Mixed inheritance of equine recurrent airway obstruction.
- Gerber V Equine Clinic, Department of Veterinary Clinical Studies, Vetsuisse-Faculty, University of Berne, Switzerland. vinzenz.gerber@knp.unibe.ch
- Baleri D
- Klukowska-Rötzler J
- Swinburne JE
- Dolf G
- 2009-08-04
Published in:
- Journal of veterinary internal medicine. - 2009
Animals
Genetic Predisposition to Disease
Horse Diseases
Horses
Lung Diseases, Obstructive
Models, Genetic
English
BACKGROUND
Mode of inheritance of equine recurrent airway obstruction (RAO) is unknown.
HYPOTHESIS
Major genes are responsible for RAO.
ANIMALS
Direct offspring of 2 RAO-affected Warmblood stallions (n = 197; n = 163) and a representative sample of Swiss Warmbloods (n = 401).
METHODS
One environmental and 4 genetic models (general, mixed inheritance, major gene, and polygene) were tested for Horse Owner Assessed Respiratory Signs Index (1-4, unaffected to severely affected) by segregation analyses of the 2 half-sib sire families, both combined and separately, using prevalences estimated in a representative sample.
RESULTS
In all data sets the mixed inheritance model was most likely to explain the pattern of inheritance. In all 3 datasets the mixed inheritance model did not differ significantly from the general model (P= .62, P= 1.00, and P= .27) but was always better than the major gene model (P < .01) and the polygene model (P < .01). The frequency of the deleterious allele differed considerably between the 2 sire families (P= .23 and P= .06). In both sire families the displacement was large (t= 17.52 and t= 12.24) and the heritability extremely large (h(2)= 1).
CONCLUSIONS AND CLINICAL RELEVANCE
Segregation analyses clearly reveal the presence of a major gene playing a role in RAO. In 1 family, the mode of inheritance was autosomal dominant, whereas in the other family it was autosomal recessive. Although the expression of RAO is influenced by exposure to hay, these findings suggest a strong, complex genetic background for RAO.
Mode of inheritance of equine recurrent airway obstruction (RAO) is unknown.
HYPOTHESIS
Major genes are responsible for RAO.
ANIMALS
Direct offspring of 2 RAO-affected Warmblood stallions (n = 197; n = 163) and a representative sample of Swiss Warmbloods (n = 401).
METHODS
One environmental and 4 genetic models (general, mixed inheritance, major gene, and polygene) were tested for Horse Owner Assessed Respiratory Signs Index (1-4, unaffected to severely affected) by segregation analyses of the 2 half-sib sire families, both combined and separately, using prevalences estimated in a representative sample.
RESULTS
In all data sets the mixed inheritance model was most likely to explain the pattern of inheritance. In all 3 datasets the mixed inheritance model did not differ significantly from the general model (P= .62, P= 1.00, and P= .27) but was always better than the major gene model (P < .01) and the polygene model (P < .01). The frequency of the deleterious allele differed considerably between the 2 sire families (P= .23 and P= .06). In both sire families the displacement was large (t= 17.52 and t= 12.24) and the heritability extremely large (h(2)= 1).
CONCLUSIONS AND CLINICAL RELEVANCE
Segregation analyses clearly reveal the presence of a major gene playing a role in RAO. In 1 family, the mode of inheritance was autosomal dominant, whereas in the other family it was autosomal recessive. Although the expression of RAO is influenced by exposure to hay, these findings suggest a strong, complex genetic background for RAO.
- Language
-
- English
- Open access status
- bronze
- Identifiers
-
- DOI 10.1111/j.1939-1676.2009.0292.x
- PMID 19645845
- Persistent URL
- https://sonar.ch/global/documents/162565
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