Dingoes are genetically distinct from domestic dogs and their evolution has been shaped by Australia’s environment, scientists who have fully decoded the dingo genome have said.
An international team of researchers have analyzed the genetic makeup of a pure desert dingo called Sandy Maliki, finding that dingoes are an intermediary between wolves and domestic dog breeds.
Sandy, with her sister and brother, was discovered as a three-week old pup in the central Australian desert. In 2017 she won a “world’s most interesting genome” competition which funded the DNA sequencing.
The researchers compared Sandy’s genome to that of five domestic dog breeds – a basenji, a boxer, a Labrador retriever, a German shepherd and a great dane – as well as a Greenland wolf.
Using five types of DNA sequencing technology, as well as epigenetic analysis, the researchers found distinctions between the dingo genome and that of domestic dogs.
One was a difference in the number of copies of a gene coding for amylase, an enzyme which aids in digesting starchy food. Dingoes, like wolves, only have one copy of the amylase gene.
“Breed dogs, which only emerged in the last 200 years, have between two and 20 copies of this gene,” said Matt Field, an associate professor at James Cook University and the study’s first author. “That’s one of the telltale signs of domestication and [in dingoes] it’s not there.”
Study senior author Prof Bill Ballard, of La Trobe University, said when humans first began domesticating dogs, they fed the animals rice products, which are high in starch – creating a selective pressure for dogs with multiple copies of the amylase gene. “Those dogs that did better with the rice were… more likely to be associated with humans over time,” he said.
Ballard said some scientists had previously thought that “dingoes had lost the ancestral duplications of amylase”.
“That was not true. We could look at the signature of the genome and say: no, there’s only ever been one copy of amylase in the dingo, just like the wolf.”
The difference could have significant conservation implications, Ballard said. “If a pure dingo eats very different things to a wild dog, then it’s going to have a different position in the ecosystem and … be differentially attracted to different foods.”
The decoded dingo genome could also have veterinary applications for domestic dogs, Ballard said. He believes it could be a genetic reference for canine diseases as “rather than another inbred dog that you’re comparing it to, you’re comparing it to a healthy outbred animal”.
The team also analyzed dingo and German shepherd scat, finding differences in their microbiomes, including that the domestic dog had higher concentrations of three bacterial families involved in breaking down starchy foods.
Dr Kylie Cairns of the University of New South Wales, who was not involved in the study, said the microbiome differences could “explain why we are not seeing feral dogs in Australia”. Her previous research by her has suggested that most wild dogs killed across the country are pure dingoes or dog–dingo hybrids.
“[Dingoes] are older than the oldest domestic dog breed, which is the basenji. Their results clearly demonstrated that,” she said. “Dingoes are a wild canid that has been shaped by Australia’s climate and ecology over thousands of years.”
“The implications of that are that they should be treated like wildlife,” Cairns said. The dingo is “the only native animal that is baited and killed across national parks and conservation reserves” in Australia, she added.
“We need to respect their place as the apex predator in Australia, because they have an important ecological role,” Cairns said. “We need to figure out a better way of coexisting with them so that we can have agriculture of livestock – particularly sheep – but that we continue to have dingoes in the environment.”
The scientists now plan to find out whether the dingo has ever been domesticated, and also to sequence the genome of the alpine dingo and the Fraser Island dingo. This will help them better understand crossbreeding with dogs and what effect it might have on the animals’ behavior and role in the ecosystem, Field said.
The research was published in the journal Science Advances.