狗的皮毛多种多样，有长毛、短毛、直毛、卷毛等。美国研究人员27日公布研究成果称，这些特征事实上仅由3种基因及它们的变种决定。

美国国家人类基因组研究所等机构研究人员分析了80个品种共1000多只狗的基因组。他们发现，狗的皮毛外观可分为3种简单属性：长度、卷曲情况及质地。这些属性分别由3种基因——FGF5、KRT71和RSPO2决定。这些基因或它们变种的组合可解释90％以上狗类皮毛的“表现型”，不过这仅适用于纯种狗。

例如，携带RSPO2基因变种的狗的毛发一般都较硬；同时携带RSPO2和KRT71基因变种的狗一般具有金属丝状卷发；而同时携带FGF5和RSPO2基因的狗基本都是长毛有须；而长毛狗一般都携带FGF5基因的变种。

研究人员还说，狗是大约1．5万年前由狼演化而来，但其基因组中与皮毛特征有关的基因变化很可能在最近几百年才开始。

这项研究成果将刊登在新一期《科学》杂志上。

推荐原始出处：

Science August 27, 2009 DOI: 10.1126/science.1177808

Coat Variation in the Domestic Dog Is Governed by Variants in Three Genes

Edouard Cadieu 1, Mark Neff 2, Pascale Quignon 1, Kari Walsh 2, Kevin Chase 3, Heidi G. Parker 1, Bridgett M. VonHoldt 4, Alison Rhue 2, Adam Boyko 5, Alexandra Byers 1, Aaron Wong 2, Dana S. Mosher 1, Abdel G. Elkahloun 1, Tyrone C. Spady 1, Catherine André 6, K. Gordon Lark 3, Michelle Cargill 5, Carlos D. Bustamante 7, Robert K. Wayne 4, Elaine A. Ostrander 1*

1 National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA.
2 Veterinary Genetics Laboratory, University of California, Davis, CA, 95616, USA.
3 Department of Biology, University of Utah, Salt Lake City, UT 84112, USA.
4 Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, 90095, USA.
5 Department of Biological Statistics and Computational Biology, Cornell University, Ithaca, NY 14853, USA.
6 UMR 6061, Faculté de Médecine, Rennes, France.
7 Affymetrix Corporation, Santa Clara, CA 95051, USA.; Present address: Genetics Navigenics, Inc., Foster City, CA 94404, USA.

Coat color and type are essential characteristics of domestic dog breeds. While the genetic basis of coat color has been well characterized, relatively little is known about the genes influencing coat growth pattern, length, and curl. We performed genome-wide association studies of more than 1000 dogs from 80 domestic breeds to identify genes associated with canine fur phenotypes. Taking advantage of both inter- and intrabreed variability, we identified distinct mutations in three genes, RSPO2, FGF5, and KRT71 (encoding R-spondin-2, fibroblast growth factor–5 and keratin-71, respectively), which together account for the majority of coat phenotypes in purebred dogs in the United States. This work illustrates that an array of varied and seemingly complex phenotypes can be reduced to the combinatorial effects of only a few genes.