• Academics
Lawrentians Document the Evolutionary History of New Plant Species

Lawrenceville science teacher John L. Clark has discovered (or been part of a team that discovered) dozens of new plants in the New World Tropics (especially South America and Cuba), and any Lawrentian with an interest in botany can examine the DNA samples to document these new species. He leads a year-long organismal evolutionary biology extracurricular that, each trimester, welcomes students from all Forms. All that is required is an interest in science.

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“It's unique. It's fun. And it's possible because we have really bright kids who are motivated. We have samples that no one else has – it’s not every day someone can study the evolution of a plant that is not represented in GenBank and generate original data,” said Clark, who holds a doctorate in evolutionary biology and is an expert on neotropical Gesneriads - tropical plants that are most abundant in the northern Andes.

Clark is the author of several monographic revisions, field guides, floristic studies, and his research has been widely published in scientific journals. Most recently, his joint discovery (with Laura Clavijo from the Universidad Nacional de Colombia) of the longest flower known in the Drymonia genus was published in Phytokeys, a journal of systematic botany. He is a contributor to the Gesneriaceae Resource Center, part of the World Flora Online project.

“We’re generating this data to get a better understanding of the evolutionary relationships between plants because many of them have not been represented in scientific literature,” Clark explained.

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Third Former Raymond Xu said he decided to participate in the program because he’s always been curious about science — particularly biology. “It's really interesting learning about how life works, evolves, and adapts,” he remarked. Alayna Ting ’24 said she signed up because she has a “passion for science. The topic of our study in evolutionary biology sounded really interesting especially since we are in the lab studying it ourselves. I also wanted to get more hands-on lab experience, which this extracurricular provides.”

Twice a week, students meet with Clark and Lab Assistant Stuermer to unlock the evolutionary history and discover patterns of diversification. The samples were either collected by Clark, by Clark and Lawrenceville students on a School-sponsored expedition, or donated to the School through his worldwide contacts with botanists and botanical gardens.

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“We're using DNA sequence data to better understand how species are related to each other – it’s evolutionary based,” he noted. Results require patience and precision. “It’s a multi-month process to put all the data together — it takes a while from PCR (polymerase chain reaction), to DNA sequencing, to generating a phylogenetic tree, to interpreting what that means,” he continued.

Student researchers are divided into smaller groups of three to five to do their work, something Xu has enjoyed. “It has been a really great experience as a Third Former to work in the lab with a lot of people who are juniors and seniors,” he said “It’s given me the opportunity to work with some really great people, and they serve as an inspiration to me. When I get confused about what's going on I don't hesitate to ask them questions, and everyone's been really supportive and nice to me.”

In the course of creating this vital data, Lawrentians are mastering the skills necessary for lab work. “Some of the most interesting things I have learned are how to pipette, how to run PCRs, and conduct electrophoresis,” said Ting. “Before I participated in this program I had no idea what these were, much less how to do them [and now I’m using them] these to analyze DNA samples.”

Early days in the lab were challenging, Ting explained. “I struggled at first with pipetting our samples into the wells of the microgel (for electrophoresis) because they are quite small and hard to see. However, the experienced group mates were able to give really helpful advice that allowed me to do this successfully.”

Since Clark joined the Lawrenceville faculty in 2015, the findings he and his students (from the extracurricular, as well as in his regular courses, spring/summer trips, and work with the Hutchins Scholars) have been published in several scientific journals and presented at scholarly conferences alongside researchers with decades of experience. “The School has been great about supporting these sorts of opportunities for our kids,” he said.

Ting and Xu both “definitely recommend” the extracurricular to any students with an interest in science.

“You learn a lot and meet great people. “You don't have to be an expert to enjoy your time here, and anyone's welcome to join, no matter what grade you are in,” Xu said.

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For additional information, please contact Lisa M. Gillard Hanson, director of Public Relations, at lgillard@lawrenceville.org.