Monthly Archives: January 2014

Why we have Four Limbs

This article contains a possible, evolutionary answer as to why all animals with a backbone and jaw develop with four limbs (based on the scholarly publication published by Laura Nuno de la Rosa). The hypothesis is that limbs develop in areas where the layers of tissue (during early development) are separated enough for an appendage to form-it just so happens that the location of the separations and their favorable interactions with other tissues allow those limbs to form. What struck me the most about the article was not its content but instead a line that reads,  “As with any long-standing question in evolutionary biology, numerous ideas have been proposed to explain different aspects of the origin of paired appendages in vertebrates” (Science Daily). This reminded me of our discussion in class about the importance of thinking through all possible hypotheses to these evolutionary or distal questions. Also noteworthy is a line in the article that reads, “…the focus of the hypothesis on global embryonic patterning and tissue interactions emphasizes the importance of accounting for factors other than genes (epigenetics) to understand development and evolution” (Science Daily). With that, the author emphasizes the importance of viewing evolutionary issues at a macroscopic level instead of only focusing on the microscopic, DNA level. That is certainly another interesting idea to keep in mind when considering our upcoming assignment…Here’s the link to the article. At the end of the text, there is a citation of the the scholarly publication the article is based on as well.

Evolution Under Pressure

(from article - see link)
(from Wired Science)

Interestingly enough, this article entitled, Does Evolution Evolve Under Pressure?, in Wired Science magazine discusses a slight departure in the topics discussed Tuesday in class regarding understanding the concept of evolution and natural selection.  According to the article, Susan Rosenberg theorized that bacteria can self- mutate in the sense that they can, under pressure, induce increased rates of mutations in the hopes of finding an “escape route”.  This sort of theory straddles the lines between Darwinian and Lamarckian realms of thought: the grey area between self-mutation and trial and error. Some may argue that this is a form of artificial selection because the general course of evolution is not occurring – it is being tampered with by the organism itself. This then also begs the question that if this theory holds to be true, then what does this indicate for certain realms of study such as antibiotic resistance and the evolution of cancer? If scientists or researchers could somehow try to control for stressors that induce mutations in the first place, could that somehow impede the process of evolving antibiotic resistance and further change the practice of medicine and oncology? Ideally, if this theory holds to be true and applicable, evolution could not only be important to understand in medical education as an important framework and understanding why, but now could have direct implications to preventative medicine in terms of determining how. Doctors could advise against certain stressors that induce certain mutations in some bacterial infections or certain tumors (that can also develop antibiotic resistance).  The article also goes into further detail describing studies that were able to create conditions that induce organisms to mutate at higher frequencies. This theory largely remains controversial, and it would be interesting to look into how critics explain a reasoning behind the successes of these mentioned experiments. A link is provided to the article below:


C. difficileMove over evolutionary medicine and make room for evolutionary veterinary medicine. Actually, it seems vets have had a handle on using evolutionary reasoning for quite some time. For example, fecal transplants to restore micobiome health after C. diff infection is an established technique for cattle! Perhaps this explains why my terrier looks at week old dog poop on the sidewalk like he just found buried treasure. The website has loads of great resources and articles:



There are more courses in evolutionary medicine now than ever. Here is a link to a list of undergraduate and graduate course syllabi on the topic. Our course syllabus in posted on blackboard. How does it stack up? What topics from similar courses would you like to see covered? In general, this is also a great resource for finding presentation topics and ‘poaching’ papers to post and discuss on our blog.


Welcome to the course blog for biol285: Evolutionary Medicine. This is a space for students and others to discuss topics relating to the interface of evolutionary biology, human health, and disease.

Course details, including the syllabus and required for class discussions will be posted on blackboard.