Notes from the field: How a molecular geneticist got wet

When I was growing up in Southern California, I wanted to be many things, including a doctor, a lawyer, a veterinarian, and the first woman president. But the thing I loved the most was the ocean, and I spent as much time as possible at the beach, swimming in the waves, combing for shells, and exploring the tide pools. So I have always had this lurking desire to become a marine biologist, live on a boat, and follow dolphins around. But when I went to college, I had decided that I was going to be an orthopedic surgeon and duly embarked on my pre-med courses and ended up with a major in Molecular and Cellular Biology with an emphasis on Genetics. But those lurking desires to be a marine biologist kept popping up and I spent the summer after my junior year at the Duke Marine Lab in Beaufort, North Carolina. This was my first real exposure to science and scientists and I loved it. Any ideas about orthopedic surgery were gone, and I wanted to be a scientist. I particularly loved living at the marine lab, where I got to spend all day doing molecular biology and all my free time swimming and exploring in the ocean. But when it came time to apply to PhD programs that fall, I decided that although I loved marine biology, molecular biology and genetics were the tools that I needed to study biological problems. I thought that someday I could use those tools to explore marine biology. So I never did submit my application to the University of Hawaii and instead went to Princeton University. There, I joined Tom Vogt’s lab and received excellent training in mouse developmental genetics. But sometimes during those long days in the lab when nothing was working and it seemed like grad school would never end, I would think about how I really wanted to be a field biologist, where I could be outside working with “real” organisms. However, when I finished my PhD, I somehow forgot about that lurking desire to do fieldwork and marine biology. I decided to stay within the world of developmental genetics, but fortunately was accepted as a post-doc in David Kingsley’s lab at Stanford University. David is also a mouse geneticist, but it was clear that he had broad interests in evolution, particularly in the amazing diversity of skeletal morphologies present in vertebrates. So David and I started to ask the question: “What kinds of genetic and molecular changes actually contribute to morphological variation in natural populations?”. In order to address this question, we wanted to find a vertebrate organism that had lots of phenotypic variation (particularly skeletal), but we needed to be able to cross these variable populations in order to take a genetic approach to identify the genes underlying this variation. To find our ideal organism, we spent one of the most fun summers of my career in science: we went to the library and read about all sorts of crazy systems that I never knew existed and talked with many different people in diverse fields. Because we were interested in vertebrate evolution, fish were an obvious candidate group, given the dazzling array of phenotypic diversity and the relative ease of raising large numbers of fish in the lab. It was as I was walking across the Stanford campus with an armful of books on fish that I realized that my lurking desire was actually being fulfilled: I was going to use molecular biology and genetics to study marine biology! When David came across a chapter by Mike Bell about threespine sticklebacks in a book called The Evolutionary Genetics of Fish, he immediately gave it to me to read. We both knew we had found our ideal organism (Fig. 1). The threespine stickleback has evolved a huge diversity of morphologies and behaviors in the last 10,000 years since the glaciers melted. However, there was some work to suggest that you