Pug
31 Pugs in the atlas. Every number on this page has a source.
31 Pugs 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 Pug clusters consistently as Pug (100% of the 31 dogs here). At the trait loci, MSRB3 runs lower than average (2% here vs 80%); SMAD2 runs lower than average (0% here vs 74%). Dogs here sit in a relatively sparse region of the atlas, fewer close neighbors than typical.
Ranks 16 of 107 on the bottleneck severity scale, well into the upper quartile of population contraction.
Closest genetic neighbors in the atlas: Havanese, Minature Poodle, Toy Poodle, Miniature Pinscher, and Dachshund.
Median lifespan is 11.5 years, slightly shorter than expected for the breed size (7.25 kg).
What the genome says about Pug
Computed from the 18,477 research dogs in the Atlas.
- Havanese4.26
- Minature Poodle5.87
- Toy Poodle5.90
- Miniature Pinscher6.34
- Dachshund6.51
Frequency of the alternate allele in this breed at each locus's representative SNP.
| IGF1 | 100% |
| HMGA2 | 0% |
| SMAD2 | 0% |
| LCORL | 100% |
| STC2 | 100% |
| ADAMTS17 | 19% |
| FGF4·CFA18 | 100% |
| FGF4·CFA12 | 100% |
| RSPO2 | 58% |
| FGF5 | 100% |
| KRT71 | 56% |
| MC1R | 21% |
| MSRB3 | 2% |
| BMP3 | 100% |
| SMOC2 | 100% |
What does the genome say about how a Pug looks?
Pugs 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 near-fixed at 100% for the small-body allele, which keeps the breed compact relative to its working-line ancestors.
HMGA2 is at 0%, leaving most of the size signal to other loci in the panel.
SMAD2 is at 0%, leaving the height signal mostly to other size genes.
LCORL is near-fixed at 100%, the NCAPG/LCORL height locus that is one of the strongest single contributors to canine body size.
STC2 is near-fixed at 100%, modulating growth-axis signaling toward the breed's body-size set point.
ADAMTS17 is at 19%, the lower-frequency allele in this breed.
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 100%, the chondrodystrophic variant associated with intervertebral disc disease risk in breeds that carry it.
Coat type, length, and color
RSPO2 sits at 58% for the furnishings variant. Furnishings (the eyebrow-and-mustache pattern seen in Schnauzers and Wheaten Terriers) vary across the population at this intermediate frequency, and visible expression depends on the specific allele combination each dog carries.
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 sits at 56% for the wavy/curly variant. Coat curl varies across individuals at this intermediate frequency, and visible expression is also influenced by modifier loci.
MC1R is at 21% at the representative SNP, leaving the breed in the black-to-brown coat range under the dominant E allele.
Ears
MSRB3 is at 2% for the drop-ear allele, keeping the breed's ears upright and prick.
Skull shape
BMP3 is at 100%, contributing to the breed's brachycephalic skull shape.
SMOC2 is at 100%, the major locus contributing to the breed's brachycephalic face shape.
What genetic diseases do Pugs carry?
From a panel of 250 Mendelian-disease variants screened in 1,054,293 dogs (Donner et al. 2023), Pugs carry 25 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 31 pugs. We do not have yours.
Every pug 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).