Many people know that modern dogs evolved from the gray wolf. But did you know that most of the more than 340 modern dog breeds we see today only emerged 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 associated with humans ever since.
The dingo – the only native Australian dog – is thought to represent a unique phenomenon within canine evolution, having arrived in Australia between 5,000–8,000 years ago.
Yet the exact place of the dingo in the evolutionary family tree of dogs has never been known.
To find out where they turned away from gray wolves on their evolutionary journey, we used state-of-the-art DNA sequencing techniques to discover that dingoes are fundamentally different from domestic dogs.
In research published on Friday science advanceIn collaboration with 25 researchers from four countries, we show that the dingo is an early offshoot of modern dogs that lie between the gray wolf and today’s domesticated dogs.
This work has potential implications for the health of all modern breed dogs.
dog and human history
By studying dogs we can gain insight into how we humans affect their physical and behavioral traits, as well as observe changes in their genomes.
For example, dogs have recently developed the ability to raise their eyebrows – a trait developed to communicate more effectively with humans. So it looks like puppy dog ​​eyes were really just “made” 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 require a special gene (amylase 2b) to digest starch. Many dog ​​breeds have multiple duplicates of this gene (sometimes more than ten copies). However, the wolf and the dingo carry only one copy of this gene.
This duplication in modern dogs probably resulted from a change in the diet of early domesticated dogs, as they were fed starchy foods such as rice (early cultivated through extensive agriculture).
Interestingly, similar gene duplications have recently occurred independently in domesticated animals, indicating how humans may influence the genome of domesticated animals.
early branch of modern dogs
Dingoes are unique because they have been geographically isolated from wolves and domestic dogs for thousands of years. In our study, we used genetics to help us understand where the dingo fits into the evolution of dogs, and what role it played in the Australian ecosystem.
Initially, in 2017, we only had access to the genome of one dog as a point of comparison (a Boxer breed). It had many gaps due to the limitations of technology at the time.
However, in the same year, Dingo won the “World’s Most Interesting Genome” competition organized by the US biotech company Pacific Biosciences. This got us thinking about making a high quality dingo genome.
But to understand the place of the dingo in dog history, we also needed several high-quality canine genomes. We therefore generated a German Shepherd genome as a representative breed, followed by the Basenji (the oldest dog breed used for hunting in the Congo).
In the end, we were able to sequence the genome of a purebred desert dingo puppy, Sandy, which was left on the outside.
The ability to generate high quality genomes has only become possible in the past few years, due to the development of long-read sequencing technology. This technology has also been instrumental in completing the recently announced complete human genome.
Using our new canine genome – along with existing genomes from the Greenland wolf and other representative species including the Great Dane, Boxer and Labrador – we have measured the number of genetic differences between these breeds and the dingo to show conclusively that Where does the dingo fit into the evolutionary timeline.
We found that the dingo is actually an early offshoot of all modern dog breeds between wolves and today’s domesticated dogs.
future work
Collectively, our analysis reveals how different demographic and environmental conditions have shaped the dingo genome.
We can’t say for sure whether the dingo has ever been domesticated, but we do know that it is unlikely to be domesticated once it arrived in Australia.
Future work on more dingo genomes will reveal whether dingoes have ever been domesticated, and also measure the level and impact of pure dingo crossbreeding with domestic dogs.
While many hybrid dingoes are similar in appearance, substantial crossbreeding has occurred, particularly in New South Wales and Victoria.
This knowledge is important. A better understanding of the impact of dingo cross-breeding with dogs may provide insight into the role of dingoes in the ecosystem, and therefore help with future conservation efforts.
In addition, 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 target new ways to improve their health and vitality. can help.
veterinary applications
Through artificial selection, humans have been crossbreeding dogs selectively for desirable traits and characteristics for hundreds of years.
While this has created the modern purebred lineage, it has also resulted in a number of breed-specific diseases. For example, Labradors and German shepherds are prone to hip dysplasia (improper joint fitting that leads to serious mobility issues over time), golden retrievers are prone to certain cancers, and jack terriers are more susceptible to blindness.
Creating high-quality genomes for dingoes and wolves can help us determine the cause of these diseases by serving as a disease-free baseline or reference. These discoveries could lead to new targeted treatment options for dogs of the breed.
Matt A. Field, Associate Professor – Bioinformatics, James Cook University and J. William O. Ballard, Professor and Head of the Department, Environment and Genetics, SABE, La Trobe University.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
