Many people we 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 emerged in the last 200 years?
Dogs were first domesticated during the Neolithic Age, between 29,000 and 14,000 years ago, and have been closely linked to humans ever since. Dingoes, Australia’s only native dog, are thought to represent a unique event in canine evolution, having arrived in Australia between 5,000 and 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 diverged from gray wolves in their evolutionary journey, we used cutting-edge DNA sequencing technologies to discover that dingoes are fundamentally different from domestic dogs.
In research published in Progress of science, in collaboration with 25 researchers from four countries, we show that dingoes are an early branch of modern dogs situated between the gray wolf and today’s domesticated dogs. This work has potential implications for the health of all modern dog breeds.
History of the dog and humanity
By studying dogs, we can gain insight into how we as humans have influenced their physical and behavioral traits, as well as observe changes in their genome.
For example, dogs recently developed the ability to raise their eyebrows, a trait that likely evolved to communicate more effectively with humans. So it looks like puppy dog eyes really were “created” just for us.
But some examples are not so obvious and can only be found by digging deeper into dog genomes.
For example, previous scientific studies have shown that dogs need a particular gene (amylase 2B) to digest starch. Many breeds of dogs carry several duplicates of this gene, sometimes more than 10 copies. However, the wolf and the dingo only retain a single copy of this gene.
This doubling in modern dogs was likely due to a change in the diet of early domesticated dogs, as they were increasingly fed starchy foods such as rice (cultivated through early widespread agriculture).
Interestingly, the same gene duplication has occurred independently in other recently domesticated livestock animals, indicating how humans may affect the genomes of domesticated animals.
Are dingoes an early offshoot of modern dogs?
Dingoes 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 dog evolution and what role it has in the Australian ecosystem.
Initially, in 2017, we only had access to a single dog genome for comparison (a boxer breed). It contained many loopholes, due to the limitations of technology at the time.
However, that same year, the dingo won the “World’s Most Interesting Genome” contest organized by the American biotech 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. So we generated a German Shepherd genome as a representative breed, followed by the Basenji (an early breed of dog, used for hunting in the Congo).
Finally, we were able to sequence the genome of a pure desert dingo pup, Sandy, that was found abandoned in the outback.
The ability to generate high-quality genomes has only become possible in recent years, due to the development of long-read sequencing technology. This technology has also been crucial to the recently announced completion of the entire human genome.
Using our new dog genomes, along with the existing genomes of 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 wolf fits. dingo in the evolutionary timeline.
We discovered that dingoes are really an early offshoot of all modern dog breeds, between the wolf and today’s domesticated dogs.
Future work – Taken together, our analysis shows how different demographic and environmental conditions have shaped the dingo genome. We can’t say for sure if the dingo has ever been domesticated, but we do know that it is unlikely to have been 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 crossbreeding with domestic dogs. While many hybrid dingoes are similar in appearance, there has been substantial interbreeding, particularly in New South Wales and Victoria.
This knowledge is important. A better understanding of the effect of dingoes interbreeding with dogs may provide insight into the role of dingoes in the ecosystem and thus help with future conservation efforts.
Additionally, knowledge about the evolutionary history of dingoes ultimately helps us understand how and when domestic dogs evolved alongside humans and may help us identify and find new ways to improve their health and vitality.
Veterinary Applications — Through artificial selection, humans have selectively bred dogs for desirable traits and characteristics for hundreds of years.
While this has created modern purebred bloodlines, it has also given rise to many breed-specific diseases. For example, Labrador retrievers and German shepherds are prone to hip dysplasia (a poor fit of the joints that leads to serious mobility problems over time), golden retrievers are prone to certain types of cancer, and jack terriers are susceptible. to blindness.
The generation of high-quality genomes for dingoes and wolves could help us determine the cause of these diseases by serving as a disease-free baseline or reference. These discoveries could lead to new breed-specific treatment options for 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.