Nova Scotia Duck Tolling Retriever
The tested variant with the highest allele frequency is Chondrodystrophy and Intervertebral Disc Disease Risk, at 29% among the 63 Nova Scotia Duck Tolling Retrievers tested (Donner 2023; gene copies, not dogs), then Progressive Rod-Cone Degeneration (11%) and Collie Eye Anomaly (7.1%).
Also known as Duck Toller, Little Red Duck Dog, Little River Duck Dog, and Toller.
Which disease variants turn up in Nova Scotia Duck Tolling Retrievers?
From a panel of 250 Mendelian-disease variants screened in 1,054,293 dogs (Donner et al. 2023), 7 turn up in Nova Scotia Duck Tolling Retrievers at observable frequency. The figure beside each is its allele frequency. Of the gene copies tested in this breed, the share that carry the variant. Every dog carries two copies, so this is not the share of dogs. It 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.
FGF4what this gene does
FGF4 influences leg length by affecting bone growth, leading to shorter legs in certain breeds.
For your dog: If your dog is from a breed known to carry this gene, it's worth discussing spinal health with your vet, but being a carrier doesn’t guarantee problems.
PRCDwhat this gene does
PRCD is a gene involved in the health of a dog's retina, the part of the eye that detects light and helps with vision.
For your dog: If your dog belongs to a breed known to carry PRCD changes, it's worth discussing eye health and potential genetic testing with your vet.
PDK4what this gene does
PDK4 helps regulate how cells use energy, especially in the heart muscle.
For your dog: If your dog is one of the breeds known to carry this gene, it’s worth discussing heart health with your vet, but being a carrier doesn’t mean your dog will develop disease.
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.
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.
What these results mean for a Nova Scotia Duck Tolling Retriever
About 29 in every 100 copies of this gene in the 63 Nova Scotia Duck Tolling Retrievers tested carry this change (Donner 2023).
- Extra copies of a growth gene called FGF4 shape a dog's legs and back. The copy on chromosome 12 is the one linked to disc disease. The copy on chromosome 18 makes legs shorter.
OMIA 000157-9615
“Two FGF4 retrogenes (FGF4L1 on chromosome 18 and FGF4L2 on chromosome 12) have been identified to cause dwarfism across many dog breeds.” OMIA 000157-9615
“Brown et al. (2017) reported that an FGF4 retrogene insertion in chromosome CFA12” OMIA 000157-9615
- Carrying it raises the risk, but it can't tell you which dog will have a disc problem. In Dachshunds, researchers found the test on its own isn't a reliable guide.
OMIA 000157-9615
“the FGF4 retrogene insertion on CFA12 is not a valid risk indicator on its own” OMIA 000157-9615
What to do
Ask your vet what the result means for your dog. The sources here don't say what lowers the risk for a dog that carries it.
Not tested, or a mix
Without a test, no one can tell. Short legs don't tell you either: the disc copy and the short-leg copy are different.
A heart (DCM) test that doesn't hold up
Not a reliable testAbout 25 in every 100 copies of this gene in the 63 Nova Scotia Duck Tolling Retrievers tested carry this change (Donner 2023).
- This gene change was linked to a heart disease called DCM in Dobermans, but it hasn't been shown to cause it. The curated record says a test for it isn't a good guide to heart risk, even in Dobermans.
OMIA 000162-9615
“it is evident that any DNA test based on this marker will not be a good indicator of liability to this disorder in Dobermans” OMIA 000162-9615
What to do
A result for this one isn't, by itself, a reason for heart tests. Whether to check your dog's heart is a conversation to have with your vet.
Not tested, or a mix
Outside the Doberman, no one has shown what this change means.
About 5 in every 100 copies of this gene in the 63 Nova Scotia Duck Tolling Retrievers tested carry this change (Donner 2023).
- DM slowly damages the spinal cord in adult dogs, until the back legs stop working. Nothing yet can stop it.
OMIA 000263-9615
“This is an adult onset degeneration of the spinal cord that progresses to paraplegia and tetraparesis. There is no successful treatment. A genetic test is available.” OMIA 000263-9615
- Two copies of the SOD1 gene change mean a dog is at risk, not that it will get sick. Some dogs with two copies never do.
OMIA 000263-9615
“some homozygous mutant dogs had no signs of degenerative myelopathy, which suggests incomplete penetrance or other causative loci” OMIA 000263-9615
- One copy makes a dog a carrier. In the study that found this change, every dog with DM that was tested had two copies.
OMIA 000263-9615
“All affected dogs tested were homozygous mutant.” OMIA 000263-9615
What to do
A DNA result isn't a diagnosis. If the way your dog walks changes, take that and the result to your vet.
Not tested, or a mix
Without a test, no one can tell how many copies your dog has. How common it is in a breed says nothing about one dog.
Other names
The Nova Scotia Duck Tolling Retriever is also recorded as Duck Toller, Little Red Duck Dog, Little River Duck Dog, Toller, Tolling Retriever, and Yarmouth Toller.
Identified as Nova Scotia Duck Tolling Retriever (VBO:0200964) in the Vertebrate Breed Ontology (Mullen et al. 2025, CC-BY 4.0) · registry IDs FCI 312 · iDog 173 · VeNom 15126.
For researchers Population genetics, disease models and every recorded condition Open the research detail for the Nova Scotia Duck Tolling Retriever
In the atlas, the Nova Scotia Duck Tolling Retriever clusters consistently as Nova Scotia Duck Tolling Retriever (100% of the 52 dogs here). Dogs here sit in a relatively sparse region of the atlas, fewer close neighbors than typical.
What the atlas genotypes say about Nova Scotia Duck Tolling Retriever
Computed from the 14,478 CanVAS dogs in the Atlas, on an imputed genotype backbone: 77,215 directly typed sites per dog, imputed to 9.67 million variants.
The confidence below counts dogs, not reads: it is the size of the sample, and it is separate from how the genotypes were measured.
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.
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.
Nova Scotia Duck Tolling Retrievers are a natural model for human disease
Because the same genes cause the same conditions across species, the inherited conditions documented in Nova Scotia Duck Tolling Retrievers 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.
- amyotrophic lateral sclerosis type 1, modeled by the breed's Degenerative myelopathy via SOD1, the same underlying biology.
- OMIM:615621, modeled by the breed's Addison’s disease and multiple autoimmune syndrome, RESF1-related , the same underlying biology.
- dilated cardiomyopathy 1A, modeled by the breed's Cardiomyopathy, dilated , the same underlying biology.
- developmental and epileptic encephalopathy, 39, modeled by the breed's Cerebellar degeneration-myositis complex, SLC25A12-related , the same underlying biology.
- OMIM:611290, modeled by the breed's Choroidal hypoplasia, NHEJ1-related , the same underlying biology.
- OMIM:611681, modeled by the breed's Cleft lip with or without cleft palate, ADAMTS20-related , the same underlying biology.
Every condition recorded in the Nova Scotia Duck Tolling Retriever
Beyond the testable carriers above, OMIA's literature catalogue records 13 genetic conditions in the Nova Scotia Duck Tolling Retriever, 10 of which have a known human equivalent. This is the documented landscape across all Nova Scotia Duck Tolling Retrievers ever studied, not a prediction for any one dog.
- Degenerative myelopathy Autosomal recessiveHuman equivalent: amyotrophic lateral sclerosis type 1
- Human equivalent: OMIM:615621
- Cardiomyopathy, dilated Multifactorial (OMIA); Autosomal dominant (Incomplete penetrance) (Donner 2023)Human equivalent: dilated cardiomyopathy 1A
- Cardiomyopathy, dilated, LMNA-related Probably autosomal recessiveHuman equivalent: dilated cardiomyopathy 1A
- Cerebellar degeneration-myositis complex, SLC25A12-related Autosomal recessiveHuman equivalent: developmental and epileptic encephalopathy, 39
- Choroidal hypoplasia, NHEJ1-related Autosomal recessiveHuman equivalent: OMIM:611290
- Cleft lip with or without cleft palate, ADAMTS20-related Autosomal recessiveHuman equivalent: OMIM:611681
- Cleft palate 1, DLX6-related Autosomal recessiveHuman equivalent: isolated Pierre-Robin syndrome
- Degenerative encephalopathy, RB1CC1-related Autosomal recessiveHuman equivalent: OMIM:606837
- Progressive rod-cone degeneration, PRCD-related Autosomal recessiveHuman equivalent: retinitis pigmentosa 36
- Intervertebral disc disease Autosomal dominant
Where every number on this page came from.
This page draws on three primary data sources. Allele 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 in the structured data for every variant the panel covers. Mondo, OMIM, Ensembl, and HGNC cross-references live on the gene and disease pages this page links to, rather than being repeated here. What is still absent from this breed page is anything not in the cited panel, and each such gap carries its cause where it appears.
How to cite this page. The computed dimensions on this page are derived from the open Sniff Atlas v1.0.2 (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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- 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
- Brundage DM (2026). CanVAS: A Harmonized and Imputed Canine Variant Atlas. bioRxiv. doi:10.64898/2026.04.13.718238
- 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).