Syracuse University Magazine

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Scott Pitnick

Evolutionary Exceptions

As an evolutionary biologist, Scott Pitnick revels in discoveries that counter conventional knowledge. For him, “cherish your exceptions” is a mantra, a guiding philosophy he brings to the lab and encourages students to embrace in research projects. “When things don’t make sense, that’s when I get excited,” says Pitnick, the inaugural Weeden Professor in the College of Arts and Sciences. “And when you observe something that’s truly exceptional to how biologists think the world should work, that’s when you should drop everything else you’re doing and invest in that.”

Pitnick, who joined the biology faculty in 1996, calls it dogma busting and he’s been at it his entire career, producing groundbreaking research in the fields of sexual selection, reproductive genetics, and speciation, with the support of more than $3 million in grants. Sperm evolution is a major focus of his research, and studies on the Drosophila species of fruit flies, along with an assortment of beetles and other insects as well as bats, have led to some intriguing findings, as well as attention from the likes of National Public Radio and The Atlantic. “Sperm are complex,” says Pitnick, co-editor of Sperm Biology: An Evolutionary Perspective (2009). “There is no typical sperm cell for the animal kingdom. They can be round, covered in spikes, have multiple tails, all kinds of forms.” 

Consider, for instance, the exceptional sexual prowess of Drosophila bifurca, which produces sperm 2.4 inches long—nearly 20 times the length of the fly itself. Pitnick discovered the unusual attribute in 1995 as a National Science Foundation postdoctoral fellow. Last year, in a comparative study published in Nature, Pitnick and his research group revealed the giant sperm was possibly the most extreme example in nature of ornamentation (think male traits used to impress females: luxurious peacock tails, massive elk antlers, striking bird colors) and that the female’s reproductive tract is designed in such a way to bias fertilization in favor of the longest sperm. “It’s clear now that the design of sperm and the female reproductive tract are co-evolving together,” he says. “Not only that, but they’re doing it lightning fast, which turns out to be important for driving the formation of new species.”

Pitnick is a restless explorer on the hunt for experiences that capture his attention, whether it’s wood carving, building a stonewall, or discovering a rare book. He has always been fascinated by animal behavior, especially insects. Growing up in Carlisle, Pennsylvania, he roamed the outdoors, collecting bugs and bones and other stuff. It led him to study entomology as an undergraduate at Cornell and earn a doctorate in evolutionary biology at Arizona State University, where he became interested in post-copulatory sexual selection. In 2010, Pitnick and biology department colleague John Belote gave the world an intimate look at fruit fly reproduction when Belote genetically engineered Drosophila melanogaster sperm whose heads were tagged with either a green or red fluorescent protein, allowing scientists to visually track them in action. The sperm are now used in more than 60 research labs worldwide. “It opened a window into basic reproductive biology that nobody had been able to see before,” he says. 

That collaboration eventually led Pitnick, Belote, and fellow faculty Steve Dorus and Jannice Friedman to establish the Center for Reproductive Evolution, where they are delving into comparative genomics on a massive scale. Thanks to the computing power of the Orange Grid network, they are analyzing thousands of genes, gene by gene, for 27 species of Drosophila and 23 species of primates. Pitnick is excited about the center’s collaborative environment and the potential it holds for research. “Nobody has done this before, and this is the right place to do it,” he says. —Jay Cox

 

Photo by Steve Sartori