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Collie

Collie
Photo: Yasu w / CC BY-SA 4.0 · Wikimedia

20 Collies in the atlas. Every number on this page has a source.

Population-genetic snapshot of Collies in the Sniff Atlas, source-graded Mendelian carrier frequencies from Donner 2023, and nutrition guidance tied to the genetic findings above.

See in the atlas → From CanVAS
The plain version

Collies come from a fairly close-knit gene pool, meaning they have some shared family traits. They’re known for their beautiful, long coats and smart, alert expressions. Some health issues linked to their genetics include eye conditions and sensitivity to certain medications, so it’s a good idea to talk with your vet or consider genetic testing to keep your collie happy and healthy.

What the atlas says about Collie

In the atlas, the Collie clusters consistently as Collie (100% of the 20 dogs here). At the trait loci, HMGA2 runs lower than average (0% here vs 56%); RSPO2 runs lower than average (9% here vs 55%). Dogs here sit in a relatively sparse region of the atlas, fewer close neighbors than typical.

Ranks 12 of 107 on the bottleneck severity scale, well into the upper quartile of population contraction. High breed predictability score (2.85), individual dogs of this breed reliably cluster together genetically. Only 20 dogs of this breed in the atlas, modestly sampled.

Genetic dimensions · CanVAS atlas

What the genome says about Collie

Computed from the 18,477 research dogs in the Atlas.

Dogs in the Atlas
20Founders
10 from Spatola, 10 from Hayward2016
Genetic diversity
0.24Tight
Mean heterozygosity across the breed. Ranks 12th most genetically tight of 107 ranked breeds.
What does genetic diversity mean?

How varied a breed's gene pool is — the share of gene spots where a typical dog of the breed carries two different versions rather than two identical ones.

How to read it: Higher = more diverse. Among well-sampled breeds it ranges roughly 0.22 (least diverse) to 0.33 (most diverse).

Diversity is a strength, not a verdict on any individual dog. Lower diversity means it's worth paying attention to recessive-risk testing — not that a dog is doomed.

Cluster structure
Single tight cluster
Intra-breed RMS distance: 24.54
What does within-breed variation mean?

How much individual dogs within the breed differ from each other genetically.

How to read it: Higher = more internal variety among individuals of the breed.

Sensitive to how many dogs of the breed we've sampled.

Related breeds
Gave rise to
In the Herding group
Explore the full lineage map →
VBO foundation stock (breeding records) · AKC breed group
Relatedness is documented lineage + kennel family. Genetic-ancestry distance measures diversity, not kinship, so it isn't used here.
How long they live
13.3years (life expectancy)
95% CI 13.3–13.6 · VetCompass, McMillan 2024, n=2,171. source
What does typical lifespan mean?

The median age dogs of the breed tend to reach.

How to read it: Higher = longer-lived. Compare to longevity-for-size to see whether it's just a size effect.

Drawn from population lifespan records; individual dogs vary widely with care, genetics, and luck.

Trait genetics
Allele frequencies at named morphology loci

Frequency of the alternate allele in this breed at each locus's representative SNP.

Body size
IGF195%
HMGA20%
SMAD2100%
LCORL100%
STC288%
ADAMTS1756%
Leg length
FGF4·CFA18100%
FGF4·CFA1295%
Coat
RSPO29%
FGF588%
KRT71100%
MC1R100%
Ear set
MSRB3100%
Skull shape
BMP382%
SMOC257%
n = 20 dogs · moderate confidence · CanVAS (Brundage 2026) · Sniff Atlas
Names & origins

Identified as Collie (VBO:0200375) in the Vertebrate Breed Ontology (Mullen et al. 2025, CC-BY 4.0) · registry IDs iDog 79 · VeNom 13879.

What you see when you look at a Collie

What does the genome say about how a Collie looks?

Collies look the way they do because of a small set of fixed and near-fixed morphology genes that, taken together, define the visible breed. Each translation below pairs the gene with the trait an owner actually sees, the breed's allele frequency at that locus, and a one-clause causal phrase.

Where the breed-defining genes act, mapped on a generic dog-body key — and how fixed each marker is in the Collie. The figure is the most-settled marker we read in that region; the full per-locus panel is below. (The silhouette is a shared anatomical guide, not this breed's outline.)

Body sizeSMAD2 · 100%Skull shapeBMP3 · 82%EarsMSRB3 · 100%Leg lengthFGF4 CFA18 · 100%Coat & colorKRT71 · 100%
CanVAS trait-locus panel (Brundage 2026)
15 morphology markers read across 5 regions. Allele frequency = how fixed a marker is in this breed, not whether your dog carries it.

Size and build

IGF1 is near-fixed at 95% for the small-body allele, which keeps the breed compact relative to its working-line ancestors.

IGF1what this gene does

IGF1 is a gene that plays a key role in determining a dog's body size. It influences how much a dog grows, affecting overall stature.

For your dog: Knowing about IGF1 gives you insight into your dog's size traits, but it’s just one part of the bigger picture when it comes to their health and care.

Full IGF1 gene page →

HMGA2 is at 0%, leaving most of the size signal to other loci in the panel.

HMGA2what this gene does

HMGA2 is a gene that influences body size in dogs, helping determine how big or small a dog grows.

For your dog: Knowing about HMGA2 helps you appreciate the genetic factors behind your dog's size, but it doesn't signal any health issues.

Full HMGA2 gene page →

SMAD2 is near-fixed at 100%, a chromosome-7 height locus differentiating small from giant breeds.

SMAD2what this gene does

SMAD2 is a gene involved in regulating body size by influencing how cells grow and develop.

For your dog: Knowing about SMAD2 helps understand your dog's size traits but isn't linked to health issues; no immediate action needed.

Full SMAD2 gene page →

LCORL is near-fixed at 100%, the NCAPG/LCORL height locus that is one of the strongest single contributors to canine body size.

LCORLwhat this gene does

LCORL is a gene that influences body size in dogs. It helps determine how big or small a dog might grow.

For your dog: Knowing about LCORL helps you appreciate the genetic factors behind your dog's size, but it’s just one piece of the bigger picture when it comes to health and care.

Full LCORL gene page →

STC2 is near-fixed at 88%, modulating growth-axis signaling toward the breed's body-size set point.

ADAMTS17 sits at 56%. ADAMTS17 is a body-size locus also linked to lens disorders.

ADAMTS17what this gene does

ADAMTS17 is a gene that influences body size and also plays a role in certain eye conditions. It affects the structure of tissues in the eye and elsewhere in the body.

For your dog: If your dog belongs to a breed known to carry ADAMTS17 variants, it’s worth discussing genetic testing and eye exams with your vet to stay ahead of potential issues.

Full ADAMTS17 gene page →

Leg length

The FGF4 retrogene on chromosome 18 is near-fixed in this breed at 100%. This is the leg-length variant. The breed is fully committed to the long-legged form rather than the short-legged Corgi-and-Dachshund body plan.

The FGF4 retrogene on chromosome 12 is near-fixed at 95%, the chondrodystrophic variant associated with intervertebral disc disease risk in breeds that carry it.

Coat type, length, and color

RSPO2 is at 9% for the furnishings allele. The breed does not carry the eyebrows-and-mustache pattern of Wheatens, Schnauzers, or wire-haired terriers.

RSPO2what this gene does

RSPO2 influences the texture and appearance of a dog's coat, particularly the presence of 'furnishings' like mustaches and eyebrows. It helps determine whether a dog has that distinctive wiry or textured look.

For your dog: If your dog has those wiry eyebrows or a mustache, RSPO2 is part of the reason—no health worries, just a coat feature worth knowing about.

Full RSPO2 gene page →

FGF5 is at 88% for the long-coat variant, which is why the breed's coat sits where it does on the long end of the dog coat-length spectrum.

FGF5what this gene does

FGF5 is a gene that influences the length of a dog's coat. It acts like a natural switch, telling hair follicles when to stop growing longer fur.

For your dog: If your dog has a notably long or short coat, FGF5 is likely part of the reason—no action needed, but it’s a neat genetic detail to know.

Full FGF5 gene page →

KRT71 is near-fixed at 100% for the wavy/curly variant. Coat curl phenotype varies across breeds at this fixation depending on modifier loci, and visible expression is not always curled even when the locus is fixed.

KRT71what this gene does

KRT71 is a gene that influences the curliness of a dog's coat. It helps determine whether a dog's fur is straight or has a distinctive curl.

For your dog: If your dog has a curly coat, KRT71 is likely part of the reason; it’s a natural variation, not a health concern.

Full KRT71 gene page →

MC1R is at 100% at the representative SNP. MC1R controls the switch between red-to-gold and black-to-brown pigment, with the e/e homozygous genotype producing the gold-to-red spectrum by blocking eumelanin (black and brown pigment).

MC1Rwhat this gene does

MC1R is a gene that influences coat color in dogs, affecting how pigments are produced in the fur.

For your dog: Knowing about MC1R gives insight into your dog's coat color but doesn't relate to health issues.

Full MC1R gene page →

Ears

MSRB3 is at 100% for the drop-ear allele, the genetic basis of the breed's signature dropped ear set.

MSRB3what this gene does

MSRB3 is a gene involved in the development of ear shape and structure in dogs.

For your dog: Understanding MSRB3 helps explain why your dog's ears look the way they do, but it isn't linked to any health issues.

Full MSRB3 gene page →

Skull shape

BMP3 sits at 82%, contributing to the breed's moderate, mesaticephalic head shape rather than the extreme brachycephalic form.

BMP3what this gene does

BMP3 is a gene that influences the shape of a dog's skull, particularly contributing to a shorter, broader head shape known as brachycephaly.

For your dog: If your dog has a broad, short skull, it's worth discussing with your vet how this might impact their health, even though BMP3 isn't directly tied to illness.

Full BMP3 gene page →

SMOC2 sits at 57%, contributing to the breed's moderate head shape.

SMOC2what this gene does

SMOC2 influences the shape of a dog's skull, particularly affecting how flat or short the face appears.

For your dog: If your dog has a short nose, it's worth discussing with your vet how this trait might impact their health over time.

Full SMOC2 gene page →
Mendelian-disease genetics

What genetic diseases do Collies carry?

From a panel of 250 Mendelian-disease variants screened in 1,054,293 dogs (Donner et al. 2023), Collies carry 5 of them at observable frequency. Carrier frequency is not clinical risk. Most recessive variants require two copies for disease expression; many dominant variants show incomplete penetrance. Read this as a population fingerprint of what's in the gene pool, not a per-dog prediction.

Collie Eye Anomaly (CEA)
Autosomal recessive
high 72.2%
n = 1,207 dogs · 1 variant tested · OMIA:000218-9615 · omia.org →
NHEJ1what this gene does

NHEJ1 is a gene involved in repairing breaks in DNA, helping maintain the integrity of genetic information in cells.

For your dog: If your dog belongs to one of the breeds known to carry this gene variant, it's worth discussing testing with your vet to understand any potential eye health risks.

MDR1 (Multidrug Resistance 1) Medication Sensitivity
Autosomal dominant
high 56.4%
n = 1,207 dogs · 1 variant tested · OMIA:001402-9615 · omia.org →
ABCB1what this gene does

ABCB1 is a gene that helps control how certain drugs are processed and cleared from a dog's body.

For your dog: If your dog is from a breed that carries this gene variant, ask your vet about medication sensitivities before giving any new drugs.

Degenerative Myelopathy (DM)
Autosomal recessive (Incomplete penetrance)
moderate 12.6%
n = 1,207 dogs · 1 variant tested · OMIA:000263-9615 · omia.org →
SOD1what this gene does

SOD1 is a gene that helps protect cells from damage caused by harmful molecules called free radicals.

For your dog: If your dog is a carrier of SOD1 variants, it's worth discussing with your vet, but remember carrier status doesn't mean your dog will get the disease.

Bardet-Biedl syndrome 2 or Progressive Retinal Atrophy (Discovered in the Shetland Sheepdog; BBS2-PRA)
Autosomal recessive
low <0.1%
n = 1,207 dogs · 1 variant tested · OMIA:002484-9615 · omia.org →
Exercise-Induced Collapse (EIC)
Autosomal recessive (Incomplete penetrance)
low <0.1%
n = 1,207 dogs · 1 variant tested · OMIA:001466-9615 · omia.org →
DNM1what this gene does

DNM1 is a gene that helps nerve cells communicate properly by managing how they send signals during muscle activity.

For your dog: If your dog belongs to one of the breeds known to carry this gene variant, it's worth discussing EIC with your vet, especially if your dog is very active or shows signs of weakness during exercise.

Source: Donner J et al. 2023. Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs. PLOS Genetics 19(2):e1010651 · Evidence: Limited (DTC ascertainment, tag-SNP proxy) · Confounding MEDIUM · License CC-BY-4.0 · Phene IDs from OMIA (Sydney School of Veterinary Science, The University of Sydney; DOI 10.25910/2AMR-PV70).
Sample size in this breed: 1,207 dogs from the Donner 2023 cohort.

Which Mendelian variants matter most for Collies?

The Mendelian-disease table above lists variants screened in 1,207 Collies (Donner 2023). Two dominate by carrier frequency and clinical impact.

Collie Eye Anomaly (CEA)

Collie Eye Anomaly in Collies is an autosomal-recessive developmental eye condition caused by a variant in the NHEJ1 gene. Affected dogs have retinal hypoplasia, choroidal hypoplasia, or in severe cases retinal detachment and blindness. The condition is present at birth and does not progress after early development.

72.2% of Collies in the Donner cohort carry at least one copy of the variant (n=1,207). That is nearly three in four. Testing is widely available through breed-club recommended laboratories. The Collie Club of America health committee recommends testing breeding stock and has maintained CEA screening protocols for decades.

MDR1 (Multidrug Resistance 1) Medication Sensitivity

MDR1 medication sensitivity in Collies is an autosomal-dominant condition caused by a variant in the ABCB1 gene. Dogs carrying the variant have reduced drug efflux in the blood-brain barrier and are hypersensitive to certain medications, most commonly ivermectin (used for heartworm prevention and parasite treatment). A standard dose can cause neurological toxicity: tremors, ataxia, lethargy, or death.

56.4% of Collies in the Donner cohort carry the variant (n=1,207). Donner S4 found only 1 of 2 at-risk dogs phenotype-confirmed, putting the maximum observed penetrance at 50%. The risk is real and avoidable with drug selection. Testing is available through commercial DNA panels. Any Collie with a positive MDR1 result should have a flag in their veterinary record to avoid ivermectin and related avermectins.

Degenerative Myelopathy (DM)

Degenerative Myelopathy in Collies is an autosomal-recessive condition with incomplete penetrance caused by a variant in the SOD1 gene. Affected dogs develop progressive rear-limb weakness and spinal-cord degeneration, typically in middle or older age. The condition is progressive and ultimately paralyzing.

12.6% of Collies carry at least one copy of the variant (n=1,207). Testing is available. Not every dog with two copies becomes symptomatic, which is why the inheritance is described as incomplete penetrance. The breed-club health committee monitors DM cases and recommends testing for breeding decisions.

Bardet-Biedl Syndrome 2 or Progressive Retinal Atrophy (BBS2-PRA) and Exercise-Induced Collapse (EIC)

Bardet-Biedl syndrome 2 (BBS2-PRA) in Collies is an autosomal-recessive retinal degeneration causing progressive vision loss. Exercise-Induced Collapse in Collies is an autosomal-recessive condition with incomplete penetrance that causes collapse during or after intense exercise.

Both variants appear at less than 0.1% carrier frequency in the Donner cohort (n=1,207). Neither is a present breeding concern in the current population.

How should I test my Collie?

A breed-specific panel from a CLIA-accredited laboratory is the high-yield path. The essential set for Collies is CEA, MDR1, and DM. The Collie Club of America maintains a list of recommended testing laboratories on their health pages.

What should I feed a Collie?

Feeding a Collie well means feeding around the breed’s known genetic vulnerabilities. The most consequential is MDR1 medication sensitivity, which shapes parasite-prevention and medication choices for every Collie. Two other genetics matter: DM’s mid-life onset window and the breed’s moderate hip dysplasia signal.

Heartworm and intestinal parasite prevention is MDR1-sensitive. Ivermectin (in Heartgard and many parasite treatments) is dangerous for Collie carriers of the MDR1 variant. This does not mean the diet itself changes, but it means the owner cannot use the most common and cheapest heartworm preventive. Milbemycin oxime (Interceptor) or spinosad (Comfortis) are ivermectin-free alternatives. The dietary consequence is minimal: the diet itself does not change, only the choice of parasite-prevention product.

Joint care matters for the breed’s hip dysplasia frequency. The Orthopedic Foundation for Animals reports 4.4% hip dysplasia prevalence across 10,547 Collie evaluations (OFA breed statistics, ofa.org/diseases/hip-dysplasia/, accessed 2024). This is lower than many large breeds but not negligible. A large-breed puppy formulation with controlled calcium (0.8-1.2% dry matter) and a calcium-to-phosphorus ratio between 1.1:1 and 2:1 supports healthy skeletal development. Adult-life weight management and moderate exercise (avoiding sprinting and jumping in growing puppies until 12 months of age) are equally important.

Degenerative Myelopathy becomes relevant in the second half of life. DM typically emerges between ages 5 and 14 in affected dogs, based on reported SOD1-associated DM case series (Awano et al. 2009, PNAS 106:2794-2799). There is no proven dietary prevention, but maintaining a lean body condition and joint mobility through appropriate exercise may slow progression. Antioxidant support (vitamin E and selenium at NRC 2006 levels or modestly above) is often recommended by neurologists, though the evidence base is limited. Standard adult maintenance diets with adequate antioxidants are sufficient unless a veterinarian flags a specific need.

Grain inclusion or exclusion is not a genetic vulnerability for Collies. The breed has no documented association with diet-related dilated cardiomyopathy as Goldens do. A grain-inclusive diet is no more protective for Collies than a grain-free one from a genetic standpoint. The choice is nutritional and economic, not a breed-specific mandate.

What we don’t know

The penetrance of MDR1 sensitivity is incompletely characterized. Donner S4 reported only 1 of 2 at-risk dogs phenotype-confirmed; the maximum penetrance is 50%. This means some Collies with the MDR1 variant will tolerate ivermectin exposure without overt toxicity, while others will show severe reactions. We do not yet know which individual dogs will react and which will not.

Degenerative Myelopathy’s incomplete penetrance is also unsettled. Not every Collie homozygous at the SOD1 locus becomes symptomatic. Environmental and genetic modifiers may govern whether a carrier develops clinical signs. The published analyses have not yet identified those modifiers.

CEA’s severity is heritable but incompletely predictable from genotype alone. Two affected littermates from the same cross may show different degrees of retinal involvement. The breed-club health surveys have documented this variation but the genetic basis remains unresolved.

Frequently asked questions about Collies

Are Collies good with children? Collies were bred for herding and have strong herding instinct toward moving objects, including small children. With socialization and training, they are typically gentle and patient. Supervision with young children is important, as is teaching children not to trigger herding behavior through running.

What is the most common genetic disease in Collies? Collie Eye Anomaly, caused by a variant in the NHEJ1 gene. 72.2% of Collies carry at least one copy (Donner 2023, n=1,207). Severity ranges from subclinical to blindness, with most carriers showing mild hypoplasia that does not affect vision.

Should I do a DNA test on my Collie? For breeding stock, yes. The Collie Club of America recommends testing for CEA, MDR1, and DM. Pet owners whose Collie will receive ivermectin-based parasite treatments should test for MDR1 to guide medication choices.

What should I avoid giving my Collie? Ivermectin-based heartworm preventives and parasite treatments if your Collie carries the MDR1 variant. The standard dose can cause severe neurological toxicity. Test first or ask your veterinarian about non-ivermectin alternatives like milbemycin oxime.

How long do Collies live? Breed-club surveys and OFA data align on a median lifespan near 12 years for Collies (Collie Club of America health pages, collieclub.net). Breed-club estimates align with this range. Collies are generally considered a long-lived breed within the large-breed category.

What is the best diet for a Collie? A balanced, age-appropriate diet from a manufacturer that runs feeding trials. For puppies, prioritize controlled calcium and a calcium-to-phosphorus ratio of 1.1:1 to 2:1. Avoid ivermectin-based parasite treatments; plan heartworm prevention around MDR1 status. In middle age and beyond, maintain lean body condition to support joint health and potentially slow DM progression if your dog is at genetic risk.

Can Collies compete in agility or dock diving? Yes, with caveats. Collies are athletic and capable of competitive sports. However, if your Collie carries the Exercise-Induced Collapse variant (currently rare in the breed), intense sprinting or sustained high-intensity activity may trigger collapse. Genetic testing is available; most Collies are not carriers and can safely train intensively.

Do Collies need special grooming? Collies have a double coat that sheds heavily. Brushing several times per week is standard maintenance. Shedding intensifies during spring and fall coat blows. This is cosmetic, not health-related, but it is worth planning for if you are a new owner.

A gift to human medicine

Collies are a natural model for human disease

Because the same genes cause the same conditions across species, the inherited conditions documented in Collies help researchers understand, and work toward treating, the human diseases they model. This is the dog advancing human medicine. The breed models the human disease; it does not have it, and this is not a prediction for your dog.

Human equivalents via OMIA → Mondo / OMIM. Model-of, not identity.
Documented in OMIA

Every condition recorded in the Collie

Beyond the testable carriers above, OMIA's literature catalogue records 10 genetic conditions in the Collie, 9 of which have a known human equivalent. This is the documented landscape across all Collies ever studied, not a prediction for any one dog.

Online Mendelian Inheritance in Animals (OMIA); Nicholas, Tammen & Sydney Informatics Hub, DOI 10.25910/2AMR-PV70
Documented in the breed's literature is not carrier status and not a forecast for an individual dog. Human equivalents are mapped via Mondo/OMIM. Carrier frequencies (above) are the separately-measured testable subset (Donner 2023).
The data behind this page

Where every number on this page came from.

This page draws on three primary data sources. Carrier frequencies for the Mendelian section come from Donner et al. 2023 (CC-BY-4.0). We grade these data at evidence Limited because the cohort is a direct-to-consumer ascertainment, which biases toward owners who chose to test their dogs. The panel also uses tag-SNP proxies for some variants rather than direct causal-variant assays. Limited is a study-design grade, not a quality grade: the Donner cohort is the largest open canine-genotype dataset in existence and we are grateful for it. We rate the confounding MEDIUM.

Population-genetic dimensions (heterozygosity, intra-breed PCA distance, nearest neighbors, trait-locus frequencies) come from CanVAS (Brundage 2026), harmonized through the Sniff Atlas. The exact release date and verification commit are pinned at the bottom of the page so a researcher can trace a number back to a specific snapshot. The disease-gene-variant graph comes from OMIA (Online Mendelian Inheritance in Animals; Nicholas, Tammen, and the Sydney Informatics Hub at the Sydney School of Veterinary Science, The University of Sydney; retrieved April 2026, DOI 10.25910/2AMR-PV70).

What this page does not yet have. Inheritance modes and per-disease penetrance evidence from Donner 2023 are now in the structured data for every variant the panel covers. Mondo, OMIM, Ensembl, and HGNC cross-references on gene pages remain pending, they arrive in December 2026 alongside the imputed 9.67M-variant CanVAS dataset via the OMIA SQL dump absorption. Until then, gene IDs carry NCBI Gene and OMIA phene URLs only; the wider human-homolog and disease-ontology cross-reference set fills in with that release.

How to cite this page. The computed dimensions on this page are derived from the open Sniff Atlas v1.0.1 (Gehring 2026, doi:10.5281/zenodo.20566358, CC-BY 4.0). Full citation formats including BibTeX, RIS, and CITATION.cff at sniff.world/cite.

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References
  1. Donner J, Freyer J, Davison S, Anderson H, Blades M, Honkanen L, et al. (2023). Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs. PLOS Genetics 19(2):e1010651. doi:10.1371/journal.pgen.1010651
  2. Brundage J, et al. (2026). CanVAS: a harmonized canine variant atlas. bioRxiv. doi:10.64898/2026.04.13.718238
  3. Nicholas, F.W., Tammen, I., & Sydney Informatics Hub. (2026). Online Mendelian Inheritance in Animals (OMIA) [dataset]. The University of Sydney. https://omia.org. doi:10.25910/2AMR-PV70 (retrieved April 2026).
Last updated
Sources: CanVAS (Brundage 2026) · Donner 2023 · OMIA