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Complex segregation analysis of deafness in Dalmatians
T R Famula1, A M Oberbauer, C A Sousa
1Department of Animal Science, College of Agriculture and Environmental Sciences, University of California, Davis 95616, USA.
American Journal of Veterinary Research
|May 10, 2000
Summary
Pedigree analysis suggests a single gene influences deafness in Dalmatians, but doesn't fully explain its inheritance. Breeding unilaterally deaf, blue-eyed dogs is discouraged to reduce hearing loss incidence.
Area of Science:
- Canine genetics
- Animal audiology
- Complex segregation analysis
Background:
- Deafness is a significant concern in Dalmatian dogs.
- Understanding the genetic basis of deafness is crucial for breed health.
- Previous studies suggest a genetic component to Dalmatian deafness.
Purpose of the Study:
- To evaluate a major locus model for deafness in Dalmatians using pedigree analysis.
- To investigate the feasibility of a single gene controlling deafness in this breed.
- To identify genetic correlations between deafness and other traits.
Main Methods:
- Pedigree analysis of 605 purebred Dalmatians across 42 families.
- Brainstem auditory-evoked response used to assess hearing (normal, unilateral, bilateral deafness).
- Complex segregation analysis with regressive logistic models.
Main Results:
- Prevalence of hearing loss: 11% unilaterally deaf, 5% bilaterally deaf.
- Evidence for a single allele (frequency 0.21) affecting deafness prevalence.
- The single locus model did not fully explain deafness inheritance and incidence.
- Strong genetic correlations observed between deafness, eye color, and coat color patch.
Conclusions:
- A single major locus is insufficient to fully explain Dalmatian deafness.
- Strong interrelationships exist among deafness, eye color, and coat color.
- Discouraging breeding of unilaterally deaf, blue-eyed dogs may reduce hearing loss incidence.