The College of Science is highlighting some of its Ph.D. students in honor of National Dissertation Day, which is April 26.
For as long as Ramses Rosales-Garcia can remember, the natural world has captivated him.
While he was growing up in Jerez, Zacatecas, a small town in Mexico, he was fascinated by animals. Like many future biologists, he spent hours watching wildlife documentaries.
“I really like animals in general,” he said. “As a kid, I wanted to be one of the people who studied them.”
That early curiosity turned into a more specific interest in reptiles and amphibians, especially snakes, after Rosales-Garcia began working with Jesus Sigala, a biology professor who studied snakes, while he was pursuing his bachelor’s degree from Autonomous University of Aguascalientes. After he graduated in December 2015, he worked as a research technician with his undergraduate advisor in the university’s zoological collection.
He later worked briefly as a field biologist with a nonprofit conservation group trying to protect seabirds threatened by feral cats on Socorro Island, part of the Revillagigedo archipelago in Mexico.
Growing interest
But his long-term goal was graduate school. After earning a Fulbright scholarship, he began looking for a place where he could combine his love of snakes with his growing interest in genetics and evolution.
That path led him to Clemson University in 2020, during the height of the pandemic. He did not know much about Clemson when he first applied for the Fulbright program, but that changed after attending a scientific meeting on vipers and snakebite research in Aguascalientes, Mexico. There, he learned about the work being done in the lab of Christopher Parkinson, the director of the Clemson University Genomics and Bioinformatics Facility and a professor in the Department of Biological Sciences.
What drew him in was the fit.
Perfect match
Rosales-Garcia wanted to study venom evolution in snakes. That was exactly the focus of Parkinson’s lab. Rosales-Garcia focused on how venom toxins evolved in pit vipers, the group that includes rattlesnakes, copperheads and cottonmouths. He successfully defended his dissertation in March.
Explaining the work in simple terms, he said snake venom is made up of many toxins that belong to different families. His research focuses on one toxin family that produces especially potent neurotoxins. What makes those toxins so interesting is that they are not found everywhere. Some species have them, some do not and, in some cases, the toxins appear only in certain populations of a species.
Using genomic data, he found that these toxins first originated millions of years ago in an ancestor shared by pit vipers in Asia and the Americas due to a gene duplication. Over time, the toxins were lost in some species but retained in others. A similar toxin appears to have evolved again in a group of Mexican pit vipers through a separate gene duplication event. Additionally, he found evidence of multiple additional duplications of these toxins, followed by gene deletions that modify the genomic architecture across different species.
While the research could help inform future medical studies related to snakebite and antivenom, he says its biggest impact may be in understanding biological processes and the approach to studying them. Knowledge of how toxin genes evolve and acquire new functions will help scientists study other gene families, including those involved in the immune response and disease.
After graduation in May, he will continue that line of work as a postdoctoral researcher at the University of Nevada, Reno, where he will study the gene families involved in toxin resistance. Eventually, he hopes to return to Mexico and become a university researcher or professor.
That goal, he said, reflects the spirit of the Fulbright program: learn, grow and bring that knowledge back home.
