Effect of inbreeding on the occurrence of genetic defects in Chinese Crested dogs

The aim of the study was to analyse the impact of inbreeding on the frequency of hereditary diseases and the number of genetically tested dogs. The pedigrees of 100 Chinese Crested dogs from Polish Kennel Club and information about genetic tests for hereditary eye diseases and other veterinary diagnoses were collected. Inbreeding coefficients and relatedness were estimated for all dogs examined. The relationship between the level of inbreeding and genetic testing was analysed with logistic regression. The relationship between the occurrence of eye disease carriers and sex or the level of inbreeding was also tested. A significant relationship (P < 0.01) was found between inbreeding and the number of animals genetically tested for PLL eye disease. The effect of sex or the level of inbreeding on the eye disease carrier status was non-significant (P > 0.05). However, in some inbred animals the status of the eye disease carrier could be connected with inbreeding, although this needs further research. We found that most of the dogs had related parents and genetic defects. We also found that the breeders often used related dogs, which reduced the genetic diversity of the group and caused hereditary diseases. We suggest that Chinese Crested dog breeders be more open about publishing DNA-test results, which is fundamental for the health of the breed.