Quantitative genetics of traits associated with hip dysplasia in a canine pedigree constructed by mating dysplastic Labrador Retrievers with unaffected Greyhounds.
OBJECTIVE
To determine the genetic influence on expression of traits associated with canine hip dysplasia.


METHODS
193 dogs from an experimental canine pedigree.


METHODS
An experimental canine pedigree was developed for linkage analysis of hip dysplasia by mating dysplastic Labrador Retrievers with nondysplastic Greyhounds. A statistical model was designed to test the effects of Labrador Retriever and Greyhound alleles on age at detection of femoral capital epiphyseal ossification, 8-month distraction index, and 8-month dorsolateral subluxation score.


RESULTS
The additive effect was significant for age at detection of femoral capital epiphyseal ossification. Restricted maximum likelihood estimates (+/-SD) for this trait were 6.4+/-1.95, 10.2+/-2.0, 10.8+/-3.1, 11.4+/-2.1, and 13.6+/-4.6 days of age for Greyhounds, Greyhound backcross dogs, F1 dogs, Labrador Retriever backcross dogs, and Labrador Retrievers, respectively. The additive effect was also significant for the distraction index. Estimates for this trait were 0.21+/-0.07, 0.29+/-0.15, 0.44+/-0.12, 0.52+/-0.18, and 0.6+/-0.17 for the same groups, respectively. For the dorsolateral subluxation score, additive and dominance effects were significant. Estimates for this trait were 73.5+/-4.1, 71.3+/-6.5, 69.1+/-6.0, 50.6+/-12.9, and 48.4+/-7.7%, respectively, for the same groups.


CONCLUSIONS
In this canine pedigree, traits associated with canine hip dysplasia are heritable. Phenotypic differences exist among founder dogs of each breed and their crosses. This pedigree should be useful for identification of quantitative trait loci underlying the dysplastic phenotype.
Bliss
Stuart
S
Department of Clinical Sciences, College of Agricultural and Life Sciences, Cornell University, Ithica, NY 14853, USA.
Todhunter
Rory J
RJ
Quaas
Richard
R
Casella
George
G
Wu
Rongling
R
Lust
George
G
Williams
Alma Jo
AJ
Hamilton
Samuel
S
Dykes
Nathan L
NL
Yeager
Amy
A
Gilbert
Robert O
RO
Burton-Wurster
Nancy I
NI
Acland
Gregory M
GM
D000818:Animals; D003433:Crosses, Genetic; D004285:Dogs; D005260:Female; D008040:Genetic Linkage / Q000235:genetics; D006619:Hip Dysplasia, Canine / Q000000981:diagnostic imaging / Q000235:genetics*; D008297:Male; D008957:Models, Genetic; D015233:Models, Statistical; D010375:Pedigree; D040641:Quantitative Trait Loci / Q000235:genetics*; D011859:Radiography