Trait overview

Body size is extremely variable in canine breeds. Due to breeder selection, we are now seeing extremes of 40-fold size differences amongst breeds. The main genetic component that controls this size difference is Insulin-like growth factor 1 (IGF1), which is a gene that controls a potent growth hormone. Mutations in this gene contribute to the body size of modern dogs. Depending on what mutation is found on IGF1, this may account to up to 15 percent of body size variation between breeds.

Gene name(s)

IGF1

Inheritance

Multifactorial

Citations

Plassais J, vonHoldt BM, Parker HG, Carmagnini A, Dubos N, Papa I, Bevant K, Derrien T, Hennelly LM, Whitaker DT, Harris AC, Hogan AN, Huson HJ, Zaibert VF, Linderholm A, Haile J, Fest T, Habib B, Sacks BN, Benecke N, Outram AK, Sablin MV, Germonpré M, Larson G, Frantz L, Ostrander EA. Natural and human-driven selection of a single non-coding body size variant in ancient and modern canids. Curr Biol. 2022 Feb 28;32(4):889-897.e9. doi: 10.1016/j.cub.2021.12.036. Epub 2022 Jan 31. PMID: 35090588; PMCID: PMC8891063.

Callaway E. Big dog, little dog: mutation explains range of canine sizes. Nature. 2022 Feb;602(7895):18. doi: 10.1038/d41586-022-00209-0. PMID: 35087254.