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Transcript of the Interview with Dr. Joe Thornton on Evolutionary Biology

October 17, 2008

Introduction: This Findings podcast is brought to you by the National Institute of General Medical Sciences, part of the National Institutes of Health. The Findings podcast series features the NIGMS-funded scientists profiled in each issue of the Findings magazine.

Carlson: Hi, I'm Emily Carlson, and I'm here with Joe Thornton, an evolutionary biologist at the University of Oregon. Like a historian or anthropologist, Dr. Thornton looks deep into our past to better understand who we are today. He has resurrected a 450 million-year old protein to explore how a specific group of hormones and their receptors evolved. This information could help us understand the origins of hundreds of diseases and find new ways to treat or prevent them. Dr. Thornton, what are the major challenges to understanding evolution from a scientific standpoint?

Thornton: I think we're in a very exciting time right now where we are just beginning to understand how specific mutations produced new phenotypes and new biological systems, new cellular systems, new molecular systems, new developmental processes of the body. The ability to get mechanistic about these things means that we can not only understand precisely how specific biological features of interest evolved, but we can also get new insight into age-old questions about the evolutionary process.

Carlson: Why are you interested in the hormone receptors?

Thornton: Our goal is to understand how the diversity of hormones and receptors in our body evolved, how their specific interactions with each other evolved. It's the first step toward understanding even more complex systems made up of many more parts. This question of how do interactions between different molecules evolve is a central but really underappreciated question. Virtually everything that a living cell does is regulated or driven by specific interactions between molecules. We know very little about how proteins and other molecules have evolved their specific interactions with each other.

Carlson: Why is it important to know that, about the evolution of the proteins and the receptors?

Thornton: We have these amazing bodies that do incredibly complex, efficient things. Knowing how the processes that drive our bodies evolved and understanding their origins, where they came from, seems to me essential to understanding who we really are and how we fit into the world. So it's very similar to the importance of understanding history for understanding our current political situation or the state of society. So what we're trying to do is apply that sort of approach to the molecular systems that run our bodies.

Carlson: How are you going about doing that?

Thornton: So the program in our lab is to use phylogenetic techniques to reconstruct the history of the gene family of steroid hormone receptors, to understand exactly when the genes originated and how their sequences have changed over time, and then to use molecular biology to test specific hypotheses about what the functions of ancient receptors were in order to understand which functions are ancient and which ones are derived, and also to use manipulative experimental techniques to understand how the specific mutations that occurred during evolution changed the function of the protein as they evolved.

Carlson: Are you essentially creating evolution in the lab?

Thornton: We're recapitulating the historical process of evolution. This is more like archeology, going back to reconstruct the forms that were here on Earth a very long time ago and then recapitulating the changes in genes that occurred hundreds of millions of years ago. So we're not making a new evolutionary process happen. We're recreating the process of evolution as it happened in the deep past based on the traces that exist in our gene sequences today.

Carlson: You were an English major. How do you think majoring in English and studying literature and focusing on your writing has helped you become a better scientist?

Thornton: It helped in a couple of ways. One of the most important aspects of doing science well is being able to communicate your findings and their importance to others. So a beautiful experiment that you can't explain, that you can't make other people appreciate and understand the importance of, is not a significant contribution to science. It's the whole package: asking the right questions, developing experiments that can answer them, carrying out those experiments, and then communicating them to people. I think that having studied literature and spent so much time writing has helped me with that. The other reason is a little bit more abstract. I see science as a way of contributing to culture, as a way of understanding ourselves, the world around us, and how we fit into that world, what the meaning of our biology is and how an understanding of the natural world affects our sense of ourselves and our place here on Earth.

Carlson: So on your CV you allude to getting your degree a long time after you actually attended?

Thornton: I was very hungry for some contact with reality after all this time studying literary theory behind the ivy walls of Yale. So I decided to leave school just short of getting my bachelor's degree and I wanted to do political work on the environment because that was the issue I was concerned about. So I started to work with Greenpeace on their toxics campaign. I had an incredible experience learning about those environmental issues and I also learned a lot about the political system, how decisions about industry and the environment and regulation are made. I became a specialist in helping communities understand what was in the scientific literature and also analyzing the science for its implications about what we ought to do about pollution and when it came time for me to move on in my career and do something else, I was so fascinated with the science that I wanted to pursue the science directly, rather than indirectly. So that's why I went back to school in biology. At the time, the big issues that I had been working on in environmental health were endocrine disruption, so the effects of these chemicals on our hormone receptors and our hormones. So I wanted to understand how those systems evolved. So there is a direct connection between my research program now and that history of environmental activism.

Carlson: What kinds of reactions do you get from your kids when you tell them what you're working on? Do they sort of have that feeling of "that's so awesome, Dad"?

Thornton: Yeah, they think it's pretty cool. They also like coming in and seeing the weird creatures when we have creatures that are alive today. I think that exposure to what I'm doing gives them an appreciation for how old life on Earth is and the incredibly long process that evolution has taken to give us the biology that we have today, and that's not an obvious thing that all kids are going to understand before they study it.

Carlson: I know that talking to you has certainly helped me grasp just how old our biology is. Thanks, Dr. Thornton.

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