World’s First Sequenced Dingo Genome Shows They Differ From Domestic Dogs

A new study has, for the first time, sequenced the genome of the Australian desert dingo, a wild dog that has been geographically isolated from both wolves and domestic dogs for thousands of years. Researchers, led by La Trobe University’s Prof. Bill Ballard, showed that there are structural differences that separate the dingo genome from that of breed dogs and that those changes have implications for the dingo’s physiology and even its gut microbiome.

Top dog in Australia

Dingoes play an important role in the Australian ecosystem. “Dingoes are Australia’s ‘top order predator’, meaning they influence everything in their environment,” explained Ballard in a press release.

Despite this, the origin of dingoes remains unclear. Is the dingo essentially a feral dog or a distinct canid that has remained untamed? This debate fueled the current study, which analyzed a genome taken from a pure wild dingo—crossbreeding with domestic dog has created many dog–dingo hybrids—named Sandy. The funding to sequence Sandy’s genome only arrived after the she won a contest to find the World’s Most Interesting Genome in 2017.

Sandy’s genome was assembled using a selection of techniques, producing a sequence 2.35 billion bases long. The genome was then compared to that of five breed dogs that represent the spectrum of domesticated canids: the German Shepherd, Boxer, Labrador, Basenji and Great Dane.

To create an evolutionary tree involving domestic dogs and the dingo, a reference genome is needed that is genetically different from the animals under study—this is called an outgroup. Here, the authors picked the Greenland Wolf as outgroup—a subspecies that predates both dogs and Eurasian wolves and has mixed very rarely with other canid populations.

Dingo–Dog differences

The analysis showed that the dingo genome, isolated from other canids in Australia, had diverged from domestic dog breeds, showing up to 24 million unique bases as compared to domestic breeds.

There were at least three large chromosomal differences noted between Sandy’s genome and that of the reference dog genome, which is taken from a Boxer breed. One substantial difference, identified in a previous study, was that the dingo genome had only one copy of a gene coding for an enzyme in the pancreas called amylase. Domestic dogs have multiple copies of this gene, which functionally assists in starch digestion. 

The authors wanted to explore whether genomic differences like this would have effects on the canids’ physiology. They noted that some gene transcripts related to nutrient metabolism, like that of GAL3ST1, were more highly expressed in the dingo versus breed dogs.

To test whether these changes would impact how the canids metabolized food, they examined a group of 17 dingoes and 15 German Shephard dogs (the breed with most genomic similarity to the dingo) over a period of 15 days. The animals were treated with an antibiotic and then given a probiotic to minimize differences in their microbiome. They were then fed a similar diet for the duration of the experiment (two of the dingoes spiced up their palate by devouring an unfortunate possum that fell into their enclosure during the experiment). This analysis confirmed that amylase was reduced in the dingoes at the end of the study, and their cholesterol and low-density lipoprotein levels were significantly higher. Microbiome analysis also suggested differences between the domestic dogs and the dingoes.

Ultimately, the authors concluded that their evidence suggests the dingo genome has “diverged substantially” from that domestic dog, although they note that these canids all remained relatively similar when compared to the Greenland Wolf.

Are dingoes to blame for livestock loss?

They also argue that the genomic and metabolic differences between dingoes and domestic dogs could have implications for how dingoes are managed in Australia. Dingoes and wild dogs are seen as synonymous in Australia, where they are also regarded as a threat to grazing livestock. Ballard says their data implies that dingoes have instead evolved to eat native Australian species, such as marsupials and reptiles. “Based on this new knowledge, we hypothesize that dingoes are far less likely to eat farm animals, including sheep. If we’re correct, what farmers currently assume are dingoes killing their stock, are likely to be feral wild dogs,” said Ballard.

As dingoes are an apex predator in Australia, Ballard suggests that overzealous dingo control could have major ramifications for Australian ecosystems: “If dingoes aren’t given the protection they deserve, it will upset the country’s ecological balance—potentially leading to environmental issues like erosion and species extinction.”

There are still unanswered questions about the dingo. The team call for more detailed analysis of pure dingoes in their ecosystem. But their research does show the power of genomics to unravel mysteries about Earth’s most iconic animals. “It gives us much clearer insight into how the dingo evolved – which is fascinating from a scientific point of view, but also opens up all sorts of new ways to monitor their health, and ensure their long-term survival,” concluded Ballard.

Reference: Field MA, Yadav S, Dudchenko O, et al. The Australian dingo is an early offshoot of modern breed dogs. Sci. Adv. 2022; 8. doi: 10.1126/sciadv.abm5944