Marker Analysis of Dog Breeds to Identify Genes of Large Phenotypic Effect

[02:13 . 90]就大小和形态而言，家狗无疑是最多样化的物种。此外，许多构象特征在品种中是固定的，并且认为这些特征通常具有简单的遗传基础。因此，狗是鉴定对骨骼发育有相应影响的基因的良好模型。提出了一种新的实验设计，旨在揭示影响构象，被毛颜色和行为的特定基因。该设计采用病例对照方法，对具有相似性状的品种进行540个框架标记扫描。在标记子集中具有低变异性的基因组区域可能包含在品种中已成为选择对象的基因。统计和分子工具的定义，将允许精细绘图和最终鉴定的主要基因影响性状。为了证明该方法的可行性，我们提出了三个小型研究：1)对20个被认为是近亲繁殖的品种进行基因组扫描，以证明它们有足够的变异来满足我们的实验设计；2)对具有软骨发育不全表型的三个品种（短腿犬）进行基因组扫描，以表明可以识别该性状的基因；3)确定在一个品种中已知引起毛色表型的基因两侧区域的纯合性信号的程度。该项目将测试一种新方法的可行性，以发现对大小和构象有重大影响的基因。此外，激烈的选择在基因组中留下的足迹将被确定。这可能为基因定位提供新的方法，并提供对骨骼发育和进化的更好理解。

0213905WayneThe domestic dog is without question the most diverse species with regard to size and conformation. Further, many conformation traits are fixed in breeds and it is argued that these traits may often have a simple genetic basis. Therefore, the dog is a good model for identification of genes that have a consequential effect on skeletal development. A novel experimental design is presented that aims to uncover specific genes that influence conformation, coat color and behavior. The design utilizes a case controlled approach in which breed that share similar traits are scanned with 540 framework markers. Regions of the genome that have low variability in a subset of markers are likely to contain genes that have been the object of selection in breeds. Statistical and molecular tools are defined that will allow fine-scale mapping and eventual identification of major genes influencing traits. To demonstrate the viability of the approach, three small studies are proposed: 1) a genomic scan of 20 breeds thought to be inbred to demonstrate they have sufficient variation for our experimental design; 2) a genomic scan of three breeds sharing the achondroplasia phenotype (short legged dogs) to show that the gene for this trait can be identified; and 3) determination of the extent of homozygosity signal in regions flanking a gene known to cause a coat color phenotype in one breed. This project will test the feasibility of a new approach to discover genes that have consequential effects on size and conformation. Further, the footprint that intense selection leaves in the genome will be determined. This may enable new approaches for gene mapping and provide a better understanding of skeletal development and evolution.