Skip to main content
snıff
Brachycephaly

SMOC2

chr1:56,380,603-56,539,474 · UU_Cfam_GSD_1.0

short-face candidate

Atlas-wide
Frequency
75%
dog-weighted average
Breeds with data
208
of 215
Dogs contributing
13,523
CanVAS Atlas
What the frequency means

SMOC2 chr1:56.4Mb (Marchant 2017). Top brachycephaly hit in our village-baseline selection scan at |dP|=0.85. The H1 hardening test (logistic regression of brachy phenotype on the rep SNP) showed R^2=0.05 alone, vs R^2=0.96 with a genome-wide PRS - the rep SNP is necessary-but-not-sufficient.

High frequency means

short-face allele common at this rep SNP - BUT brachy is polygenic and SMOC2 alone does not cleanly tag the phenotype (some non-brachy breeds also read high here, e.g. Afghan Hound, Cardigan Welsh Corgi)

Low frequency means

long-face allele common - this direction reliably distinguishes non-brachy from brachy/intermediate (Bull Terrier, Leonberger, Newfoundland, Saint Bernard read at the bottom)

Top 10 breeds, highest frequency
  1. Afghan Hound hound
    100% n=21
  2. 100% n=14
  3. 100% n=102
  4. 100% n=8
  5. Lhasa Apso non_sporting
    100% n=26
  6. Maltese toy
    100% n=96
  7. 100% n=24
  8. Pug toy
    100% n=31
  9. 100% n=33
  10. Shih Tzu toy
    100% n=38
Bottom 10 breeds, lowest frequency
  1. 0% n=10
  2. Leonberger working
    2% n=25
  3. Bull Terrier terrier
    2% n=44
  4. Newfoundland working
    12% n=182
  5. Saint Bernard working
    13% n=37
  6. Irish Setter sporting
    17% n=23
  7. Schipperke non_sporting
    20% n=40
  8. English Bulldog non_sporting
    20% n=10
  9. Boxer working
    22% n=192
  10. Shiba Inu non_sporting
    25% n=16
Methodology

Frequency is measured at the typed-backbone 1:56398416 on chr1, 56.4 Mb (inside the gene body). Alleles A/G. Coordinates from ensembl symbol UU Cfam GSD 1.0. Per-breed frequencies are computed across all CanVAS dogs labelled with that breed (missing genotypes excluded). See methodology for the full pipeline.

Last updated
Sources: CanVAS (Brundage 2026) · OMIA · Dog10K (Meadows 2023)