WESTERN PRODUCER — A little help from gene editing could force invasive wild pigs to breed themselves out of existence, says a researcher from the University of Guelph.
“I do believe this is a potential solution,” said Ray Lu, associate professor in the university’s molecular and cellular biology department.
Why it matters: Concern over the Prairies’ growing wild pig population kicked into top gear in recent years as farmers worry they’ll see similar economic losses as their counterparts in the U.S., or that the invasive species will become a reservoir for disease.
Western Canada’s wild pig problem has garnered a lot of attention since the late 2010s, when research out of the University of Saskatchewan highlighted an extensive range for the species.
Sightings in subsequent years were often noted by the University of Saskatchewan’s Canadian Wild Pig Research Project spearheaded by Ryan Brook. They indicated hot zones in northeastern Saskatchewan, northwestern Alberta and southwestern Manitoba, particularly around Spruce Woods Provincial Park.
Sporadic reports also accumulated further east in the province. According to a map of reports collected throughout 2023 by Squeal on Pigs, an anti-wild swine campaign launched in Manitoba in 2022, sightings were noted as far east as the RM of Piney, near the Ontario border.
It’s a problem Canadians made for themselves.
In the 1980s, Eurasian wild boar were introduced to the Prairies for meat production and hunting, according to the Canadian Council on Invasive Species. Some of those pigs escaped or were released into the wild, where they’ve since adapted and thrived.
Wild pigs are considered an environmental and financial menace. They trample and root out plants, damage crops and pasture and prey on bird eggs and small animals. They’re also viewed as a potential vector for lethal diseases like African swine fever.
In Europe, the spread of ASF in wild populations has crossed over to domestic pig barns, leading to quarantines, market disruptions and livestock losses.
The threat has led federal and provincial governments to join forces with pork producer groups to fund control and eradication programs such as Squeal on Pigs.
Those groups face a difficult fight. Wild pigs are elusive, hardy, adaptable and quick to reproduce. Hunting is not the answer, experts have said, because shooting a group of wild pigs (called a sounder) just serves to scatter them, multiplying the problem and leading those animals to adjust behaviour that makes them even more difficult to control.
Instead, people are urged to report sightings so an entire sounder can be eliminated using specialized tactics and traps.
Genetic control mechanism
Lu and his team figure there might be an easier way. In a feasibility study, they found they could edit the pigs’ genome so any female offspring would be sterile.
“The males carry this gene and continue to mate,” Lu said. “Therefore, every time the male mates with a female, that’s a dead end.”
Eventually, there would be no more fertile females, and the problem would be eliminated.
The idea came from a similar project with a malaria-carrying mosquito species, Lu said. In 2018, a team from Imperial College London published research saying they had crashed a trial population of mosquitoes by editing their genome so female mosquitoes displayed both male and female characteristics, failed to bite and didn’t lay eggs.
Lu’s research awaits funding. The next step is to raise pigs with the edited genes. Over about two years, the team would raise two generations of pigs to ensure their genetic changes were successfully passed on. They’d also ensure the pigs are robust enough to survive and compete with other pigs in the wild.
Once pigs are bred and propagated, further steps might include a small, contained release for a field study.
Could it escape?
It’s not a scheme with automatic buy-in, Lu acknowledged. Gene editing can trigger fear and debate with the general public.
“The question we got immediately is, ‘well, OK, how will you contain them?’” Lu said. “First of all, this is not a virus. It cannot spread from pigs to other animals. You can only spread it by mating.”
Because female offspring of the gene-edited pigs are sterile, the trait wouldn’t spread quickly, he added.
He also said it’s unlikely the trait would spread to domestic pigs. If a wild pig mated with a domestic sow and a domestic boar received the trait, any female offspring would be sterile and would quickly be culled.
DNA testing could also determine whether a pig carried the edited gene.
Can researchers release gene-edited pigs into the wild? The rules are unclear and it’s unknown which federal department would be responsible for regulation, Lu said. Given that wild pigs don’t respect national borders, U.S. approval would likely be needed as well.
Lu maintains that it’s better to complete the research while waiting for regulations to catch up. That would also give researchers time to raise public awareness about gene editing.
“Hopefully, during this two to three years, public perception will change. I think that momentum is building, that people are more receptive to this kind of technology. I think this is something that Canada should do… We need to develop the tools to be ready.”
Could it work?
Lu said some hog industry groups are on board. In a statement, the Manitoba Pork Council confirmed that, while it hasn’t pledged funds, it has provided background assistance.
“I think the fact that we’re pursuing all different types of research is a really good thing,” said Wayne Lees, co-ordinator for Squeal on Pigs in Manitoba. “We don’t want to really discount any options.”
The invasive species has no natural predators, he noted.
“From an ethical point of view, I don’t see any real issues with it. From a practical, implementation point of view, I think there are challenges.”
The gene-edited pigs must be able to survive in the wild, he stressed. Current understanding of wild pig behaviour assumes strong territorial aspects, and it may be difficult to integrate new pigs into the existing herd.
Given the environmental and animal health risks posed by wild pigs, however, Lu suggested it’s worth a try.
“We are dealing with a problem that needs a solution,” he said.
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About the Author
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