Evaluation of quantitative trait loci for hip dysplasia in Labrador Retrievers.
OBJECTIVE
To identify the quantitative trait loci (QTL) that contribute to hip dysplasia in dogs.


METHODS
192 Labrador Retrievers.


METHODS
Hip dysplasia was measured by use of the Norberg angle (NA), dorsolateral subluxation (DLS) score, and distraction index (DI). Genome-wide screening was conducted by use of 276 unique microsatellites. Linkage analysis was performed with a variance-based linear model. Logarithm of the odds (LOD) scores were reported when values were > 2.0.


RESULTS
Canis familiaris autosomes (CFAs) 01, 02, 10, 20, 22, and 32 harbored significant QTL at LOD scores > 2.0. Among the 6 QTL, the QTL on CFA02 had not been reported to harbor QTL for hip dysplasia. The highest LOD score of 3.32 on CFA20 contributed to the second principal component of the DLS score and NA of the right hip joint. The QTL that was mapped on CFA01 (LOD score of 3.13 at 55 centimorgans) was located on the same chromosome reported to harbor a QTL for hip dysplasia in Portuguese Water Dogs and German Shepherd Dogs. In this study, CFAs 10, 20, 22, and 32 harbored QTL for hip dysplasia that have been identified in a Labrador Retriever-Greyhound pedigree and in German Shepherd Dogs.


CONCLUSIONS
Multiple QTL were clearly involved with hip dysplasia. Identification of these QTL will enable fine-resolution mapping and subsequent assessment of candidate genes within the refined intervals to enable researchers to develop genetic screening tests and preventative and novel therapeutic regimens.
Phavaphutanon
Janjira
J
Center for Agricultural Biotechnology, Kasetsart University, Kamphaeng Saen, Nakhon Pathom, Thailand.
Mateescu
Raluca G
RG
Tsai
Kate L
KL
Schweitzer
Peter A
PA
Corey
Elizabeth E
EE
Vernier-Singer
Margaret A
MA
Williams
Alma J
AJ
Dykes
Nathan L
NL
Murphy
Keith E
KE
Lust
George
G
Todhunter
Rory J
RJ
D000818:Animals; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004283:Dog Diseases / Q000235:genetics*; D004285:Dogs; D005260:Female; D005838:Genotype; D006619:Hip Dysplasia, Canine / Q000235:genetics*; D006621:Hip Joint / Q000473:pathology; D008098:Litter Size; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D010375:Pedigree; D010641:Phenotype; D040641:Quantitative Trait Loci; D013045:Species Specificity
D004247:DNA