On the origin of species—again
by Lauren J. Bryant | © Washington State University
Everyone calls them genius awards, except the foundation that gives them. When describing recipients of its annual $500,000 grants, the MacArthur Foundation avoids "genius"-rather, says the Foundation, MacArthur Fellows are people who transcend boundaries, take risks, and synthesize disparate ideas and approaches. That's a dead-on definition of Loren Rieseberg ('87 Ph.D. Botany), an evolutionary biologist at Indiana University Bloomington who received a MacArthur Fellowship in October 2003.
When Rieseberg arrived at Washington State University in 1984 to pursue his doctorate, he was a model student, energetic and eager, recalls his advisor and former WSU professor, Douglas Soltis, now at University of Florida. Soltis handed him Verne Grant's 1981 classic, Plant Speciation, and told him to find a doctoral project.
"I discovered then that I wanted to spend my life studying the origin and evolution of plant species," Rieseberg says.
Despite Charles Darwin's On the Origin of Species, exactly how new species originate has remained unclear for nearly 150 years. Rieseberg decided to take a new look at the old question by focusing on hybrids-the crossing of two species. It was a controversial choice.
Gardeners and farmers favor hybrids-hardy flowers and sturdy crops that resist disease. But natural hybrids are often sterile, unfit, and unable to reproduce. From the biological perspective, then, hybrids were largely considered an evolutionary dead-end.
That didn't stop Rieseberg. Using high-tech tools of genetic analysis-quite new in the 1980s when he started his work-Rieseberg has studied hybridization in sunflowers, making a string of discoveries that have revolutionized scientists' understanding of how evolution works. In a landmark 1996 study, he recreated the birth of a new species by crossing sunflowers in the lab, proving that hybridization is, in fact, an important tool of evolution.
What's more, he came up with the same sunflower species three different times, demonstrating that evolution, commonly thought to be random, can be repeatable. More recently, he's shown that hybridization is a major force in sunflowers' adaptation as well.
Rieseberg is a hybrid himself: a native of British Columbia who lives in the Midwest, a former Seventh-Day Adventist turned evolutionist, a scientist who sculpts, a soft-spoken wannabe schoolteacher whose MacArthur has garnered international attention, including an invitation to lecture on evolution for the ruling family of the United Arab Emirates.
Bringing the unexpected together is Rieseberg's genius. Jeffrey Palmer, distinguished professor of biology at IU, calls Rieseberg's ability to integrate distinct experimental approaches "unsurpassed." His creative blending has led to "very convincing and elegant" confirmation of hybridization as an evolutionary process, says Edward Schilling, head of the botany department at University of Tennessee and Rieseberg's master's advisor. Eva Sanders Allen, a doctoral graduate from Rieseberg's lab who continues to work with him at IU, says she's called him genius many times: "He remembers everything, grasps everything, sees where the holes are, and knows what new technologies can make possible."
And old technologies, too. Rieseberg has a tradition of "stoning" his graduating doctoral students- giving them a gift of a sculpture made from Indiana limestone. A few years ago, he couldn't find a sculpture he liked for a student who was leaving in just two days, so he decided to make one. He carved it with a screwdriver.
Since then, his creations have gotten more elaborate. Rieseberg wants to sculpt a near life-size buffalo for his front yard. The buffalo has become a sort of totem for him-he considers the animal a "primary dispersal agent" for the sunflower species so important to his work.
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