Evolution work

Edwards eager to expand the work of the father of evolution

It’s been 186 years since Charles Darwin collected the species samples from the Galapagos Islands that led him to explain how the diversity of life on Earth evolved and forever changed the way we understand the world.

During his five-week stay on the islands, Darwin collected dozens of specimens, including a small light brownish-gray snake on Floreana Island. This specimen, now in the Natural History Museum in London, served as the basis for the description of a new species, the Galapagos racer (Floreana).

The species has disappeared from Floreana but can still be found on two satellite islands. Now UC Merced’s Evolutionary Biology and Conservation Genetics Professor Danielle Edwards and his research group are the first scientists to propose the genetic sequencing of Darwin’s original Galapagos racer sample. Edwards recently obtained a 2020-2021 Research Publication Grant in Engineering, Medicine, and Science through the American Association of University Women (AAUW) to study Galapagos snakes.

“We want to perform ecosystem restoration on Floreana Island by finding an evolutionary replacement in the ecosystem for this species. populations on other islands. We can then use the closest genetic relative to repopulate Floreana Island with this key predator,” Edwards said. “We will also use this dataset to understand the extent of diversity of species in the archipelago with the most extensive sampling to date.”

Anecdotally, Racers have fallen prey to cats and other invasive species across the islands. Edwards and his team will use genetic data collected from samples collected by Galapagos National Park and numerous international collaborators, as well as museum specimens, to assess changes in population size in racer populations and see if populations are declining or stable, informing future conservation management efforts by Galápagos National Park.

“It’s a huge effort, involving an international team of collaborators, and we don’t know yet if we’ll be able to get the DNA from the specimen that Darwin collected,” Edwards said. “But we won’t know unless we try, and results from other similar studies in museum specimens have shown promising results.”

The Galapagos is a prime location to undertake conservation and reseeding research, as the park has a long history of integrating rigorous science into practices with many partner organizations, she said.

Edwards will lead a team – including colleagues from the US, UK, Ecuador and New Zealand, as well as Galapagos National Park and Islands Conservation – to develop the project. They have collected samples over the past five years to try to identify new species on the islands and expand the sampling to include all known islands and islets where the snakes occur.

“The results of this research will provide a detailed picture of how snakes evolved across the islands. Snakes are the latest group of reptiles to have their historical movements across the islands studied. They are thought to be the most mobile of terrestrial vertebrates and therefore more likely to provide information about connections between islands,” Edwards said. “This project will also provide a source population for Floreana regeneration and a detailed assessment of the genetic health of snake populations across the islands.”

Edwards, who joined the Department of Life and Environmental Sciences in the School of Natural Sciences as of 2015, focuses most of his research on the impact of the environment on the evolution of the ecological niche, phenotype and behavior of reptiles, primarily in the context of how these changes lead to the development of new species . She applies this research to inform conservation management strategies for endangered and vulnerable reptiles and amphibians.

But this is not his first genetic project in the Galapagos. In 2015, a team she was part of revealed that they had identified a new species of giant Galapagos tortoise. Edwards carried out much of the genetic analysis of the populations, using repeated fingerprint markers like those used in forensic research, which allowed the team to distinguish between two closely related species. She has been involved in projects in the Galapagos and Australia applying genomic techniques to understand biodiversity and implement conservation management for the past 20 years.

“Working in Galapagos is a dream come true for an evolutionary biologist, herpetologist and conservation biologist,” she said. “I feel privileged and excited to work on a project based in the crucible of evolutionary thought with a specimen that Darwin himself collected.”