Introduction
For centuries, humans have purposely bred dogs to create distinct breeds with desired traits and behaviors. Today, there are hundreds of recognized dog breeds around the world, each with characteristic appearances, personalities, and purposes. Knowing the breed of a dog offers valuable insight into what to expect from that dog in terms of size, shedding, exercise needs, health issues, trainability, and more.
Additionally, identifying a mixed-breed dog’s genetic heritage can reveal key personality traits, behavioral tendencies, and health predispositions they may have inherited. With the advent of DNA testing for dogs, breed identification has become increasingly accurate. DNA tests can provide owners, shelters, and rescue groups with useful information to better care for, train, socialize, and match dogs with the right owners.
How Dog Breeds Originated
The origins of modern dog breeds trace back thousands of years to the domestication of wolves. As early humans began to settle and develop agriculture, wolves likely started scavenging around human camps for food scraps. Over many generations, certain wolves became tolerant of humans and were able to be domesticated.
Selective breeding of dogs then began, originally for purposes like hunting, herding, and guarding. Distinct dog breeds started emerging around 10,000 years ago. As human civilization advanced, dog breeds continued to be refined for various roles and physical traits.
In the mid-19th century, dog shows became popular. Breed standards were created for conformation showing, further exaggerating physical and behavioral differences between breeds. Many modern dog breeds resulted from meticulous fine-tuning over the last 200 years.
Today, the behaviors, sizes, shapes, colors, coats, and other attributes of dog breeds showcase the results of both ancient and modern selective breeding. Genetic analyses reveal deep divergences between breeds that originated hundreds or thousands of years ago.
DNA and Genetics
All dogs have DNA that provides the genetic blueprint for their physical characteristics and traits. DNA is made up of four chemical bases – adenine (A), thymine (T), cytosine (C) and guanine (G) – that pair up in sequences called base pairs. The unique order of these base pairs is what determines the genetic code.
Genes are specific sequences of base pairs that code for particular proteins. For example, some genes contain instructions for eye color, coat color, muscle composition, and much more. The entirety of an organism’s genetic information is known as its genome.
Each dog inherits half its genome from the mother and half from the father. This combination of maternal and paternal DNA is what makes each dog unique. Even dogs of the same breed can have small differences in their genetic code.
During reproduction, the process of genetic recombination shuffled the base pairs into new combinations for offspring. This adds to the diversity within dog breeds and species as a whole. Environmental factors then influence how the genetic code is expressed in each dog.
Dog Breed Identification Tests
In recent years, commercial dog DNA tests have become widely available to pet owners and shelter workers. These tests analyze a dog’s genetic markers to predict its breed composition and ancestry. Some of the most popular dog DNA tests include:
- Wisdom Panel – Screens for over 350 breeds, types, and varieties. The company also offers specialized genetic health screening.
- Embark – Tests over 350 breeds and 200,000 genetic markers. Provides a family tree analysis.
- DNA My Dog – Tests for over 100 breeds. Offers the lowest cost tests.
- Find My Pet DNA – Tests for over 90 breeds. Allows you to store pets’ DNA for identification.
Most dog DNA tests involve obtaining a simple cheek swab sample from the dog which is then analyzed at the company’s lab. Test kits are mailed directly to the dog owner. Results are typically available within 2-3 weeks and provide breed ancestry percentages and family history tracing back several generations in a dog’s lineage. Some tests also screen for genetic diseases.
Accuracy of Breed Tests
Breed identification DNA tests have become increasingly popular among dog owners curious about the breeds in their dog’s genetic makeup. However, research shows these tests may not always provide accurate results.
In one study published in the journal Animal Genetics, researchers tested over 900 dogs from 88 breeds using a common dog DNA test. They found that for purebred dogs, the tests were highly accurate at identifying the main breed. However, for mixed-breed dogs, the results were less reliable. The test only correctly identified a dominant breed about 27% of the time.
One reason is that these tests compare DNA to a limited breed signature database. Many breeds are very genetically similar or have been recently crossed. Tests also cannot always distinguish low levels of DNA from purebred ancestors many generations back in a dog’s lineage. The number of breeds identified in mixed dogs is also often inaccurate.
While DNA tests can provide some useful breed information, owners should understand their limitations. Visual identification and documentation of a dog’s parents may be more reliable for determining breed makeup. More research is still needed to improve test accuracy for mixed-breed dogs.
Limitations of Breed Identification Tests
While DNA tests can provide useful breed information, they also have some important limitations to consider:
Accuracy for mixed breed dogs: Most tests struggle to identify complex genetic mixes, especially beyond 3-4 generations of mixing. The more breeds in a dog’s ancestry, the less accurate the breed prediction.
Inability to detect some ancestry: Tests can only detect breeds with distinct genetic markers in their database. Rare breeds or village dogs may not be detected if not in the database.
No prediction of visual traits: DNA doesn’t indicate specific physical traits like size, shape, coat color. Visual identification is still needed along with DNA tests.
Possibility of surprise ancestry: Tests sometimes reveal unexpected breeds. Owners may be surprised a dog is not the exact breed mix they assumed.
No behavior predictions: Despite some genetic predispositions, DNA cannot reliably predict real-world behavior and temperament. Environment plays a major role too.
Commercial business model: DNA testing is a profitable business, so some companies may exaggerate marketing claims or encourage excessive testing.
Other Traits Revealed by Tests
In addition to breed identification, dog DNA tests can reveal interesting information about a dog’s traits beyond its breed makeup. Here are some of the other insights genetic testing provides:
Health conditions and disease risk: DNA tests screen for genes linked to hundreds of inherited diseases like progressive retinal atrophy, degenerative myelopathy, and dilated cardiomyopathy. They can indicate if a dog is at risk for developing certain conditions.
Drug sensitivity: Tests can determine how a dog may respond to certain medications based on their genetic markers.
Physical traits: DNA can reveal genetic predispositions for traits like coat color, shedding amount, ear type, body size, and muscle composition.
Behavior and temperament: Tests provide insight into behavioral tendencies like trainability, playfulness, aggression, excitability, and more by analyzing key genetic markers.
While not completely predictive, these additional findings from breed tests help create a fuller picture of a dog beyond just its breed makeup. This information empowers owners to better understand their dog’s health, training, and care needs.
Uses of Breed Information
Knowing the breed composition of a dog can be useful for owners, veterinarians, and animal shelters in several ways:
For dog owners, breed information can help guide decisions about care, training, exercise needs, and potential health issues to watch out for. Certain breeds are prone to specific conditions, like hip dysplasia in larger dogs or eye diseases in bulldogs. Veterinarians may tailor preventative care or diagnostic testing based on a dog’s likely breed mix.
Shelters and rescues can use breed tests to better match dogs with adopters. Breed tendencies toward behavior, size, and energy level help ensure a good fit. Tests also aid efforts to identify lost dogs. Some apartment buildings or homeowner associations restrict certain breeds, so testing helps avoid adoption returns.
Breed analysis provides veterinarians insight into possible inherited diseases to diagnose and treat. It also assists research into breed-specific illnesses and new therapies. Pharmaceutical companies can use breed data to develop medications tailored to dogs of different genetic backgrounds.
Law enforcement and forensic scientists might use breed tests on stray dogs or dog attack cases when trying to identify a canine culprit based on witness descriptions of its breed. However, lack of test accuracy makes this application controversial.
Responsible use of breed analysis provides benefits in many situations. However, ethical questions remain about breed stereotyping or discrimination. Overall, a dog’s individual behavior and personality, not just its breed, determines how it interacts with humans.
Ethical Considerations
One of the biggest ethical concerns surrounding dog breed DNA tests is the risk of breed stereotyping. Just because a dog has the genetic markers of a certain breed does not mean they will exhibit all the traits typically associated with that breed. Breed stereotypes can lead to false assumptions about a dog’s temperament, energy level, size, etc. Shelters or rescues may pre-judge dogs based on their breed mix revealed by a DNA test, which could impact adoption rates for certain breeds. There is also the risk that people will make assumptions about mutts or mixed breed dogs that reinforce notions about so-called “superior” purebreds. Dog owners should keep in mind that environment and training play a huge role in any dog’s behavior – not just their genetic background. While breed tests provide interesting ancestry information, a dog should always be judged as an individual.
Conclusion
In summary, DNA tests can provide useful information about the likely breeds in a dog’s ancestry, but they have limitations. The tests look for genetic markers associated with different breeds to make an educated guess at a dog’s lineage. However, they do not provide definitive proof of breed, especially for mixed breeds. The more breeds in a dog’s background, the less accurate the tests tend to be. Furthermore, DNA cannot reveal some important traits like environmental influences and individual temperament. So while breed identification tests can be a fun way to get insight into a dog’s heritage, people should not place too much weight on their results. The tests provide clues, not definitive answers, about a complex genetic history. Other factors like wisdom from those familiar with the dog and observed behaviors over time also play a role in understanding “what breed” of dog an individual is in terms of personality and needs.