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

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

0213905 Wayne The 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.