Gene-drive strategy could suppress invasive mice on islands

Invasive rodents pose a significant threat to global biodiversity. Current control methods, such as poisoning, trapping, biological control with additional introduction of competitors or predators are often ineffective, costly, and not species specific. Genetic biocontrol has considerable potential to control invasive populations but has not been developed in any vertebrate pest species.

Revolutionary gene drive technology findings were released in the prestigious journal Proceedings of the National Academy of Sciences. Researchers from University of Adelaide, including Environment Institute's Dr Aysegul Birand, A/Prof Phill Cassey and Dr Thomas Prowse have developed a world-first proof of concept for the technology – called t-CRISPR - using laboratory mice. t-CRISPR is a suppression gene drive strategy for mice that leverages a naturally occurring element with biased transmission (t-haplotype) with additional CRISPR components that spread faulty copies of a female fertility gene. Once the population is saturated with the genetic modification, all the females that are generated will be infertile. Using sophisticated computer modelling, the researchers show that 256 gene-modified mice could eradicate an island population of 200,000 mice in around 20 years.

Significant progress has been made in genetic biocontrol of insects and this work will be invaluable toward developing genetic biocontrol in mice. Successful eradications on islands have been shown to have great impact restoring island biodiversity. t-CRISPR technology provides a humane approach to control invasive mice without the release of toxins into the environment. Biodiversity restoration will make ecosystems and their communities more resilient in the face of climate change and other stressors.

The University of Adelaide research team had worked closely with the Commonwealth Scientific and Industrial Research Organisation (CSIRO), the Centre for Invasive Species Solutions and the Genetic Biocontrol for Invasive Rodents (GBIRd) consortium to consider next steps towards safely implementing the new technology. They are currently working on strategies to prevent failed eradication due to the emergence of gene drive resistance in the target population. Consideration of societal views and attitudes is integral to their ongoing research relating to this gene drive.

Grant information: This research was supported by the Government of New South Wales, the Centre for Invasive Species Solutions, and the Government of South Australia. This research was also supported in part by the USDA Animal Plant Inspection Service, Wildlife Services, National Wildlife Research Center.