Selective breeding has shaped many of today’s most recognisable dog breeds, helping preserve appearance, temperament, and working traits.
However, breeding within narrow gene pools over long periods can reduce genetic diversity, increasing the likelihood of inherited health conditions and limiting long-term resilience.
Researchers and veterinary organisations continue to study how population size, breeding practices, and historical bottlenecks influence genetic health across different breeds.
Understanding these challenges helps owners, breeders, and welfare groups make more informed decisions about responsible breeding, health screening, and long-term sustainability.
While many dogs live healthy, happy lives, awareness of genetic diversity supports better planning for future generations and encourages ethical breeding practices that prioritise wellbeing over appearance alone.
This article is for general knowledge only and is based on information gathered from online sources.
Individual dogs may vary depending on breed lines, health screening, care, and environment.
For personalised advice or breeding-related concerns, consult a qualified veterinarian or accredited canine genetics specialist.
Photos are for illustrative purposes only.
1. Labrador Retrievers
Labs are among the most popular family dogs in North America, but they carry a hidden genetic threat.
Research shows that roughly 30 to 40 percent of Labrador Retrievers are carriers of a mutation in the DNM1 gene, with 3 to 13 percent actually affected by exercise-induced collapse.
This condition causes dogs to experience sudden weakness and collapse after intense physical activity.
The mutation disrupts normal nerve function during exercise, which can be frightening for both dogs and their owners.
Dogs with two copies of the mutated gene will show symptoms, while carriers with just one copy appear healthy but can pass the problem to their puppies.
Genetic testing before breeding could help reduce this disorder in future generations.
2. Chesapeake Bay Retrievers
This rugged water dog from Maryland’s shores faces the same genetic challenge as its Labrador cousins.
Chesapeake Bay Retrievers have been identified as carriers of the DNM1 mutation that causes exercise-induced collapse.
These dogs were originally bred to retrieve waterfowl in icy conditions, so their inability to handle intense activity threatens their working purpose.
The breed’s relatively small population makes this genetic issue even more concerning.
When a rare breed carries a harmful mutation, it becomes harder to breed it out without further reducing genetic diversity.
Responsible breeders now have access to DNA tests that can identify carriers.
Making informed breeding choices could preserve both the breed’s health and its remarkable swimming abilities.
3. Curly-Coated Retrievers
With their unique tight curls and elegant appearance, Curly-Coated Retrievers stand out among sporting dogs.
Unfortunately, they also carry the problematic DNM1 mutation linked to exercise-induced collapse.
This breed already has limited genetic diversity due to its small global population, which makes any genetic disorder more threatening.
When a breed has few individuals, harmful genes can spread quickly through the population.
Curly-Coated Retrievers need careful genetic management to avoid both the collapse disorder and other health problems related to inbreeding.
Testing breeding dogs helps identify carriers before they reproduce.
This proactive approach may help maintain the breed’s health while preserving its distinctive characteristics and working abilities for years to come.
4. Boykin Spaniels
South Carolina’s state dog carries more than just regional pride.
Boykin Spaniels have been confirmed as another breed susceptible to the DNM1 mutation that causes exercise-induced collapse.
These enthusiastic hunting dogs were developed to retrieve game from swamps and lakes, so their genetic vulnerability to collapse during activity is particularly troubling.
The breed’s friendly personality and moderate size make them popular family pets beyond their hunting roots.
However, potential owners should know about this genetic concern.
Breeders who test their dogs and avoid pairing two carriers can significantly reduce the risk.
Since the disorder is autosomal recessive, puppies need two mutated genes to develop symptoms, giving responsible breeders clear guidance for healthy breeding programs.
5. Pembroke Welsh Corgis
Those adorable short legs and big ears hide a genetic surprise.
Pembroke Welsh Corgis have been found to carry the DNM1 mutation, which was unexpected since they are not traditional retrievers or hunting dogs.
This discovery shows that the genetic problem has spread beyond the breeds where it was first identified.
Corgis are energetic herding dogs despite their compact size, often running and playing with great enthusiasm.
Exercise-induced collapse could seriously impact their quality of life and ability to do the farm work they were bred for.
The mutation’s presence in this breed highlights how genetic disorders can appear in unexpected places.
DNA testing becomes even more important when a problem shows up where breeders might not expect it.
6. Old English Sheepdogs
Behind all that shaggy fur lies a genetic concern that might surprise many dog lovers.
Old English Sheepdogs have been identified as carriers of the DNM1 mutation, joining the list of breeds affected by exercise-induced collapse.
These large, playful dogs are known for their boundless energy and clownish behaviour, making collapse during activity especially worrying.
The breed’s thick coat already requires significant grooming commitment, and adding genetic health concerns makes responsible breeding even more critical.
Since Old English Sheepdogs are not as common as Labradors, maintaining genetic health in a smaller population requires extra attention.
Breeders can use available genetic tests to identify carriers and make smart pairing decisions that protect future generations.
7. American Cocker Spaniels
These sweet-faced companions with their silky ears carry the same genetic mutation affecting larger sporting breeds.
American Cocker Spaniels have been confirmed to carry the DNM1 gene mutation, which was somewhat unexpected given their primary role as companion animals rather than intense working dogs.
Their smaller size does not protect them from this hereditary neuromuscular disorder.
Cocker Spaniels already face other breed-specific health challenges, making this additional genetic concern more serious.
The autosomal recessive nature of the disorder means careful breeding choices can prevent affected puppies.
When both parents are tested and breeding pairs are chosen wisely, the risk drops dramatically.
This breed’s popularity means many dogs could benefit from increased awareness about genetic testing among breeders and puppy buyers.
8. Bouvier Des Flandres
This powerful Belgian farm dog represents how widespread the genetic issue has become.
Bouvier des Flandres, a breed quite different from typical retrievers, has also been found carrying the DNM1 mutation.
These rugged working dogs were originally used for herding cattle and pulling carts, so their genetic vulnerability to exercise-induced collapse is particularly concerning.
The presence of this mutation across such varied breeds suggests it may be more ancient than researchers initially thought.
Bouviers are already a less common breed, which makes genetic management crucial for their survival.
Testing programs and careful record keeping can help breeders avoid producing affected puppies.
The situation demonstrates why genetic research and responsible breeding practices matter for all dog breeds, not just the most popular ones.
