A groundbreaking study published in BMC Biology titled “Building an eDNA surveillance toolkit for invasive rodents on islands: can we detect wild-type and gene drive Mus musculus?” reveals the development of a shovel-ready method to detect mice in the environment and a first proof-of-concept that this method could be used in the future to detect mice carrying a gene drive (tCRISPR) from environmental samples. This innovative approach provides a powerful tool for managing invasive rodent populations worldwide by providing a new method for detecting invasive mice and a new ability to monitor specific genetic traits, such as future genetic biocontrol methods, within a population.  

The collaborative research effort involved scientists from the U.S. Department of Agriculture, the School of Biomedicine and Robinson Research Institute at the University of Adelaide, Island Conservation, The Nature Conservancy, and the Department of Anatomy at the University of Otago. Their aim was to develop an eDNA assay capable of detecting Mus musculus, commonly known as house mice, which are a significant threat to island ecosystems and an eDNA assay to monitor the relative abundance of gene drive mice in a population from passively collected environmental samples.  

The study demonstrates the successful development of an eDNA assay that can detect the presence of Mus musculus in environmental samples. This method provides a new tool to work alongside other tools used in detecting invasive mice on islands, in ports, and other areas. The study also demonstrated the ability to detect a theoretical gene drive (tCRISPR) mouse tested in lab mice at the University of Adelaide. This breakthrough method enables the monitoring of changes in the density of the target species and the spread of the gene drive in populations. It represents a significant step forward in genetic biocontrol, a promising approach for eliminating or modifying invasive populations. 

“The more tools we have to detect invasive species, the better we can manage them,” lead author Antoinette Piaggio from the U.S. Department of Agriculture’s National Wildlife Research Center stated. “This study first and foremost provides a validated eDNA tool for detecting invasive mice. Secondarily, this paper explores monitoring of emerging technologies. Although there is no gene drive mouse, investigating the possibilities of how to monitor gene drive or another gene editing technology and provides potential avenues to biosecurity for such methods that might help us achieve conservation success where we currently cannot.”  

Invasive species management strategies vary from preventing new incursions to eliminating established populations, all of which require effective monitoring to guide action. The use of eDNA as a passive sampling tool offers a non-invasive and efficient means of surveilling and monitoring target invasive species. With the development of this new eDNA assay, conservationists and wildlife managers now have an additional tool at their disposal to combat the threat of invasive rodents. 

“Prevention is always better than the cure when it comes to invasives on islands. But we need to build a better toolbox,” said co-author Dr. Nick Holmes, lead for The Nature Conservancy’s Island Resilience Strategy. “Environmental DNA offers powerful way to detect harmful invasive species like rats and this research is a foundational step forward in building practical, cost-effective tools to protect islands.” 

The study’s findings have far-reaching implications for conservation efforts and highlight the importance of responsible technological advancements in the field. To date most applications of eDNA have focused on detecting the presence or absence of specific species. By using multiple, highly specific eDNA assays together, managers now have new tools to monitor specific genes in a population which could be applied to a broad array of future use cases, such as monitoring the efficacy of emerging synthetic biology tools, the prevalence of genetic resistance to removal methods, or genetic markers associated with disease.   

“Environmental DNA is providing new insights not previously possible,” said co-author David Will, Director of Impact and Innovation for Island Conservation, a nonprofit dedicated to restoring islands for nature and people worldwide by removing invasive species. “Not only can we now detect the presence of mice on an island by sampling as little as a single leaf, we can also now monitor the spread of specific genes, such as future gene drives, within that population over space and time. This research paves the way for more effective and targeted invasive species management, ultimately safeguarding fragile ecosystems and biodiversity, and building climate resiliency for island communities.” 

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Interviews available upon request 

DOI: 10.1186/s12915-024-02063-0

Paper: “Building an eDNA surveillance toolkit for invasive rodents on islands: can we detect wild-type and gene drive Mus musculus?”

Photos courtesy of Island Conservation: https://drive.google.com/drive/folders/1mOcmahDlOdL-fANi8Vnnb08_FHovSMb3?usp=sharing  

Media Contact:

Island Conservation
Sally Esposito, Strategic Communications Director, sally.esposito@islandconservation.org
Bren Ram, Communications Manager—Projects, bren.ram@islandconservation.org 

USDA-APHIS
Tanya Espinosa, Public Affairs Specialist, Legislative and Public Affairs, tanya.c.espinosa@usda.gov, Phone: (301) 851-4092 

About the Partners:

USDA: The USDA provides leadership on food, agriculture, natural resources, rural development, nutrition, and related issues based on public policy, the best available science, and effective management in the United States. 

Island Conservation’s mission is to restore islands for nature and people worldwide and we collaborate with local communities, government management agencies, and conservation organizations on islands with the greatest potential for preventing the extinction of globally threatened species. Island Conservation is a United States-based 501(c)(3) charitable organization that restores islands by removing introduced, damaging invasive species and accelerating the recovery of native plants and animals. We utilize innovative technology and techniques to work more efficiently and showcase the many benefits of holistically restored islands for biodiversity, climate resilience, ocean health, and sustainable development across the globe. Visit us at islandconservation.org.    

The Nature Conservancy is a global conservation organization dedicated to conserving the lands and waters on which all life depends. Guided by science, we create innovative, on-the-ground solutions to our world’s toughest challenges so that nature and people can thrive together. We are tackling climate change, conserving lands, waters and oceans at an unprecedented scale, providing food and water sustainably and helping make cities more sustainable. The Nature Conservancy is working to make a lasting difference around the world in 81 countries and territories (40 by direct conservation impact and 41 through partners) through a collaborative approach that engages local communities, governments, the private sector, and other partners. To learn more, visit nature.org or follow @nature_press on X.