New research suggests dingoes don't have much dog ancestry and are more purebred than researchers thought.
The research suggested genetic analysis of dingo populations showed that dingoes have less dog lineage and there are more purebred dingoes in the wild.
The study indicated that previous research had overestimated the number of dingo-dog mixes and the lethal methods used to control "wild dogs" in Australia were actually controlling pure dingoes.
The research suggested hybridisation can threaten a pure species as it can become vulnerable to extinction by genetic dilution.
"For decades, there was fears that dingoes were breeding themselves into extinction. But our findings suggest this isn't the case, and dingoes are largely maintaining their identity, which has implications for their management and conservation," said lead author of the study and conservation biologist Dr Kylie Cairns said.
More pure dingoes than hybrids
Researchers used a new genome-wide test to analyse the DNA of 391 wild and captive dingoes in different regions across Australia.
They conducted detailed ancestry modelling and biogeographical analysis to find wild dingoes had far less dog ancestry than suggested by prior genetic studies.
"The old method, which relied on a relatively small number of genetic markers and limited reference population, overestimates the amount of dog ancestry in dingo samples – sometimes by over 30 per cent," Dr Cairns said.
The University of Sydney's Professor Chris Dickman said before researchers had decent genetic techniques, "it was feared that wild domestic dogs were making such inroads into the dingo population by interbreeding that 'pure' dingoes would soon go extinct.
"As iconic Australian outback animals, that was an issue of considerable concern. The new research shows that those fears were misplaced, fortunately!"
Dr Cairns said because the old method often identified an animal as a crossbred when it was in fact a purebred or a historical backcross.
"With the new test, we can look at 195,000 points across the genome compared with just 23 previously. So, it's a huge step up in reliability and accuracy."
In Victoria, where previous reports suggested the pure dingo population was as small as four per cent, the new study found 87.1 per cent of animals tested were pure dingoes and 6.5 per cent were historical dingo backcrosses with more than 93 per cent dingo ancestry
In New South Wales and Queensland, where dingo-dog hybridisation is assumed to be prevalent, most animals were also found to be pure dingoes, and only two wild canids had less than 70 per cent dingo ancestry.
Northern Territory, South Australia and Western Australia also had little evidence of hybridisation amongst the dingo population.
Dr Cairns said the outdated DNA testing methods has led researchers to believe dingo-dog hybridisation is more common in Australia than it actually is.
"Most dingoes in the wild are pure dingoes, and the remaining animals are more dingo than anything else," she said.
"Even in the parts of Australia where dingo-dog hybridisation is higher, it is not the pervasive threat we've been led to believe."
None of the animals from the research sample were 50 per cent hybrid, so none were direct offspring of a dog and a dingo in the wild.
The small number of animals that weren't pure dingoes were mostly historical backcrosses with a single dog ancestor four or five generations in the past.
"While there has been some hybridisation in the past, it's not occurring at a rapid pace today," Dr Cairns said.
The study also found significant regional variation in dingoes, with four distinct wild dingo populations across mainland Australia.
"There's also a chance some dog DNA has been integrated into the dingo genome because it's provided an evolutionary advantage, so that's something we plan to investigate in future research using the new testing," Dr Cairns said.
When asked by the ABC what stood out to him about the findings, Professor Dickman said "the widespread continental nature of the sampling and the uniformity of the spread of the dingo genotype, but also the identification of the five dingo-ecotypes".
The findings are consistent with studies in other species demonstrating genome-wide analysis performs more accurate identification of ancestry, which policy makers can use to inform dingo management.
Senior author of the study and conservation biologist Mike Letnic said the new genome-wide testing will be able to help get a more accurate representation of dingo populations.
"We now have a more advanced approach using higher-density genomic data that can be applied to dingoes to assess populations more accurately and inform management strategies with best-available evidence."
Dingo management
The term "wild dog" is widely used under the assumption there is widespread dingo–dog hybridisation and very few pure dingoes remain in Australia.
Under the name "wild dog" --- dingoes, dingo-hybrids, and feral domestic dogs are all considered invasive species.
"Wild dogs" are under biosecurity legislation and subject to eradication measures like aerial baiting or trapping across parts of the Australian mainland, including National Parks where native animals are protected.
"It's convenient to paint all dingoes as wild dogs. But the term obscures the reality that many pure dingoes and dingo-dominant backcrosses are being killed," Dr Cairns said.
"In fact, no other native species is treated in quite the same way as the dingo, which is subject to lethal control measures across all landscapes, including ones where they should be protected."
The research suggested environments without dingoes can get overrun by kangaroos, foxes and feral cats that threaten other native animals and can change vegetation significantly.
"Dingoes are a threat to some livestock, but they're not a pest in all contexts. They play a crucial role as apex predators in maintaining ecosystem function and biodiversity," Professor Letnic said
He said a balance was needed so people can maintain populations of the dingoes.
Lethal control methods, particularly during dingo breeding season, may inadvertently increase the risk of hybridisation by reducing the availability of pure dingoes.
However, more research is needed to confirm the link.
"While we don't have many hybrids running around like previously suggested, where dingo-dog hybridisation does occur, it's in regions where intensive lethal control is used and where there are higher numbers of domestic pet dogs," Dr Cairns said.
The researchers suggested the definition of "dingoes" in conservation policy should be revised to include historical dingo backcrosses with 93 per cent or more dingo ancestry and distinguish them from "feral domestic dogs."
"Doing so will more accurately reflect the identity of wild canids in Australia and acknowledge the value of dingoes as a native and culturally significant species," Dr Cairns said.
