Cane toads could shag themselves out of existence
AUSTRALIA'S most loathsome residents could be living on borrowed time with a scientific development offering hope cane toads will eventually breed themselves out of existence.
A new gene-editing technology developed by scientists at MIT, known as a "W-shredder" gene drive, is being investigated for its potential in controlling pest species.
The technology works in species in which females carry a W-chromosome - including birds, butterflies and cane toads.
The edited genes would mean the mutant toads produce only sons, eventually leading to an entirely male population that breeds itself into oblivion.
University of Melbourne biologist Luke Holman created a computer program to model what might happen if a group of gene-edited toads was turned loose.
"It chops up the W-chromosome, so they can't have daughters," he said.
"Those sons go on to mate with more females and make more male-only offspring."
Dr Holman's simulation used an assumed population of 100,000.
"Assuming you design it in a certain way, it should work very effectively," he said.
In the best-case scenario, releasing just 20 gene-edited toads could wipe out that population in nine generations, or about nine years.
However because the technology is so effective, it comes with a warning.
While cane toads are unwelcome invaders in Australia, a single toad in the wrong place could destroy native populations.
"If someone accidentally released (a gene-edited toad) in South America … it could be really hard to control," Dr Holman said.
"There is a lot of interest using this technology to control nasty species … but it comes with a lot of ethical and safety concerns."
However Australia's geographical isolation made it the ideal location to try out the new technology, he said.
In 2017, scientists at the University of Sydney and Macquarie University showed Territory cane toads were some of the friendliest around.
The study at the "invasion front" showed they were more likely to seek out their amphibian friends than toads in more established populations.
Lead author Jodie Gruber hypothesised at the time that invasion-front toads hung out to learn from each other.