Balancing Breed Identity and Genetic Health


The fascinating world of canine breeds is as diverse as it is complex. Each breed, distinct in its ancestry, purpose, and typology, carries a unique identity woven together by these three threads. However, the challenges of maintaining breed purity and breed-specific traits often push these breeds into a narrow genetic corner, leading to potential health problems and a decrease in overall genetic diversity. This entry discusses the formation of new canine breeds, the role of DNA research and population genetics in promoting healthier breeds, and the importance of considering genetic diversity alongside breed characteristics in contemporary breeding practices. By examining the current practices and potential improvements in dog breeding, we aim to highlight the importance of balance and moderation in creating and maintaining healthy, robust canine breeds for future generations.

What is a dog breed?

A canine breed refers to a specific variety of domestic dog that has been selectively bred by humans to emphasize certain physical traits, behaviors, or skills. The breed’s characteristics are maintained through controlled breeding practices, resulting in a consistent set of traits passed on from generation to generation.

Canine breeds are distinguished by a variety of characteristics that have been selectively bred over generations. These characteristics can broadly be divided into physical traits, temperament traits, and breed-specific abilities or predispositions. Here are some examples:

Physical Traits: These are the most readily apparent differences between breeds and include things like size, type of coat (short, long, curly, straight, rough, smooth, etc.), ear shape (drop, prick, button, etc.), tail shape (curled, straight, docked, etc.), and general body shape and proportion.

Temperament Traits: Different breeds have different typical temperaments, which is why some breeds are known as good working dogs, some are known as good guard dogs, and others may be known for their independent streak. For example, Border Collies are typically energetic and intelligent, Basset Hounds are known for being laid-back and even a bit lazy, and Shiba Inus are often independent and reserved.

In addition to physical traits and temperament, canine breeds are indeed distinguished by ancestry, purpose, and typology. Let’s delve into these aspects:

Ancestry: Every dog breed has its own unique lineage. Some breeds have ancient origins and can be traced back thousands of years, while others are relatively modern and have been developed in the last couple of centuries. The ancestry of a breed can often tell us a lot about its traits and characteristics, as these are often closely tied to the environments and roles for which the breed was originally developed.

Purpose: Many breeds were developed for specific purposes related to work, hunting, or companionship. For instance, retrievers (like the Labrador Retriever) were bred to retrieve game for hunters, terriers (like the Airedale Terrier) were bred to hunt and dig for small game, and herding dogs (like the Border Collie) were bred to herd livestock. Some breeds, such as the Bichon Frise, were developed primarily for companionship. The original purpose of a breed can have a significant impact on its behavior, temperament, and physical characteristics.

Typology: This refers to the classification of dog breeds into various categories or types based on their shared traits or characteristics. For example, the American Kennel Club (AKC) groups breeds into seven categories: Sporting, Hound, Working, Terrier, Toy, Non-Sporting, and Herding. Each of these groups is characterized by a general type of work the dogs were bred for, or by certain traits they have in common. Sporting dogs are typically active and alert, Hound dogs have strong instincts to chase and track, Working dogs are bred for a variety of tasks including guarding or rescue work, and so on.

These factors – ancestry, purpose, and typology – together with physical and behavioral traits, all contribute to the rich diversity of canine breeds we see today (Bragg, 1996). The balance between ancestry, purpose, and typology is a crucial one, and an imbalance or a singular focus on any one aspect can lead to issues that range from health problems in the breed to a loss of the original breed characteristics and functionalities.

Overemphasis on Ancestry: If breeders focus too rigidly on maintaining pure bloodlines without considering the health, behavior, and functionality of the dogs, it can lead to inbreeding and associated health problems. This is unfortunately a common issue in some breeds, where certain diseases or health conditions have become widespread due to a lack of genetic diversity.

Neglect of Purpose: If the original purpose of the breed isn’t considered, it can result in dogs with physical and temperamental traits that are ill-suited to their lifestyle. For instance, highly active breeds like Border Collies or Australian Shepherds can become frustrated and develop behavioral issues if they don’t have enough exercise and mental stimulation, which is a part of their original purpose – herding.

Exaggeration of Typology: If breeders focus too heavily on certain physical characteristics to the exclusion of all else, it can lead to exaggerated traits that can cause health problems for the dogs. A classic example is the brachycephalic (short-nosed) breeds like Bulldogs and Pugs, where the desire for an increasingly flat face has led to widespread breathing problems in these breeds.

A more holistic approach to breeding, which takes into account the health, behavior, original purpose, and physical characteristics of the breed, could help address many of these issues. Education and awareness among breeders and prospective dog owners are key to driving changes in breeding practices and improving the health and welfare of dogs.

The Genesis of Dog Breeds

The development of canine breeds is often complex and multifaceted, with many breeds having roots that are difficult to trace due to the lack of detailed records. While some breeds are relatively recent with well-documented histories, others have existed for centuries or even millennia, and their origins can be quite murky.

Here are a few ways that breeds may come into existence:

Natural Selection: Some breeds may have developed largely through natural selection, with certain traits becoming prevalent because they were advantageous in a particular environment. This is likely how some of the ancient breeds, such as the Afghan Hound or the Basenji, came into existence.

Selective Breeding for Specific Roles: Many breeds were deliberately created by humans selecting and breeding dogs that were particularly good at certain tasks, such as herding, hunting, or guarding. Over time, these dogs became distinct breeds.

Mixing Existing Breeds: Some breeds are created by deliberately mixing two or more existing breeds to combine certain desirable traits. This is how many of the newer “designer” breeds, like the Labradoodle (Labrador Retriever + Poodle) or the Cockapoo (Cocker Spaniel + Poodle), have been developed.

Spontaneous Genetic Variation: Occasionally, a new breed might develop because of a spontaneous genetic mutation that creates a unique trait. If humans find this trait desirable, they might breed dogs with this mutation to create more dogs like it.

Tracing the origins of a breed can often provide interesting insights into the history of human societies, as dogs have been closely tied to human activity for thousands of years. However, the exact origins of many breeds will likely remain a mystery, obscured by the passage of time and the lack of written records.

In the genetic establishment of a new breed, there are typically four key factors at play: the initial founding event, a period of isolation, a degree of inbreeding, and the application of artificial selection (Bragg, 1996).

Founder Event: This is when a new population (in this case, a new breed) is established by a small number of individuals (the ‘founders’). These founders will contribute all the genetic diversity for the new breed, which can be quite limited especially if only a few dogs are involved.

Isolation: For a breed to maintain its unique characteristics, it generally needs to be genetically isolated from other breeds. This means that dogs from this breed are primarily bred with other dogs from the same breed, limiting the inflow of new genetic material. This isolation can be geographic (if a breed is developed in a remote location) or it can be enforced by breeders (who only breed dogs from the same breed together).

Inbreeding: Inbreeding often occurs in the development of a new breed, especially if the number of founder dogs is small. While inbreeding can help to solidify the breed’s characteristics and make them more consistent, it can also lead to the proliferation of harmful genetic traits and reduce the breed’s overall genetic diversity, which can make them more susceptible to various health problems.

Artificial Selection: This is the process of humans selecting which dogs to breed based on specific traits that they wish to propagate. Over time, this selective breeding can lead to significant changes in the breed’s characteristics. Breeders might select for a variety of traits, including physical characteristics (e.g. size, structure), behavioral traits (e.g. herding instinct, aggressiveness), or health (e.g. disease resistance).

These processes work together to shape the genetic makeup of a breed, and they are the primary tools that humans have used to create the incredible diversity of dog breeds that we see today. However, it’s worth noting that these processes can also contribute to certain health and welfare issues in dogs, so responsible breeding practices are important to ensure the long-term health of the breed.

Maintaining Health and Vitality

While the initial processes of founding events, isolation, inbreeding, and artificial selection can be instrumental in establishing a new breed, these same practices can potentially be harmful if continued without moderation in the long term.

For example, while a degree of inbreeding can help establish breed consistency initially, continued inbreeding can lead to a decrease in genetic diversity, potentially making the breed more susceptible to various genetic disorders and diseases. Similarly, while isolation can help maintain breed purity, it can also restrict the gene pool, causing similar issues.

Artificial selection, when focused too heavily on specific traits—like appearance—may inadvertently sideline important aspects such as health and temperament. This could lead to breeds with health issues or behavioral problems.

Therefore, it’s essential that breeders focus on the overall health and well-being of the breed, which often involves introducing new genetic diversity to avoid the issues associated with inbreeding, as well as balancing the selection for physical traits with selection for health and temperament traits.

In essence, while these practices are essential in the formation of a new breed, their application must evolve as the breed matures to ensure its continued health and viability in the long term.

The Misconception of Purebredness

The concept of breed purity in the world of purebred dogs has led to the widely held perception that purebred, registered dogs are of higher quality compared to mixed breeds or unregistered dogs. This perception is often fueled by the belief that purebreds possess predictable traits and characteristics, conform to established breed standards, and carry a certain prestige due to their documented lineage.

However, it’s essential to remember that “quality” in a dog is not determined solely by breed purity or registration status. While purebred dogs have characteristics that can be predicted to a certain extent, they can also carry a higher risk for certain genetic health issues due to the restricted gene pool and practices of inbreeding in some breeds.

On the other hand, mixed-breed dogs can often have lower incidences of certain breed-specific genetic disorders and can possess a combination of desirable traits from multiple breeds. However, their traits might be less predictable, particularly if their lineage is unknown.

The concept of quality should ideally encompass a dog’s overall health, temperament, and suitability for a particular lifestyle or purpose, rather than just breed purity or registration status. A responsible approach to dog breeding and ownership should prioritize health, temperament, and welfare above all else.

Population geneticists argue that small, closed populations subject to intense artificial selection and high levels of inbreeding (often referred to as “incest breeding” in animal breeding) can suffer a decline in genetic health and vitality over the long term without periodic outcrossing, which is the introduction of new, unrelated genetic material.

In the context of dog breeding, “outcrossing” refers to the practice of breeding dogs from separate, unrelated lines. This is distinct from merely bringing in a dog from another breeder or kennel if that dog is derived from the same foundational bloodlines. Genuine outcrossing introduces new genetic material into the breed, increasing genetic diversity and reducing the risk of harmful recessive traits becoming widespread.

The goal of outcrossing is to balance maintaining the unique traits of the breed with ensuring sufficient genetic diversity to promote health and vitality. It’s a strategy that needs careful management, because while it can help to mitigate health issues associated with inbreeding, it may also introduce new traits that could change the breed’s characteristics. Therefore, it requires thoughtful and responsible breeding practices to ensure the long-term welfare of the breed.

Beyond the Typological Mindset

Advances in DNA research have transformed our understanding of species, subspecies, and varieties in zoology, offering insights into the complex interplay of genetics and evolution. This same understanding could certainly be applied to dog breeding to promote healthier, more genetically diverse populations.

In essence, Bragg (1996) suggests a shift from a focus on maintaining the “type” (or physical characteristics and traits) of a breed, which can lead to overemphasis on certain traits and inbreeding, towards thinking of breeds as populations. This “population thinking” approach would focus on maintaining a healthy level of genetic diversity (heterozygosity) within a breed, similar to what we see in healthy wild animal species.

In practical terms, this might involve strategies like outcrossing (breeding dogs from different lines), limiting the use of popular sires (to avoid too many dogs in the population being closely related), and considering genetic health along with physical traits when choosing which dogs to breed.

Of course, this doesn’t mean that breed characteristics would be ignored, but rather that they would be considered alongside the goal of maintaining genetic diversity and health. This could indeed result in healthier dog breeds, although it would likely require significant changes in breeding practices and potentially in breed standards as well. It would also require education and collaboration among breeders, breed clubs, and kennel clubs to promote this more balanced approach to dog breeding.

Outcrossing & Assortative Breeding

For small, highly inbred populations where there’s no larger population of similar dogs to draw from, outcrossing to a similar breed can be a useful strategy to reduce inbreeding depression and increase genetic diversity. However, it’s essential that this is done thoughtfully and strategically, as not all outcrosses will necessarily be beneficial for the breed.

In selecting a breed for outcrossing, breeders need to consider a variety of factors. These might include the similarity of the breed in terms of physical traits, temperament, and original function, as well as the health profile of the breed. The goal is to introduce new genetic diversity while still maintaining the key characteristics of the breed.

Additionally, breeders need to monitor the results of the outcross carefully over multiple generations. Outcrossing can introduce new traits and potentially new health issues, so it’s essential to track these changes and adjust breeding practices as needed.

Assortative breeding, also known as selective breeding, is a type of breeding in which animals with specific traits are chosen to breed together in an effort to produce offspring that have these desirable traits. It is a key process in animal husbandry and has been used for thousands of years to enhance desired characteristics in domestic animals, including dogs.

There are two types of assortative breeding:

Positive Assortative Breeding (or Direct Assortative Breeding): This involves mating animals that are similar in key traits in order to produce offspring that also exhibit these traits. For example, if breeders want to produce dogs that are particularly good at herding, they might choose to breed two dogs that both exhibit strong herding instincts.

Negative Assortative Breeding (or Disassortative Breeding): This involves mating animals that are dissimilar in certain traits. This method can increase genetic diversity, which can be beneficial for the overall health and resilience of the population. It can also be used to balance out extreme traits or to avoid the propagation of harmful traits.

In the context of dog breeding, assortative breeding is used to produce dogs that meet specific breed standards. However, it’s important to remember that while this can enhance desired traits, it can also lead to a reduction in genetic diversity and can increase the risk of certain genetic health issues if not managed carefully. As such, responsible breeding practices should also take into account the overall health and genetic diversity of the breed, alongside the desire to enhance specific traits.


This entry revolved around the topic of canine breeds, their formation, maintenance, and potential genetic issues arising from certain breeding practices.

It began with an exploration of the factors distinguishing canine breeds, namely their ancestry, purpose, and typology. These factors are intrinsically linked, and a balanced interrelation between them is essential for the full identity of a breed. Yet, this balance is often missing in modern dog breeding practices, with ancestry being overemphasized and purpose/utility being overlooked.

The conversation then delved into how canine breeds originate, highlighting four key processes: a founder event, isolation, inbreeding, and artificial selection. It’s crucial to note that while these practices are necessary for the establishment of a new breed, continued use without moderation can be detrimental in the long run, potentially leading to decreased genetic diversity and associated health issues.

DNA research and a deeper understanding of population genetics can offer solutions. Moving from a typological view (focusing on the breed’s physical traits) to a population-based view (considering genetic diversity within the breed) can help maintain healthier, more genetically diverse populations. This might involve strategies like outcrossing and limiting the use of popular sires.

However, any outcrossing must be done thoughtfully, considering the breed used for outcrossing, the results over multiple generations, and the overall health and well-being of the dogs. The concept of assortative breeding, in which animals with similar or dissimilar traits are selectively bred, also plays a significant role in this process.

While maintaining breed characteristics is important, it shouldn’t compromise a breed’s overall genetic health and vitality. Balancing these considerations is a key aspect of responsible breeding practices.


This article presents a contemporary amalgamation of J. Jeffrey Bragg’s essays, including his 1996 piece, “Purebred Dog Breeds into the Twenty-First Century: Achieving Genetic Health for Our Dogs.” While Mr. Bragg’s original works hold educational significance, they include personal anecdotes and frequently contain biased perspectives. Here, I have endeavored to condense his ideas into a concise and informative piece using my own language.

  1. J. Jeffrey Bragg, ” Purebred Dog Breeds into the Twenty-First Century: Achieving Genetic Health for Our Dogs,” Accessed May 18, 2023,
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Tony Bierman, "Balancing Breed Identity and Genetic Health," OBTESA, Accessed June 18, 2024,