[Analysis of the mode of inheritance for distichiasis in the Elo dog breed using complex segregation analyses]. / Analyse des Erbgangs von Distichiasis bei der Hunderasse Elo mittels komplexen Segregationsanalysen.

The inheritance of distichiasis was analyzed in the dog breed Elo using complex segregation analyses. The different hypotheses of monogenic, mixed-monogenic-polygenic and polygenic inheritance as well as a pure environmental model were tested. In further analyses the number of examined Elo dogs per ophthalmologist and the proportion of genes of Eurasian and Old English Sheepdogs were included in the models as covariates. Seven families were randomly collected for the analyses. The seven families comprised a total of 296 animals with 218 examined and 65 affected dogs. A genetic component was verified for the prevalence of distichiasis. Mixed models with a recessive, dominant or arbitrary major gene effect and the polygenic model represented likely hypotheses of inheritance. The prevalence of distichiasis observed was insufficiently explained by non-genetic factors and the breed composition. Therefore, a model only including non-genetic factors and the breed composition could be excluded.

[Analysis of the prevalence of distichiasis in the dog breed Elo]. / Analyse der Prävalenz von Distichiasis bei der Hunderasse Elo.

The Elo is a recently established dog breed in which the eye anomaly distichiasis has been frequently observed. Out of a total of 234 Elo dogs ophthalmologically examined over four years, 27.8% of the dogs showed between 1 and 31 distichia. There were twice as many distichia in the upper than in the lower eyelid. Litter size, the number of examinations of Elo dogs per ophthalmologist and the proportion of genes of the Eurasian dog had a significant influence on the prevalence of distichiasis. The error probability for the inbreeding coefficient and the proportion of genes of the Old English Sheepdog were just above the significance limit of p = 0.05. No significance was found for the remaining effects. Heritability for distichiasis was estimated using a linear animal model. After transformation of the linear observed estimate onto the underlying liability scale the heritability estimate was h2 = 0.43.

[Population genetic analysis of the new dog breed Elo]. / Populationsgenetische Analyse der neu gezüchteten Hunderasse Elo.

The breeding of the dog breed Elo was started in 1987. This dog breed was established by using 16 dogs of nine different breeds. All pedigree information of the dogs from 1987 to 2002 was included for the analysis of the proportion of genes of the different founder breeds, of the inbreeding coefficient, and relationship coefficients. Additionally, the number of died puppies per litter were investigated. The Eurasian dog breed contributed about 48% of the genes in the whole Elo dog population. Old English sheepdog and Chow Chow contributed about 23% and 10% of the genes. The other dog breeds were of minor importance. The mean inbreeding and relationship coefficients of the whole Elo dog population were 12.04% and 19.22%, respectively. With the exception of 3.5% of animals, all Elo dogs were related to each other. The mean litter size was 6.39 puppies. The percentage of stillborn puppies per litter averaged at 9.47%. The inbreeding coefficients of the puppies and of their dams, the age of the sire and the dam at the time of birth of the puppies, the litter size, the puppies' year of birth and the proportion of genes of the Chow Chow showed a significant effect on the number of stillborn puppies per litter. The heritability for the frequency of stillborn puppies was estimated using a linear animal model. After transformation of the linear estimates to the underlying liability scale, the heritability amounted to h2 = 0.15.