The Dog Genome Project

Understanding The Dog Genome Project

With 100s of dog breeds in the world, there's a dog for every type of person. But do you know how those breeds came to be, how their traits differ, which ones are really closely related, what makes some dogs more vulnerable to certain diseases and how they can help understand corresponding human diseases? Well, the scientists at The University of Oregon, and the Fred Hutchinson Cancer Research Center once took an initiative to determine the same through its research project named “The Dog Genome Project.” The project today is a part of the National Human Genome Research Institute at the National Institute of Health in Bethesda, Maryland.

The Objective of the Dog Genome Project

Launched in 1990 as a $50 million project under the leadership of Dr. Elaine Ostrander, Ph.D., the project’s initial goal was to map the canine genetics and genomics in order to characterize disease genes and the genes controlling behavior and morphology.

The research is based on the fact that genes hold the key to all inherited information. The genes line up on chromosomes like beads on a string, and their pattern can be mapped, improving scientist’s understanding of how genetic traits are passed from parent to offspring.  

Since dogs are a close evolutionary relation to humans, the comparison of both can help reveal important information about the structure and evolution of genes and genomes.  Dog genomes can help understand natural variation in dog populations, like body size or fur type, and for getting more information about how the genomes of both dogs and humans contribute to health and disease.

Because human breeding is largely random, it is more difficult to isolate a disease-causing gene. Purebred dogs, on the other hand, trace their lineage back several generations through the process of selective inbreeding. They have been bred for their good characteristics, and the weaker characteristics have been bred out over decades.

There are 190 dog breeds recognized by the American Kennel Club (AKC). This diversity of breeds makes it possible for geneticists to more easily identify the specific genes that cause a disease.

Dog genetics can also help the scientists understand the genetic basis of both mammalian development and behavior.

As mentioned on the NHGRI’s official website, the present objective of the institute is to understand how genes interact to create the modern dog breeds and to find DNA variants that are associated with several diseases. This will help them reduce the occurrence of diseases in affected breeds. Since many diseases in dogs are quite similar to disorders in humans such as diabetes, epilepsy and cancer, these findings will hopefully provide valuable insights and new avenues of research for human health as well.

The Canine Genome Sequencing Project

This genome sequencing project was led by the Broad Institute/MIT Center for Genome Research in association with The National Human Genome Research Institute (NHGRI). Purebred dog, the Boxer, was chosen as the breed to carry out the research. Boxers were specifically chosen because they have the least variation in their genome. By comparing Tasha with other dog breeds and humans, scientists were able to uncover the exciting connection between them. The study revealed that humans and dogs share 18,473 common genes.  The scientists were also able to uncover some other mysteries related to human genes, their evolution, and the regulatory mechanisms governing their expression. The study has also shown that by understanding the patterns of variation in different dog breeds, scientists can design effective and powerful gene mapping experiments for complex diseases that are otherwise difficult to map in humans.

The First Family Tree of Dogs

In 2017, researchers from the Dog Genome Project at the National Institutes of Health released the most detailed canine family tree to date, revealing the hidden history of man’s best friend. The tree which contains more than 160 dog breeds creates a timeline of when, how and from where these dogs emerged. The resulting data was compiled by the researchers by sequencing and comparing the genomes of 1,346 individual dogs over 20 years.

Almost all the dog breeds fell into 23 larger groupings called clades. Although genetically defined, the clades also tended to group together dogs with similar characteristics or traits: Thus bulldogs, boxers, and Boston terriers—all bred for strength—fall into one clade; whereas herders like corgis, sheepdogs, and collies fall into another.

According to the results, herding dogs such as corgis, sheepdogs, and collies were bred independently in various parts of Europe with lineages tracing to the United Kingdom, northern Europe and southern Europe.  Another finding has revealed that some breeds from Central and South America like the Xoloitzcuintle and the Peruvian Hairless Dog probably descended from canines that crossed the Bering land bridge with humans thousands of years ago.

The study also suggests there were likely two intensive periods of dog breed diversification. The first occurred during hunter-gatherer times when dogs were bred for their skills. The second took place when dogs were bred more often for their looks. This period, also known as the "Victorian Explosion", marks the emergence of most modern dog breeds. This study will also help researchers get an idea about which genes and mutations are associated with human diseases.

However, the canine family tree is still incomplete. The team has sequenced less than half of around 400 recognized dog breeds in the world, and this means, there are several missing branches that are yet to be filled.

The scientists at the National Human Genome Research Institute are actively working on Dog Genome Project and there is yet to see a lot of accomplishments in the coming years. Hopefully, the research, one day, will be able to completely understand the genesis of our closest friends and find cures for diseases that are plaguing both humans and dogs.