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13 Life with Sea Urchins

Rudolf A. Raff Indiana University Press ePub

My former postdoctoral advisor, Paul Gross, liked to say that “your graduate students are your friends, but your postdocs are your enemies.” This was because graduate students would go off to do postdoctoral work in new areas of research but departing postdocs would want to kick-start their independent careers by continuing the research they had developed during their postdoctoral years. Thus they were virtually destined to become competitors with their own former mentors. Nonetheless, Paul was generous about allowing postdocs to take their projects with them. For several years at Indiana, I continued the study of how protein synthesis was stimulated at fertilization of sea urchin eggs. By 1978, we had published our main findings on the “masking” of mRNAs of eggs and on the regulation of protein synthesis from these mRNAs in embryos following fertilization, and I began to get restless. I was ready to start a new direction of research. I thought it was time to return to my early interest in evolution, but now with a better understanding and better methods, and a view toward thinking about evolution and development. Developmental and evolutionary biologists had diverged in their research objectives to the point where neither thought much about the role of the other. My first approach to the experimental study of the evolution of development would be based in Indiana but was boosted by priceless summers in Woods Hole, Massachusetts, where I learned about marine embryos as creatures with life histories and their own evolutionary careers. Those evolving larvae have occupied my scientific life for three decades.

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11 Evolution as Science

Rudolf A. Raff Indiana University Press ePub

When I was a kid and enjoyed collecting fossils and fantasizing about live dinosaurs, I was completely, even magnificently, ignorant when it came to grasping what evolution is, beyond a vague notion of one kind of dinosaur following another through time to their inevitable doom. There were many things I didn’t even know that I didn’t know – like what science itself is. Then there were other gaps in my knowledge, most critically of the historical origins of evolutionary biology and, most difficult to grasp, what the living science of evolution is all about. Much education happens by accident and curiosity. I have never had a formal course in evolution, and my becoming an evolutionary biologist came as a result of my reading as I became a molecular developmental biologist. I only later came to do research on the relationship between developmental biology and evolution. Now, as a whim of fate, I teach evolution to students who have no idea that I never took the course myself.

Science is about understanding the natural world. As scientists, we assume that nature operates under the actions of consistent natural forces; no miracles or other supernatural phenomena are involved. This is not to suggest that scientific reality will necessarily correspond to commonsense reality. The bizarre world of quantum mechanics makes no connection with common sense, nor can we have personal comprehension of the vast geological times we have to think about in studying evolution. Scientists assume that we can extract a consistent understanding of the natural world, and that we can test our working models, hypotheses, under tough criteria. Hypotheses should seek the least convoluted assumptions; they should not require special fudge factors; they should explain existing knowledge; and finally, they must predict the results of experimental test or new observations. Only hypotheses with a high degree of explanatory power and a history of surviving all challenges are promoted to the status of a theory. But science is always conditional. Even theories may be susceptible to being overthrown if a better model of the world becomes available. Some theories, like the rule that matter is composed of atoms, that the Earth revolves around the Sun, or that life has evolved, are strongly established and are unlikely to be incorrect.

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6 Transformations

Rudolf A. Raff Indiana University Press ePub

After one more family move, I did my last year before college in another new school, Gateway Senior High in the Pittsburgh suburb of Monroeville. As many of my classmates were also new students who had just transferred there with the metastasis of suburban sprawl, no cliques of cool kids had built up and the teachers were good. Perhaps the best was our exceedingly sarcastic English teacher, who supplied just the right attitude for reading about the oddities of the Macbeth family and Julius Caesar’s unfortunate misjudgment of his friends. Two of my Gateway friends eventually took doctoral degrees in science. Tom Taylor became a mechanical engineer, and Mary Boesman became an immunologist. She died in 2007. Mary and I both read history and lent each other books. This was the best of my twelve-year run of schools, and I remember it fondly.

But that pleasant year also included the looming matter of where I should go to college. Given what my family could afford, my choices were limited. I could attend a university in Pittsburgh and live at home or attend the state university and live away. Not much of a contest. Despite the good universities around Pittsburgh, living at home would suffocate my becoming independent. After all the adventures of filling in applications, taking College Board exams, being interviewed, and sitting in on a sprinkle of college class lectures, I left for Pennsylvania State University in the fall of 1959. My parents took me to State College and helped me move into my first dorm, but I was anxious for them to leave. I now had to make my own triumphs and my own missteps (ludicrous missteps outnumbered triumphs that first year). Our first assembly as freshman students included an address by the president of Penn State. He told us to look at the person on our left and the person on the right. One of them would be gone before the year’s end. Perhaps that encouraging invitation to embarrassed sidelong glances constituted what might be described as a subtle preparation for life.

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15 Evolution in the Tasman Sea

Rudolf A. Raff Indiana University Press ePub

In the early 1980s, I started earnestly hunting for the right organism as an experimental system for delving into evo-devo. I thought the ideal animal would be one in which the evolution of early embryonic and larval development could be readily studied because embryos and larvae are crucial stages in development and are simple in cell numbers and types compared to adults. My first efforts were made using the familiar sea urchins of the Northern Hemisphere. I found that we could explore evo-devo at the gene level in sea urchins and published our first evo-devo paper in 1984. In it we showed that a major innovation in the expression of histone genes in sea urchin eggs had taken place with the origins of advanced sea urchins in the Mesozoic, while brontosaurs munched their way across the landscape. We could thus correlate a unique gene regulatory mechanism with a set of macroevolutionary events in sea urchin evolution. But the events were too distant in the past to help unravel ongoing developmental evolution. So I’d have to look farther afield.

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2 Layers of the Past

Rudolf A. Raff Indiana University Press ePub

My mother, Therese Dufresne, was the daughter of a well-liked local physician, Albert Dufresne, who practiced from 1930 onward in Shawinigan and the surrounding countryside. His house calls could mean anything, including grueling trips into the backcountry by horse-drawn sled or canoe. By the time he retired, my grandfather had delivered or treated most of the living citizens of the town. He once estimated that he had delivered eight thousand Shawinigan babies. In 1966 he was made a Commandeur de l’Ordre de Saint-Gregoire-le-Grand, a papal award for his charitable acts to his many patients unable to pay in hard times. A street in Shawinigan now bears his name.

Going to visit Shawinigan during summer vacations was the highlight of my early life. Shamefully, it was not because I liked spending an entire vacation in my grandparents’ rather formal house. I was too energetic for that. What I cherished most was any time I could spend out in the woods at a lake. My Uncle Gérard Dufresne’s family had a remote cottage on Lac des Îlles, where on one visit I was impressed to see the hole where an enterprising bear had clawed its way through a soil-filled double-log wall into the icehouse. What a frisson to realize that wooden doors would be as paper to hungry bears (not that they bothered cottages with people around). Most of my cottage experience though was at Lac Souris (Mouse Lake – had they run out of better names?). Here the vast Quebec forest lapped the edge of civilization. On the far side of the lake, inaccessible from the end of the rutted lake road, my uncle Guy Ricard (the husband of my mother’s sister Margot) and my grandfather had built a summer cottage. To get to the cottage from the road head, we would uncover my grandfather’s old motorboat, drag it over the wet sand into the shallows, load up supplies and gas, and push off with battered oars to get into water deep enough to lower the outboard. Then, with some boat rocking, repeated pulls of the starter cable finally got the balky engine going. We’d head off at two miles per hour in a cloud of fragrant blue smoke. If there were just the two of us, I’d be allowed to run the engine and steer with my grandfather’s nervous guidance. Once steady, I could throttle up enough to leave a discernable wake across the usually glassy surface. I have a photograph of one of those days – me a skinny ten year old wearing an oversized old raincoat of my grandfather’s belted around my waist, he with his inevitable cigar in his mouth.

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