthy, and by definition capable of meeting the rigorous physical standards required for military service.

Of course, other British men with debilitating genetic disorders, such as men with spina bifida (which renders the afflicted congenitally paralyzed), were not in the trenches that day, because they were physically unfit for military service, or at least service on the front lines as infantrymen. It’s safe to say that military age British men without spinal bifida were at greater risk of death in the war than were military age British men with spina bifida. Whatever the impediments faced by people with spina bifida – and they face many impediments – they were not called to serve and die in the trenches.

Spina bifida would then be a fine example of an environmental adaptation; it was protective against “acute lead poisoning” – protective against being mowed down by German machine gun fire on the Western Front. So, assuming for argument’s sake that my hypothesis about the post-war epidemiology of spina bifida is true, the genes that give rise to spina bifida conferred a selective advantage on young British men in the period 1914 to 1918, and the differential survival (and reproduction) of that age cohort would explain a (hypothetical) increase in the incidence and prevalence of spina bifida in England in the post war period.

Where to begin?

Read more at The Questionable Authority, where comments may be left:

Bless their hearts. The Creationists over at Answers in Genesis are working their perfectly designed fingers to the bone. Blowing the Discovery Institute out of the water by not only publishing a for-realsies science journal (well, at least once), but also performing ‘semi-technical’ research!

Darwin at the Drugstore? Testing the Biological Fitness of Antibiotic Resistant Bacteria

While its just adorable to see them working so hard, their crippled understanding of basic science leaves this semi-technical article completely worthless.

Over at Uncommon Descent, the blog of William Dembski and friends, a contributor has a post up discussing Peter Duesberg’s aneuploidy hypothesis for cancer (which Orac discussed here for more background). The post itself is a bit confusing–it’s titled “When Darwinism Hurts,” and according to the author’s clarification, it’s about “Darwinism” leading us down the wrong path as far as cancer research goes. (Though whether cancer would be due to mutations in specific genes or in chromosomes, it’s still an evolutionary process, but I digress…) To me, anyway, the more interesting portion was in the comments section, where both DaveScot and Sal Cordova imply also that HIV might not cause AIDS; more over at Aetiology.

2007-07_NG_cover.jpgGiven that malaria is more or less the preeminent case of intelligent design in Michael Behe’s The Edge of Evolution, I think everyone would find it interesting to read the July 2007 cover story of National Geographic, which is on malaria and the history of attempts, failures, and hopes of eradicating it. The story focuses on Zambia, where the infection rates are sometimes over 100% (i.e., people are infected more than once a year). I have a somewhat personal interest in this since when I was seven my family went to Zambia for a year, as my dad was on sabbatical. We all took chloroquine weekly – a nasty-tasting drug to a seven-year old, mind you. And despite religiously taking the nasty-tasting drug, I got malaria in the end anyway (the chloroquine-resistant kind, naturally), came down with it on the plane ride back to the states, and then, sick as a dog, I was paraded around undiagnosed before baffled American doctors who had never seen malaria, until someone had the bright idea that maybe I had picked up the most common disease in Africa. More nasty medicine cured it, but that was an early lesson in evolution for me, let me tell you.

The Alliance for Science has put up the final results from their 1st Annual Evolution Essay Contest! Here’s a copy of their press release, in case you didn’t know about it and want to find out more:

High School Student Cites Disease Tracking and Antibiotic Resistance in Winning Evolution Essay

For Immediate Release

May 16, 2007

Arlington, Va. –Why should doctors study evolution? High school students from all over the nation answered this question with an essay in a contest sponsored by the Alliance for Science, a national non-profit that promotes good science teaching.

“The essay contest is part of our effort to bring together scientists, teachers and supporters of science education with the many religious bodies that have found no conflict between religion and science, said Dr. Irving W. Wainer, the chair of Alliance for Science. “Our goal is to reawaken America’s love of science.”

Gregory Simonian, of Los Angeles, CA, an 11th grader at Los Angeles Center for Enriched Studies, won the grand prize for his essay, which cites disease tracking and antibiotic resistance as two important contributions of evolutionary biology to medicine. Simonian will receive a $300 cash prize.

His teacher, Ms. Gloriana Chung, also receives prizes: $250 for classroom use; GeoSpiza, an interactive biology learning program, and a DVD on evolution from the Howard Hughes Medical Institute.

Merve Fejzula, of Garfield, NJ, won second place for her entertaining essay about visiting her doctor’s own waiting room and considering the role of evolution there. Fejzula is a senior at [Enable javascript to see this email address.], in Englewood, NJ. She receives $250; her teacher Ms. Clare Kennedy wins the evolution DVD.

Third Place: Shobha Topgi, Palatine, IL, an 11th grader at Illinois Mathematics and Science Academy wins $150, and teacher Dr. Richard Dods wins the evolution DVD.

Fourth Place: Linda Zhou, River Edge, NJ, 9th grader at the Bergen County Academies wins $100, and teacher Dr. Judith Pinto wins the evolution DVD.

“I hope this contest has helped students see that evolutionary science is not a matter of personal philosophy or worldview,” said Dick Lessard, AfS Essay Contest Director.”It’s hard, evidence-based science that directly affects our lives individually, as well as having major implications for public policy.”

Not half bad, considering we had the idea in late 2006 and threw the contest together at the last minute so as to try and correspond with Darwin Day 2007. A HUGE thank-you to all our donors for making this possible, and remember that this is just the tip of the iceberg! We’ll be back next year with most of the kinks ironed out, and hopefully some great prizes and new twists!

Also, if anybody is familiar with Drupal content management systems and wouldn’t mind offering up a bit of technical advice, please drop me a line at neurotopia AT gmail dot com.

A downside of successful vaccines

A few weeks back during the whole Egnor kerfuffle, I mentioned how important an understanding of evolutionary biology was to many areas of epidemiology, and specifically, for vaccine development and implementation. As one example, I brought up the phenomenon of serotype replacement, which can occur due to the use of what are called “multi-valent vaccines.” Essentially, these vaccines include strains of pathogens which are either the most common, or the most likely to cause disease–thereby protecting individuals from infection with these specific serotypes, but not making the recipient immune to infection with other strains that aren’t included in the vaccine formulation. The concern is, then, that once those types are reduced in the population via vaccination, other serotypes can come along and fill the niche that they’ve vacated. A recent story by Helen Branswell notes that this is exactly what’s happening with pneumococci:

(Continued at Aetiology)

Dr. Michael Egnor, creationist neurosurgeon and Discovery Institute blogger, has a problem. Either he hasn’t figured out that we’re way past April Fools Day, or he has just managed to produce what might just be the single dumbest anti-evolution argument that I have ever seen. We’re talking about a demonstration of absolute, rock-bottom, Kent-Hovind-eat-your-heart-out, triple-distilled essence of pure stupid.

The argument today - and I warn anyone who knows anything at all about evolution to put down all food and drinks right now - is that if evolution was right, we should see some brain tumors acting to make better brains.

No, I’m not joking. That’s his latest argument, in response to a thorough fisking delivered last month by Yale neuroscientist Steve Novella. Brain tumors mutate and are subject to natural selection, so if evolution is correct they should produce better brains:

Read more (at The Questionable Authority):

Creationist brain surgeon Michael Egnor has been busy over the last couple of days, posting first a “response” to Orac’s challenge then a “response” to Mark ChuCarroll’s repeated attempts to explain the concept of tautology to him. There have been several responses to these two posts over at various of the Scienceblogs already - PZ, Orac, Mark, and Kevin have all addressed one or both of Egnor’s latest claims, and all of their responses are worth reading. I’m actually feeling a little left out right now - after all, Egnor still hasn’t deigned to address the two specific examples I presented of cases where natural selection has and is playing a role in public health decisions.

I’m not going to address Egnor’s claims about the role of the design inference in medicine at the moment. The stupidity really does burn, and Orac did a superb job of working through the brain spasms to deal with that post. Kevin and Mark have also done a good job addressing some of Egnor’s claims in the more recent “tautology” post, but I think that there is something that I can add to their responses. An introduction - Dr. Egnor, I’d like to introduce you to Sir Ronald Aylmer Fisher, FRS.

Read more (at The Questionable Authority):

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An ever-deepening Egnorance


By this point, the name Michael Egnor should be familiar to readers of this blog - but if you need a reminder, he’s the neurosurgeon who recently signed on to the staff of the Discovery Institute’s Media Complaints blog. Over the last week or two, Egnor has been trying to convince people that evolution is really not important in any way to medicine.

His last attempt, before today, came less than a week ago, with this spectacular piece of inane argumentation. I responded to the arguments that he made, Orac responded to the arguments he made, Afarensis responded to the arguments he made, Mark responded to the arguments he made, and many other people have also chimed in on the topic. A couple of hours ago, Egnor decided to take another swing at the argument.

Read more (at The Questionable Authority):

…and still more on Egnor

The Michael Egnor article that I blogged about earlier today was a response to an article written by Scienceblogger Mark Chu-Carroll. Mark has has written his own response to Egnor’s latest post (Pigheaded Egnorance, Antibiotic Resistance, and Tautologies). It’s absolutely worth going over there and giving it a read.

While you’re there, you might also want to take a look at this post by Afarensis and this one by Orac, both of which address the Egnorance of yesterday.

Comments may be left at the home blog for each of those posts.

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