毋庸置疑，不同品种的狗身体形状是不一样的。但你可能还没有意识到，研究狗的基因组或有助于改善人类的健康。因此，当你下一次再深情注视着狗狗的眼睛或者在它们耳朵后面抓痒的时候，留意一下它们鼻子的长度或者身体的大小。尽管这些性状在不同的品种中有很大的变化，但研究人员发现其实这些差异只是由少数几个基因区域决定的。
研究人员表示，探索不同品种的狗之间的遗传差异或最终能帮助我们理解人类的生物医学特性，比如身高、头发颜色、体重等，这些性状通常受我们体内成百上千不同基因组成的网络影响。而识别狗身上的那些含有遗传"开关"的重要区域，将为我们找到影响人类健康的变异提供重要线索。
这项研究是至今为止关于狗的最全面的遗传学分析，研究人员对900多只狗进行了基因分型，并评估了将近60种特定的身体性状，结果发现少数的基因区域就决定了大部分狗的外观。
斯坦福大学遗传学教授Carlos Bustamante表示："通过对狗的基因组分析，我们发现只有6或7个位点是必需的，它们就能解释80%左右的差异，比如不同品种狗的升高和体重变化。而在人类中，这些性状不是由数百甚至成千的变异所控制的。"
这项研究结果发布在8月10日的PLoS Biology杂志上。
推荐原文出处：
PLoS Biol doi:10.1371/journal.pbio.1000451
A Simple Genetic Architecture Underlies Morphological Variation in Dogs
Adam R. Boyko1,2#, Pascale Quignon3#, Lin Li2#, Jeffrey J. Schoenebeck3, Jeremiah D. Degenhardt2, Kirk E. Lohmueller2, Keyan Zhao1,2, Abra Brisbin2, Heidi G. Parker3, Bridgett M. vonHoldt4, Michele Cargill5, Adam Auton2, Andy Reynolds2, Abdel G. Elkahloun3, Marta Castelhano6, Dana S. Mosher3, Nathan B. Sutter2,6, Gary S. Johnson7, John Novembre4, Melissa J. Hubisz2, Adam Siepel2, Robert K. Wayne4, Carlos D. Bustamante1,2?*, Elaine A. Ostrander3?*
1 Department of Genetics, Stanford School of Medicine, Stanford, California, United States of America, 2 Department of Biological Statistics and Computational Biology, Cornell University, Ithaca, New York, United States of America, 3 Cancer Genetic Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America, 4 Department of Ecology and Environmental Biology, University of California, Los Angeles, California, United States of America, 5 Affymetrix Corporation, Santa Clara, California, United States of America, 6 Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America, 7 Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, United States of America
Domestic dogs exhibit tremendous phenotypic diversity, including a greater variation in body size than any other terrestrial mammal. Here, we generate a high density map of canine genetic variation by genotyping 915 dogs from 80 domestic dog breeds, 83 wild canids, and 10 outbred African shelter dogs across 60,968 single-nucleotide polymorphisms (SNPs). Coupling this genomic resource with external measurements from breed standards and individuals as well as skeletal measurements from museum specimens, we identify 51 regions of the dog genome associated with phenotypic variation among breeds in 57 traits. The complex traits include average breed body size and external body dimensions and cranial, dental, and long bone shape and size with and without allometric scaling. In contrast to the results from association mapping of quantitative traits in humans and domesticated plants, we find that across dog breeds, a small number of quantitative trait loci (≤3) explain the majority of phenotypic variation for most of the traits we studied. In addition, many genomic regions show signatures of recent selection, with most of the highly differentiated regions being associated with breed-defining traits such as body size, coat characteristics, and ear floppiness. Our results demonstrate the efficacy of mapping multiple traits in the domestic dog using a database of genotyped individuals and highlight the important role human-directed selection has played in altering the genetic architecture of key traits in this important species.
