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Sebastian Kvist: Studying Worms and Leeches at the Museum

Education posts

On September 30, 2013, the first graduates of the Richard Gilder Graduate School will receive Doctor of Philosophy degrees in Comparative Biology at the inaugural commencement for the program, the first Ph.D.-granting program for any museum in the Western hemisphere. Over the next several weeks, we’ll profile the newly minted Ph.D.s.

Growing up in the seaside city of Helsingborg, Sweden, Sebastian Kvist was fascinated by water—and the living organisms in it. 

Sebastian Kvist

Sebastian Kvist at the Museum

© AMNH/D. Finnin


Kvist, who remembers spending much of his childhood staring at the exotic offerings of local fishmongers, credits his love of science to his parents, who encouraged heated debates at the dinner table, but only if they were backed by actual observations. 

“I enjoyed these discussions and, in retrospect, I can see how they shaped my critical thinking,” Kvist said. “It might come as no surprise that both my mother and my only brother hold Ph.D.s in obstetrics and gynecology and cell and molecular biology, respectively.”

Having studied marine oligochaetes (relatives of earthworms) as an undergraduate, Kvist began the journey toward his own Ph.D. in 2008, when he came to the Museum as part of the first class in the Comparative Biology program at the Richard Gilder Graduate School. Over four years, he studied organisms ranging from bacteria to perplexing groups of oceanic invertebrates, using microscopy and advanced imaging and DNA sequencing techniques.

The author of 11 scientific publications while in graduate school, Kvist wrote his thesis about the evolutionary relationships of segmented “worms”—bristle worms, earthworms, leeches, and their close relatives, all called annelids—and the symbiotic relationships that some have with bacteria.  

Kvist focused primarily on medicinal leeches, which have adapted to feed exclusively on blood via the evolution of extremely potent anticoagulants, or blood-thinners.

Sebastian Kvist: Leech in Baja California Sur

Photo © Alejandro Oceguera-Figueroa


In addition to being important from an evolutionary standpoint, studying how leeches circumvent the blood-clotting mechanisms of their hosts could be used one day to develop anticoagulants and tumor inhibitors in humans. Mark Siddall, a professor at the Richard Gilder Graduate School and curator in the Museum’s Department of Invertebrate Zoology who is one of the world’s most authoritative experts on leeches, was Kvist’s advisor.

Kvist conducted much of his research during field expeditions to Mexico (pictured below), Canada, Sweden, and Washington and New Jersey in the U.S. 

Sebastian Kvist (Baja California Sur)

Sebastian Kvist in Baja California Sur 

Photo © Alejandro Oceguera-Figueroa


“Most people think that leeches only occur in stagnant foul-smelling swamps or polluted waters but this couldn't be further from the truth,” Kvist said. “Leeches normally need clean, and sometimes flowing, water. That said, some of the places where we've looked for leeches are no place to go for vacation. I have been waste-deep in stagnant lakes in several places on several continents.”

Prior to enrolling at the Richard Gilder Graduate School, Kvist received a bachelor’s degree and master’s degree in biology from Sweden’s University of Gothenburg and a certificate in conservation biology from Lund University, also in Sweden.

Sebastian Kvist Ph.D. Defense with Mark Siddall and John Flynn

Sebastian Kvist (center), with his advisor Mark Siddall (left), and John Flynn, dean of the Richard Gilder Graduate School at Kvist's dissertation defense. 

© AMNH/C. Chesek


Now a researcher at Harvard University, Sebastian Kvist was the first student to successfully defend his dissertation, on May 25, 2012. 

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