Of what value is evolutionary biology in medicine?

April 3, 2009 • 9:43 am

I have sometimes written that evolutionary biology doesn’t have much practical value in medicine or other areas impinging on humanity’s material well being.  Here is one example of what I’ve said.  However, my friend and colleague David Hillis at The University of Texas in Austin — who played a big role in trying to make the Texas State Board of Education teach real science —  has taken exception to my view.  I asked him to let me know how he thought that evolutionary biology had been of use in medicine, and he wrote me an email with his answer, which he’s given me permission to post.  He’d wants to emphasize that it’s an off-the-cuff response rather than a comprehensive reply, which of course I appreciate; but I think it’s worth posting:

OK, here are just a few examples from the thousands that are in the literature, off the top of my head:

Using positive selection to identify the pathogenic mechanisms of HIV in humans: PNAS 102:2832-2837 (one of many such studies that are now appearing and are using positive selection in pathogens to identify pathogenic mechanisms).

Using phylogenies and positive selection to predict which currently circulating strains of influenza are most likely to be closely related to future flu epidemics: Science 286: 1921-1925.

Using evolutionary analyses to track epidemics in human populations: many examples that have wider health implications, but our study of transmission in a forensic case was an interesting example with a specific legal application; PNAS 99:14292-14297.

Using evolutionary analyses to identify new disease outbreaks: new examples in every single issue of Emerging Infectious Diseases.

Using phylogenetic analyses to identify whether polio outbreaks are from native circulating viruses or from reverted, escaped vaccines (which tells health workers which vaccines to use in these areas to eradicate disease): see review in Bulletin of the World Health Organization, Vol. 82, No. 1.

Identifying changes in sodium channel genes that are under positive selection for TTX resistance, which has led to understanding the function of human diseases that are caused by the corresponding substitutions in human sodium channel genes: Mol. Biol. Evol. 25(6):1016–1024. (I included this one to show that all of the examples are not from virus work; this is the original evolutionary work from Manda Jost and Harold Zakon, with our collaboration, but there has been follow-up on the understanding of human diseases that are produced from these same mutations, now that they have been replicated by in vitro mutagenesis)

This just scratches the surface. I think there are now more papers that use evolutionary methods and analyses in the human health literature than all other areas of biology combined. I think it is crazy to not acknowledge the numerous and important human health applications of evolutionary theory and methods.


Well, this is good enough for me — I gladly retract my earlier opinion that evolutionary biology hasn’t been of much use in medicine.  Thanks, David.

NOTE:  In the comments to this post, one reader asks whether David’s examples aren’t just genetic, having nothing to do with evolution?  David has posted a response.

29 thoughts on “Of what value is evolutionary biology in medicine?

  1. Playing *serious* devil’s advocate here. I don’t know much about it… but there is a disconnect between creationism-talk and science. They seem to think that when they say “evolution” plays no part in medicine that we know what they mean (which is that the parts of evolution they object to) play no part. They don’t object to new strains of flu, antibiotic resistance through genetic adaptation, etc… they object to different, very loosely-defined, “kinds” being related by common descent. I’m not sure the examples cited here would satisfy them. Not that matters.

  2. At long last!
    Just another example: P.Z. Myers recently posted fascinating comments on cephalopod venoms, based on previous research by Bryan G. Fry.



    The really neat part is to see how relatively common enzymes — say, phospholipases and peptidases — are “recycled” as weapons in the course of evolution.

    The implications for medical research and future therapeutic uses are staggering; also, I daresay, rather self-evident. Just one example of how evolutionary biology is likely to become increasingly significant in medicine.

  3. If they can do all those evolutionary analyses then that argument is demolished.

    Well done. Science has unbounded potential and the creationists should step aside or be mowed down.

    1. James,

      Would you mind explaining how you imbed a hyperlink in your words (as you did with “Mike the …..?”

      What are the pre & postambles that you’re using?

      Thanks for your help.
      ~Rev. El

  4. As a practicing clinician (interventional cardiologist) evolution plays an enormous role in my practice. Simply being aware that humans are an evolved species helps in understanding the interplay between the artificial environment we are in today (civilization) and our evolved biology (hunter-gatherer). This helps in explaining many disease origins and helps direct research and therapy. Animal models in medical research are tremendously important and need to be understood in their evolutionary relationship to us. While these are not direct ties to evolutionary biology, “nothing makes sense in medicine except in the light of evolution”.

  5. In the past, religious objections to discoveries have been broken down by the very practical applications that result. I’ve not seen this approach used in the fight but I think it should be. Putting a book or article titled something like “Evolution: How It Saves and Enhances Our Lives” in the hands of pro-science school board members and their supporters in “citizens for science” groups would, I think, help. Knowledge has practical applications that speak louder to most people than the does “the beauty of it all”.

  6. In research, anytime you transfect a cell line(or transform bacteria) and positively select for them…thats evolution! That happens countless times in research too.

  7. He uses terms like “evolutionary analyses”, but he just mean genetics? Does any of this depend on any Darwinian principle or on what some people call macro-evolution?

  8. In response to Roger (#8):

    By “evolutionary analyses”, I certainly do not mean “just genetics.” Obviously, the field of genetics has incorporated a great number of evolutionary principles in recent decades, so many genetic analyses do indeed depend on evolutionary principles. However, I was specifically referring to the methods related directly to those evolutionary principles and that have been developed explicitly to study evolution (such as detection of selection and phylogenetic analyses). These methods were developed by evolutionary biologists, using evolutionary principles, to study evolution, and they are now critical to the study of human health (as well as many other disciplines).

    The applications are not just from studies of short-term evolution, either. Comparative studies across species separated by many millions of years are critical for understanding the functional nature of genes and how these genes interact with pathogens and how changes in the genes produce health-related problems. The last example that I gave was one such study. In addition, investigations of deep phylogeny are now the primary method we have for identifying emerging diseases. Furthermore, what would be the value of the comparative genome projects without evolutionary analyses to guide the analyses of the genes and the changes that have occurred among the species?

  9. David, could you give a link to some example of a medical use an evolutionary analysis that creationists would reject? I am not a creationist, and I am not sure exactly what they reject, but my impression is that they accept most of genetics and maybe even most of the principles used in the above papers. To really demonstrate the value is evolutionary biology in medicine, it would be nice to have an example that is contrary to creationism.

  10. In response to Roger (post #10):

    Different creationists reject different aspects of science, and seem to present a moving target for what parts of science they reject. But a common target of many creationists (for example, the creationists on the Texas State Board of Education) is the common ancestry of life. Several of the examples that I presented in the last two posts involve deep phylogeny and the common ancestry of life (for example, the sodium channel example, the identification of emerging diseases using the tree of life, the evolutionary comparison of genomes in the genome projects). Phylogenetic analyses on the relationships across life have become one of the most important methodologies that evolutionary biology has contributed to biomedicine. Last year (2008) alone, there were over 10,000 research papers that included the words “phylogeny” or “phylogenetic” in the title or abstract, and many more papers that used phylogenetic methods. Where are most of these papers? Most are in the biomedical literature, and many of those rely on comparisons across species that would be rejected by creationists.

    If creationists accept the common ancestry of life, and accept the role of natural mechanisms such as natural selection and genetic drift to account for the evolution that we observe across life, then I would not call them creationists. At that point they are theistic evolutionists.

    In truth, of course, no amount of scientific evidence will convince the creationists. If it could, they would have been convinced long ago, because the evidence in support of the evolution of life is overwhelming, and there is zero scientific evidence in support of creationism. Rather, creationists believe what they believe because of faith in ancient writings that they hold sacred, and all the evidence in the world has not and will not change their minds. They simply reject science in favor of their religious perspective, and reject all scientific evidence that conflicts with their views. It is certainly their individual right to do so, as long as they don’t promote their religious viewpoints in public school science classes or pretend that their views are scientific.

  11. A follow-up to my last post (#11):

    I just listened to an NPR show about the Texas School Board hearings at http://www.onthemedia.org/

    In that segment, a representative of the Discovery Institute said that the three big areas of evolutionary science that they want to challenge in Texas public schools are “natural selection, mutation, and common ancestry”.

    Therefore, I would say that all of the examples I gave in the original post are extremely relevant to this issue. They ALL use principles of natural selection, mutation, and common ancestry to inform us about matters of human health.

    I think this frames the debate quite nicely. The so-called “weaknesses of evolution” that groups like the DI are pushing concern basic, fundamental facts of evolutionary biology: things like natural selection, mutation, and the common ancestry of life. There is certainly no scientific debate about the overwhelming evidence that supports each of these three fundamental principles, but the DI and other pro-creationist groups want our children to be taught otherwise in science classrooms.

  12. David,

    I think a good suggestion is to buy every Texas schoolchild a copy of my book . .

  13. David, I am not just asking for papers that mention phylogeny or that include comparative studies across species. Can you give me a link to a paper with practical value in medicine that uses some aspect of evolutionary biology that the Discovery Institute would reject? You have papers that use concepts like mutation, but not principles that the Discovery Institute or creationists would reject, as far as I know.

  14. Response to Roger (#14):

    As I noted, in Texas the DI is trying to cast doubt on basic evolutionary facts that are not in dispute within scientific circles (they listed “natural selection, mutation, and common ancestry” in the NPR piece I referenced in post #12). Clearly, ALL of the examples I have already given provide “practical value in medicine that use some aspect of evolutionary biology that the Discovery Institute would reject”, since the DI states that they doubt natural selection, mutation, and common ancestry. I know it is amazing…they reject the basic facts of evolution that are supported by hundreds of thousands of published studies and abundant and indisputable scientific evidence.

  15. The DI guy did not reject natural selection, mutation, and common ancestry. He merely endorsed encouraging Texas students to “analyze, evaluate, and critique some of the core evolutionary concepts like natural selection, mutation, and common ancestry.” I am still waiting for an example.

  16. Who cares what creationists reject. They are rarely ever specific any longer since every time they are, they get blown away by evidence, just like they did for each claim of irreducible complexity.

    Roger, I do not understand your triple request for an example that creationists would reject. Let them do the work for a change and give their example so that Drs Hillis or Coyne or others can then refute.

    Dr Coyne, I disagree that every someone should “buy every Texas schoolchild a copy of my book”. I think someone should buy every Texan a copy of your book (and Neil Shubin’s too) 🙂

  17. The DI guy did not reject natural selection, mutation, and common ancestry. He merely endorsed encouraging Texas students to “analyze, evaluate, and critique some of the core evolutionary concepts like natural selection, mutation, and common ancestry.” I am still waiting for an example.

    I don’t care about the creationists. I am just trying to get an answer to Coyne’s question.

  18. As a person deeply interested in all science, and as one devoted to the scientific method — though I’m *not* a scientist at all — I found this article greatly interesting and was impressed with Dave’s original e-mail and his responses here.

    On the other hand, as a native Texan (albeit it one living far abroad), I am ashamed this is such an issue in my state. I wrote the State Board of Education before the language was approved objecting to it. Once the language was passed as it was, granted somewhat watered down from what the chairman would have liked (and he’s a medical professional!), I wrote again, partly gloating directly to the chairman that his fondest dream had partially failed, partly bemoaning the fact that such an idiotic stance got a hearing in the first place, much less partial passage.

    As a university educator, if not one of science, I am deeply concerned about this.

    I have relatives who buy this bunk, including a university-educated nurse. She’s as sweet as sweet can be, and will sit there and tell you how the apparent differences in the ages of, say, fossilized dinosaur remains and human remains are “just some more of God’s wonderful mysteries.” I just inwardly sigh, lacking the heart to go on the intellectual attack of the dear (to me, anyway) woman.

    The fact that she is educated is relevant. Given her acceptance of creationism, is it any wonder that some people less educated also accept it? Her argument re: God’s mysteries is unanswerable.

    I read an interview article in one of the major weekly magazines not long ago with three different people regarding varying viewpoints on this subject. One made the telling (if obvious) point that when faith and science collide, faith often wins out. The very existence of the creationists’ arguments ends all doubt of the truth of that assertion.

    Thanks for the article — and thank you, Dave, for letting your original e-mail be published.

  19. Devil’s advocate here:
    Coyne writes, “I have sometimes written that evolutionary biology doesn’t have much practical value in medicine or other areas impinging on humanity’s material well being.”

    I appreciate that you never said “NO practical value.” Given the vastness of the field of medicine, isn’t a few hundred to a few thousand counterexamples to Skell’s thesis still amount to “not much practical value”?

    Semantics, I realize.

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