Plant & Animal Genomes XIII Conference

January 15-19, 2005
Town & Country Convention Center
San Diego, CA

Genetic Mapping Of Complex Traits In The Domestic Dog

Elaine A. Ostrander^1,2 , Nathan B. Sutter^1,2 , Michael A. Eberle² , Heidi G. Parker^1,2 , Barbara Pullar² , Ewen F. Kirkness³ , Leonid Kruglyak²

¹  NHGRI/NIH, 50 South Drive, MSC 8000, Bldg. 50, Room 5347, Bethesda MD 20892

²  Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N., D4-100, Seattle WA 98109

³  The Institute for Genomic Research, 9712 Medical Center Drive Rockville, MD 20850

Distinct dog breeds differ in morphology, behavior, and disease susceptibility. We have been interesting in identifying the historical links between modern breeds in order to establish a framework for understanding the inheritance of complex traits as well as for understanding the dynamics of population evolution. Our data demonstrate that breed barriers have resulted in strong genetic isolation among breeds, with breed membership accounting for ~30% of total genetic variation among dogs. Microsatellite data correctly assigns greater than 99% of individual dogs to breeds. Genetic cluster analysis groups modern breeds into four populations reflecting similarities in morphology, behavior and geographic origin. These results set the stage for mapping of complex traits in the dog.
We have therefore evaluated the degree of Linkage Disequilibrium (LD) at five randomly chosen loci, none of which is under obvious selective pressure, in five breeds. We screened approximately 20 unrelated dogs for each breed. Strikingly, LD in dogs is 20-100 times more extensive than in human populations and varies by as much as 10-fold between breeds. We observe low haplotype diversity within regions of high LD, with 80% of chromosomes in a breed carrying 2.1 – 3.5 haplotypes, as well as a high degree of haplotype sharing among breeds. In aggregate this suggests that a correspondingly smaller number of markers will be required for association studies in dogs than humans, and that a single SNP map of limited size can be used to map traits of interest in most breeds. Applications will be discussed.