Many people I know that modern dogs evolved from the gray wolf. But did you know that most of the more than 340 modern dog breeds we have today only appeared in the last 200 years?
Dogs were first domesticated during the Neolithic period, between 29,000 and 14,000 years ago, and have been closely linked to humans ever since. Dingoes – the only native Australian dog – are believed to represent a unique event in canine evolution, having arrived in Australia 5,000 to 8,000 years ago.
However, the exact place of dingoes in the evolutionary family tree of dogs has never been known. To find out where they drifted away from gray wolves on their evolutionary journey, we used cutting-edge DNA sequencing technologies to discover that dingoes are fundamentally different from domestic dogs.
In research published in advances in science, in collaboration with 25 researchers from four countries, we showed that dingoes are an early offshoot of modern dogs situated between the gray wolf and today’s domesticated dogs. This work has potential health implications for all dogs of modern breeds.
The dog and human history
By studying dogs, we can gain insights into how we, as humans, influence their physical and behavioral characteristics, as well as observe changes in their genome.
For example, dogs have only recently developed the ability to raise their eyebrows – a trait likely developed to communicate more effectively with humans. So it looks like puppy dog eyes were really “created” just for us.
But some examples are not so obvious and can only be found by looking deeper into the genomes of dogs.
For example, previous scientific studies have shown that dogs need a specific gene (amylase 2B) to digest starch. Many dog breeds carry multiple duplicates of this gene, sometimes more than 10 copies. However, the wolf and dingo only retain a single copy of this gene.
This duplication in modern dogs likely resulted from a change in the diet of early domesticated dogs, as they were increasingly fed starchy foods such as rice (grown through early widespread agriculture).
Interestingly, the same gene duplication occurred independently in other recently domesticated domestic animals, indicating how humans can affect the genomes of domesticated animals.
Are dingoes an early offshoot of modern dogs?
Dingos are unique in that they have been geographically isolated from wolves and domestic dogs for thousands of years. In our study, we used genetics to help us understand exactly where the dingo fits into the evolution of dogs and what role it plays in the Australian ecosystem.
Initially, in 2017, we only had access to a single dog genome as a point of comparison (a boxer breed). It contained many gaps, due to the limitations of the technology at the time.
However, that same year, the dingo won the “World’s Most Interesting Genome” competition, held by the American biotechnology company Pacific Biosciences. This got us thinking about generating a high quality dingo genome.
But to understand the dingo’s place in dog history, we also needed several high-quality dog genomes. Thus, we generated a German Shepherd genome as a representative breed, followed by the basenji (one of the first dog breeds, used for hunting in Congo).
Finally, we were able to sequence the genome of a pure desert dingo calf, Sandy, found abandoned in the wilderness.
The ability to generate high quality genomes has only become possible in recent years, due to the development of long reading sequencing technology. This technology was also crucial to the recently announced completion of the entire human genome.
Using our new dog genomes – along with existing genomes from the Greenland wolf and other representative species including the Great Dane, Boxer and Labrador – we measured the number of genetic differences between these breeds and the dingo to definitively show where the dingo fits into the world. evolutionary timeline.
We found that dingoes are actually an early offshoot of all modern dog breeds, between the wolf and the domesticated dogs of today.
future work – Collectively, our analysis shows how different demographic and environmental conditions shaped the dingo genome. We cannot say for sure if the dingo was ever domesticated, but we do know that it is unlikely that it was domesticated after its arrival in Australia.
Future work on more dingo genomes will address whether the dingo has ever been domesticated and will also measure the level and impact of pure dingo crosses with domestic dogs. Although many hybrid dingoes are similar in appearance, there have been substantial crosses, particularly in New South Wales and Victoria.
This knowledge is important. A better understanding of the effect of interbreeding dingoes with dogs can provide insights into the role of dingoes in the ecosystem and therefore help in future conservation efforts.
Additionally, knowledge about the evolutionary history of dingoes helps us understand how and when domestic dogs evolved alongside humans and can help us identify and target new ways to improve their health and vitality.
Veterinary applications — Through artificial selection, humans have been selectively breeding dogs for desirable traits and traits for hundreds of years.
While this created modern purebred bloodlines, it also resulted in many breed-specific diseases. For example, Labrador retrievers and German Shepherds are prone to hip dysplasia (inadequate fit of the joint that leads to serious mobility issues over time), golden retrievers are prone to certain types of cancer, and jack terriers are susceptible to blindness.
Generating high-quality genomes for dingoes and wolves can help us determine the cause of these diseases, serving as a disease-free baseline or reference. These findings could lead to new targeted treatment options for purebred dogs.
This article was originally published on The conversation by Matt A. Field at James Cook University and J. William O. Ballard at La Trobe University. Read the original article here.