The coats of domestic dogs show great variation—long, short, straight, wavy, curly, wiry, or smooth. To investigate how this variation arises, Cadieu et al. performed genome-wide association studies on 80 different dog breeds. The coat phenotype could be dissected into three simple traits of length, curl, and growth pattern or texture, with each trait controlled by one major gene, FGF5 (fibroblast growth factor–5), KRT71 (keratin-71), and RSPO2 (R-spondin–2), respectively. In combination, variants in these three genes alone account for the vast majority of the coat phenotypes in purebred dogs in the United States. Thus, a small number of simply inherited traits can be remixed to create extraordinary phenotypic variation.
E. Cadieu, M. W. Neff, P. Quignon, K. Walsh, K. Chase, H. G. Parker, B. M. VonHoldt, A. Rhue, A. Boyko, A. Byers, A. Wong, D. S. Mosher, A. G. Elkahloun, T. C. Spady, C. André, K. G. Lark, M. Cargill, C. D. Bustamante, R. K. Wayne, E. A. Ostrander, Coat variation in the domestic dog is governed by variants in three genes. Science 326, 150–153 (2009). [Abstract] [Full Text]