Noted Hybrid Expert Presents Research

Bridgett vonHoldt, Ph.D., assistant professor at Princeton University, presented her research on hybrids at the 66th Annual Mendel Lecture. Her presentation, “Conservation Genomics: The Role of Hybrids,” outlined her research findings about the genetics of wolves and coyotes, how they form hybrids and the significance of conservation.

Dr. vonHoldt earned a B.S. in psychology from Eckerd College, a M.S. in biology from New York University and a Ph.D. in ecology and evolutionary biology from the University of California, Los Angeles. She completed a postdoctoral fellowship with the UCLA Computational Biosciences Institute. Dr. vonHoldt currently teaches and conducts research in Princeton University’s Department of Ecology and Evolutionary Biology and has authored numerous scientific publications and has received grants from organizations such as the Yellowstone Park Foundation and National Science Foundation.

“I want to shed light on a subject that’s misunderstood,” said vonHoldt who explained that the notion that the word “hybrid” refers to two different species is a misnomer. “The word ‘hybrid’ refers to the offspring produced by inter-type mating,” she said.

However, there is a controversy surrounding hybridity. On the one hand, some scientists believe that hybridization is a potent evolutionary force. For example, in the Monkey Flower, if the flower is a hybrid between the Monkey Flower pollinized by bees and the one pollinized by humming birds, it can produce a vast array of F2s and it is a fast and easy way to create diversity.

“We argue for a more balanced approach that focuses on the ecological context of admixture and allows for evolutionary processes to potentially restore historical patterns of genetic variation,” said Dr. vonHoldt.

On the other hand, there is the view that evolutionary hybrids do not belong. However, deleterious alleles are more probable with in-breeding when species cannot hybrid with each other.

For example, the Florida Puma was nearly extinct until scientists decided to create a hybrid to increase the survivalship of future generations.

“Have we lost the distinctive genome of the Florida Puma?” asked Dr. vonHoldt, because now the once “pure” Florida Puma is an admixture of other panthers. “We still don’t know what to do with hybrids—it is being dealt with on a case-by-case basis.”

Using the first half of her presentation as a foundation, Dr. vonHoldt then progressed to her research, which deals with the hybridization of wolves and coyotes. Her research is an ongoing project where she explores the genetic consequences of admixed ancestry in the context of selection and the impact on an expanding species range. She developed a test to determine how much the hybrid relates to each of its parents. She looks at the entire genome and that has not been done before and then makes predications in an attempt to save endangered species such as the red wolf, which she came to found out had very little similarities with the wolf. This discovery presents problems because some types of wolves are protected under the Endangered Species Act but coyotes are not. She discussed her research with visual reinforcement, using graphs, charts and illustrations to show her findings.

“Dr. Bridgett vonHoldt’s presentation complemented and expanded upon many of the topics we teach at Saint Peter’s in courses like general biology II, genetics and ecology. She provided a fascinating overview of the history of gray wolves and coyotes in North America. Her research has shown that the two species have extensively hybridized in the eastern part of the United States, forming the eastern wolf in the Great Lakes region and the red wolf in the southeast. Her research also revealed a number of surprises, including the fact that the red wolf is not really a wolf at all because genetically it turns out to be about 80% coyote! Her findings have important implications for the management of endangered species,” said Katherine Wydner, Ph.D., associate professor in the biology department and health careers advisor.

“In conclusion, the Endangered Species Act views the animal kingdom as a tree of life, where everything is one branch and nothing loops back around. What we are promoting is the web of life,” said Dr. vonHoldt.

The Mendel Lecture is the longest running annual lecture series at Saint Peter’s University and is coordinated by the Mendel Biology Society, the biology department and the applied science and technology department. A generous gift from Michael Filosa, Ph.D. ’53 made the 66th Mendel Lecture possible. Learn more about vonHoldt’s research at and