The project was initiated by German and Swiss Newfoundland breeders, which were aware that SAS is a problem in the European or even world population of this breed. Both clubs have a strong exchange of animals and a close informal exchange of information. Their idea was to support the University of Berne (Institute for Genetics) and the SHL to develop a gene test for SAS, which can then be used by breeders to exclude SAS carriers from breeding. As knowledge about the genetic background of SAS is scarce in any breed or species, it has to be clarified in a first step in order to develop the optimal tool for breeders to breed against SAS.
Therefore, the aim of the first step of this project is to estimate the extent of the genetic component (heritability) of SAS and the probable inheritance mode. The results will allow assessing the options for and possible extent of breeding against SAS. If the results show a moderate or high heritability and the inheritance mode is polygenic, breeding against SAS with the help of breeding value estimation combined with cardiac examinations is the most efficient option for breeders to reduce the frequency of dogs affected by SAS. Breeding values will allow to choose the optimum parents in order to reduce the risk of puppies having SAS (= breeding value) to a minimum. Breeding values can be estimated for all animals in a population and their progeny as long as they are related to one or more animals with a SAS diagnosis. Thus, not all animals used for breeding do need an examination with a cardiologist and litters with high risk of having SAS can be avoided. The breeders initiating the project and their breeding organizations will be advised about breeding against SAS with the use of breeding values.
If the inheritance mode is most probably monogenic or mixed (main gene with additional polygenic effects), it is planned to continue the project on molecular bases. Dogs with and without SAS will be genotyped on a chip (SNP markers) followed by fine mapping. Once the SAS causing gene(s) are localized, a gene test for SAS can be developed. Development of a SAS gene test will be done at the Institute of Genetics, University of Berne. With a gene test, breeding against SAS can be done much more efficient than today, extensive examinations stressful for the dog can be avoided, SAS can be diagnosed earlier and treated at an early stage, which may increase life expectancy of affected dogs. Development of a gene test and its funding will be initiated when the results show a monogenic or mixed inheritance mode.
The results of this first step will help to decide on tools for the Swiss/German breeders to avoid the breeding of SAS affected dogs, which on mid to long term will reduce the occurrence of SAS in the Newfoundland and Landseer population.
If a gene test can be developed, it will be done in close collaboration with the Swiss (and German) Newfoundland breeders’ organization as well as the Swiss cardiologists. They all agreed to support the collection of blood samples necessary for the genotyping.
General impact of the results of the first project step: The extend of the heritability and the inheritance mode can be assed for the first time in a dog breed, which may enhance to define the genetic cause of SAS in other dog breeds with high occurrences of SAS or even species. Heavy suffering of animals from this often lethal disease can hopefully be reduced or avoided in the future.
