Great Pyrenees
20 Great Pyreneess in the atlas. Every number on this page has a source.
20 Great Pyreneess in the Sniff Atlas. Population-genetic snapshot, Mendelian carrier frequencies from Donner 2023, and the data substrate's release version, sample sizes, and evidence tier on every claim.
In the atlas, the Great Pyrenees clusters consistently as Great Pyrenees (100% of the 20 dogs here). At the trait loci, MSRB3 runs lower than average (23% here vs 80%); HMGA2 runs higher than the atlas average (95% here vs 56%). Dogs here sit in a relatively sparse region of the atlas, fewer close neighbors than typical.
Only 20 dogs of this breed in the atlas, modestly sampled.
Closest genetic neighbors in the atlas: village dog Portugal, Keeshond, Portuguese Water Dog, Basset Hound, and village dog Peru Cusco.
What the genome says about Great Pyrenees
Computed from the 18,477 research dogs in the Atlas.
- Village Dog Portugal5.08
- Keeshond5.50
- Portuguese Water Dog5.87
- Basset Hound5.89
- Village Dog Peru Cusco6.07
Frequency of the alternate allele in this breed at each locus's representative SNP.
| IGF1 | 21% |
| HMGA2 | 95% |
| SMAD2 | 100% |
| LCORL | 100% |
| STC2 | 40% |
| ADAMTS17 | 57% |
| FGF4·CFA18 | 93% |
| FGF4·CFA12 | 65% |
| RSPO2 | 23% |
| FGF5 | 100% |
| KRT71 | 100% |
| MC1R | 98% |
| MSRB3 | 23% |
| BMP3 | 50% |
| SMOC2 | 73% |
What does the genome say about how a Great Pyrenees looks?
Great Pyreneess 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.
Size and build
IGF1 is at 21% for the small-body allele, leaving the breed firmly in the larger end of the dog body-size spectrum.
HMGA2 is near-fixed at 95%, reinforcing the breed's size signal through a second locus on chromosome 10.
SMAD2 is near-fixed at 100%, a chromosome-7 height locus differentiating small from giant breeds.
LCORL is near-fixed at 100%, the NCAPG/LCORL height locus that is one of the strongest single contributors to canine body size.
STC2 sits at 40%.
ADAMTS17 sits at 57%. ADAMTS17 is a body-size locus also linked to lens disorders.
Leg length
The FGF4 retrogene on chromosome 18 is near-fixed in this breed at 93%. 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 sits at 65%, the chondrodystrophic variant.
Coat type, length, and color
RSPO2 is at 23% for the furnishings allele. The breed does not carry the eyebrows-and-mustache pattern of Wheatens, Schnauzers, or wire-haired terriers.
FGF5 is at 100% 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.
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.
MC1R is at 98% 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).
Ears
MSRB3 is at 23% for the drop-ear allele, keeping the breed's ears upright and prick.
Skull shape
BMP3 sits at 50%, contributing to the breed's moderate, mesaticephalic head shape rather than the extreme brachycephalic form.
SMOC2 sits at 73%, contributing to the breed's moderate head shape.
What genetic diseases do Great Pyreneess carry?
From a panel of 250 Mendelian-disease variants screened in 1,054,293 dogs (Donner et al. 2023), Great Pyreneess carry 23 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.
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.
We have 20 great pyreneess. We do not have yours.
Every great pyrenees added sharpens the breed's genetic neighborhood. Enrollment is free. The data stays open. The star is permanent.
- Donner J, Anderson H, Davison S, et al. (2023). Frequency and distribution of 152 genetic disease variants in over 1,000,000 mixed-breed and purebred dogs. PLOS Genetics 19(2):e1010651. doi:10.1371/journal.pgen.1010651
- Brundage J, et al. (2026). CanVAS: a harmonized 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).