Main Menu
Welcome
I had the priviledge to meet Randolph Nesse ("Why we get sick", his blog) here in Berlin at a dinner with visiting blogger Bora. He now sent me one of his articles on Evolutionary Medicine: "The great opportunity: Evolutionary applications to medicine and public health" It's open access so you can go and download it without subscription. What is evolutionary medicine? From the article: "At the core of evolutionary medicine is recognition that diseases need both proximate explanations of bodily mechanisms and evolutionary explanations of why natural selection has left the body vulnerable to disease." The article is about how much medical research and education would have to gain from a more evolutionary perspective in their approach to disease. Here are some more quotes from the text:An evolutionary perspective fundamentally challenges the prevalent but fundamentally incorrect metaphor of the body as a machine designed by an engineer. Bodies are vulnerable to disease – and remarkably resilient – precisely because they are not machines built from a plan. They are, instead, bundles of compromises shaped by natural selection in small increments to maximize reproduction, not health. Understanding the body as a product of natural selection, not design, offers new research questions and a framework for making medical education more coherent.
I also liked this one:Universities talk a lot about promoting interdisciplinary work precisely because their structures so efficiently prevent it. However, disciplines exist for good reasons. There is too much to know. Trying to synthesize work from diverse areas is frustrating, especially if the goal is general understanding, not some fine point. Also, going beyond your specialty means you will inevitably get some things wrong. It is easier to maintain quality by keeping to a narrow focus.
The authors argue, and I think successfully, that without the evolutionary perspective, medicine is only using half of biology. Obviously, one important aspect is genetics. The authors reinforce the notion that many if not most genes which are associated with a certain disease are not defective in any way:Many physicians think of genes that cause disease as abnormalities in an otherwise ‘normal’ genome. This is a nonevolutionary view on two counts. First, it tacitly views the genome as a product of design with a blueprint that defines ‘normal.’ The genome is, instead, a collection of those genes that have tended to increase reproductive success (or hitchhiked on the success of other genes) while interacting with each other and the environment to construct a functional organism. Second, while some DNA sequences can be accurately described as ‘damaged’, it is increasingly clear that many medically relevant genetic variations are helpful or harmful only in interaction with particular aspects of environments.
I really like this argument and I also think that it constitutes a very profound insight which changes the way in which diseases are perceived. There is one really small instance where I would argue differently, though:Taking out [...] a gene and looking to see what goes wrong can generate hypotheses about how an organ or gene is useful. Often, no abnormality is observed. Of course, this does not mean that the gene is useless, only that its effects are covered by redundant systems, that its benefits are manifest only in special situations, or that the benefit is just too small to be observed in a laboratory setting.
Redundancy is something that is very hard to achieve in evolution. If one gene is functional, the redundant gene is not needed and will accumulate mutations. I would argue that degeneracy is a much better explanation for many failures to find a phenotype associated with a specific gene knock-out.Besides the interesting and important insights into evolutionary medicine in general, the article also offers a few fascinating factoids such as:
Nearly 10% of Staphylococcus aureus are now resistant even to methicillin; infections
caused by this resistant organism now cause 18 650 deaths per year, more than the 12 500 caused by AIDS (Klevens et al. 2007). The economic burden of antibiotic resistance is estimated at about $80 billion annually in the USA.
caused by this resistant organism now cause 18 650 deaths per year, more than the 12 500 caused by AIDS (Klevens et al. 2007). The economic burden of antibiotic resistance is estimated at about $80 billion annually in the USA.
In all, I found it to be a very interesting and enlightening article which will help me explain why what I'm doing is not only fun, interesting and beautiful, but may also one day be useful.
Posted on Wednesday 04 June 2008 - 11:14:27 comment: 0
{TAGS}
{TAGS}
Render time: 0.0968 sec, 0.0100 of that for queries.