Kean University Professor Brenna Levine Helps Discover First ‘Virgin Birth’ in Crocodiles

Discovery offers new insight into dinosaur reproduction

A Kean University biology professor co-authored a research paper proving female crocodiles can reproduce without a mate, a finding that sheds new light on scientists’ understanding of crocodiles’ ancestors, dinosaurs.

Assistant Professor Brenna Levine, Ph.D., of The Dorothy and George Hennings College of Science, Mathematics and Technology (CSMT) at Kean, wrote the novel software program that used genomic data to prove “virgin birth” can occur in crocodiles.

“Due to the evolutionary relationship between crocodiles and dinosaurs, our finding makes it very likely that dinosaurs and pterosaurs could reproduce this way as well,” Levine said. “This is a very important evolutionary finding, and it is also basically the plot of Jurassic Park.” 

The crocodile research paper, Discovery of facultative parthenogenesis in a New World crocodile, was co-authored by Levine, a molecular ecologist; Warren Booth, Ph.D., an endowed professor of urban entomology at Virginia Tech; and others on a seven-member team.

Their work made headlines around the world, including in The New York Times, CNN, The Washington Post, and NPR’s Science Friday, and Levine was interviewed on BBC World News. The research was published in the journal Biology Letters.

The research began with a female crocodile in captivity in Costa Rica, which was isolated since it was two years old, but laid eggs. One egg developed a fully-grown, stillborn, embryo that scientists suspected could be a “parthenogen,” born through asexual reproduction.

Tissue from the crocodile mother and embryo was shipped to the research team. Researchers sequenced the DNA, then Levine created the software program to analyze genomes, finding there was no evidence a male crocodile had been involved in the reproduction.

While facultative parthenogenesis, or virgin birth, has been found in birds, snakes and lizards, the crocodile discovery makes it likely that dinosaurs and pterosaurs, and possibly all reptiles, could reproduce that way, Levine said.

“These results move us a long way toward understanding how and when reproductive modes evolved,” Levine said.

Levine, who received her master’s and doctoral degrees at the University of Arkansas, and her bachelor’s degree in wildlife biology from Colorado State University, conducts research in the areas of reproductive ecology and invasive species.

In a separate research project, Levine was awarded a highly competitive research grant from the National Science Foundation (NSF) for $471,223. In that three-year research project, entitled BRC-BIO: Effects of urbanization on the evolutionary dynamics of invasive species range expansion, Levine will lead research at Kean on the role of urbanization in the evolution and spread of the invasive spotted lanternfly.

She will sequence DNA of spotted lanternflies in their native range of China, and in invasive ranges of the U.S. and Japan, to understand how urbanization affects their spread and evolution.

Brian Teasdale, Ph.D., associate dean of CSMT at Kean, said Levine’s research aligns with Kean’s development as a research university.

“Dr. Levine's work helps move Kean University another step further toward its goal of the Carnegie R2, high-research activity, classification,” Teasdale said. “Additionally, Dr. Levine's work on lanternflies and invasive species, which has direct implications for our state and ecosystems throughout the nation, is an example of how Kean has solidified itself as New Jersey's first urban research university.” 

The lanternfly project includes funding for undergraduate research assistants, development of an undergraduate research class and collaboration with students in the Kean Scholar Academy, a pre-college program for high school students on Kean’s campus.

Nicolas Largotta, a junior molecular and cell biology major at Kean, is working on the project.

“I approached Dr. Levine in December, seeking to gain lab experience and learn techniques that could be applied in my career,” he said. “The lab has given me a large amount of experience, introducing me to new techniques and allowing me to see first-hand everything involved in science,” he said. 

Levine posts time-elapsed videos of her research online, using the Twitter handle @BioBrenna.