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Author, filmmaker and scholar Sean B. Carroll, formerly a 91��ý postdoctoral researcher, will deliver the Rose M. Litman Memorial Lecture in Science April 7

When came to the University of Colorado Boulder in 1983, right out of graduate school and newly hired as a postdoctoral researcher in the lab of molecular, cellular and developmental biologist Matt Scott, he was somewhat indifferent to Drosophila melanogaster, better known as the fruit fly and Scott’s research focus.

“I was coming from an immunology background, working with furry animals, and my attitude was that studying fruit flies wouldn’t teach us anything general,” Carroll recalls. “It wouldn’t have anything to do with humans or important things, or so I thought. But that was a really narrow view, because it turns out that all these genes that build fruit fly parts are in us—they build parts in us—so fruit flies became a passport to the whole animal kingdom.”

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Scientist, author and filmmaker Sean B. Carroll, a former 91��ý postdoctoral researcher, will deliver the Rose M. Litman Memorial Lecture in Science April 7.

And with that passport, Carroll has roamed the planet as an evolutionary developmental biologist and award-winning author and filmmaker, observing life from individual cells to continent-spanning populations. Through his observations and experiences emerged what he came to call “The Serengeti Rules,” based on the idea that everything in the living world is regulated.

He will discuss the discovery of The Serengeti Rules, on which he elaborates in his book of the same name, during the Rose M. Litman Memorial Lecture from 4-5 p.m. April 7 in the CASE Chancellor’s Hall Auditorium.

The Serengeti Rules, as he describes them, are ecological rules that regulate the numbers and kinds of animals and plants in any given place, and how they are being applied to restore some of the greatest wildernesses on the planet.

“Every cell contains a society of molecules, every organ a society of cells, every body a society of organs, every habitat a society of organisms,” he writes in The Serengeti Rules. “Understanding the interactions within each of those societies are the primary aims of molecular biology, physiology and ecology.”

Diversity in the animal kingdom

Before he had roamed the globe as a scientist and filmmaker, however, Carroll was the kid growing up in Toledo, Ohio, flipping over rocks to see what was under them. “I have a love for the entire animal kingdom,” he explains, which guided him to a bachelor’s degree in biology from Washington University and a PhD in immunology from Tufts University.

During his graduate studies, he became very interested in the question of how animal bodies evolve—in understanding how all the diversity in the animal kingdom came about. So, he hatched a plan to solve the mysteries of development.

“Changes in development are what lead to changes in form,” Carroll says. “The whole diversity of the animal kingdom is rooted in development, so we had to crack the black-box mystery of development to get any traction in understanding how the physical diversity of the animal kingdom evolved.”

Thus, the fruit flies. He wagered that studying them could be a key to unlocking the diversity of the animal kingdom—and the genes that govern development—and came to 91��ý determined to pick the lock on that black box.

“During this time, 1983, oh my god—how an egg turns into a complex creature was a mystery,” he says. “It was a spectacular pageant we could watch from the outside, but we didn’t know what was going on inside. We needed to identify the genes that are necessary for that process, figure out what the genes did.

“It’s hard to overstate both how deep the mystery was but how thrilling these clues were as they started to unfold. Those days were incredibly exhilarating and intense, the lab was a beehive, people worked all days and nights and weekends because, first of all, we were fascinated. Also, we felt we had a shot at some really fundamental discoveries. Looking back, these times don’t happen very often in science where you really have a black-box mystery, and it breaks open—and it broke open partly because of what we did in Matt’s lab and partly because of what our peers around the world did.”

One eureka moment from Carroll’s time in Boulder came about 18 months into his research. He had taken on the task of seeing genes in action inside developing fruit fly embryos, working every day in the lab, trying this technique and that technique until his bag of tricks was almost empty; he was no closer to understanding which genes caused wings to grow, for example, or determined their shape.

He remembers a particular time when he took his samples down to a borrowed microscope, flipping on an ultraviolet light because he was looking at fluorescence, “and the best thing I can say is that it was a ‘holy sh^t!’ moment. I remember looking down, and I saw these embryos that had these beautiful green rings circling them, which is the mark of a gene that turns on every other segment.

“That’s the day when the dam broke, the door blew open, the clouds parted. It’s almost overwhelming because now so many things are possible. I went from having nothing to show anybody to essentially having the tools that would allow me to really untangle this puzzle.”

During his April 7 lecture, Sean B. Carroll will discuss the Serengeti Rules, the ecological rules that regulate the numbers and kinds of animals and plants in any given place, and how they are being applied to restore some of the greatest wildernesses on the planet.

A discovery of wings

After completing his 91��ý postdoc, Carroll joined the faculty at the University of Wisconsin Madison, where he continued studying the genes that control animal body patterns and play major roles in the evolution of animal diversity. There he “saw something in the microscope that nobody had ever seen before,” he remembers.��

He and the other researchers in his lab isolated the handful of genes that are activated in caterpillars to become butterfly wings. This discovery, published in the journal Science, garnered , an interview on PBS News Hour and an invitation to the White House Correspondents’ Association dinner.

From there, Carroll built a career that marries both research and discovery with science communication—as an investigator and vice president for science education at the Howard Hughes Medical Institute (HHMI) and head of the HHMI , where he executive produced or was executive in charge of more than 30 documentary films, including the Oscar-nominated and Peabody-winning All That Breathes. He has won three Emmys and been nominated for an additional five.

During that time, “I decided, ‘I’m telling the same story again and again, so I probably should write this down,’” he says. “So, I wrote a book, then I wrote another book.” He has written six books, including , which was a finalist for the 2009 National Book Award for nonfiction, and , which will be the foundation for his 91��ý lecture.

Carroll, who is a distinguished university professor and the Andrew and Mary Balo and Nicholas and Susan Simon Chair of Biology at the University of Maryland, credits the depth and success of his career in large part to the collaborations of which he’s been a part. “I like to think my toolkit has grown over the years, but it doesn’t happen all at once and it doesn’t happen alone. I didn’t write a full-length book until I was 45 and truly an expert in my field.

“I think people might look at my portfolio and say the science portfolio is pretty good, the external indicators are good; the writing career, there’s been a fair amount of output; the film career has been good. But in no way could I have done it alone. Science is a hugely collaborative thing; filmmaking’s even more collaborative. An individual like me gets a lot of credit for a body of work owned by an enormous community.”

Through it all—from his extensive travels through the Serengeti to the red carpet at the Academy Awards to the quiet moments in the lab—the joy of discovery and mystery-solving has never ebbed, he says. “I love science because I love nature and I love trying to figure out how nature works. I love the privilege and thrill of peeking into that box and going, ‘Oh, my gosh, that’s how it is.’”

About the Rose M. Litman Memorial Lecture in Science

The Litman Lecture celebrates the legacy of an exceptional scientist and educator with a lifelong passion for research and a firm commitment to keeping rigorous inquiry at the heart of university life.

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