Finding the EIC Gene
Our work at the University of Minnesota identified the chromosomal location of the EIC gene during a “genome scan” with “DNA markers”. In this genome scan DNA markers that are present at known and unique locations on each of the dog chromosomes were used to identify specific patterns of inheritance of these chromosomal segments in DNA samples from hundreds of dogs. By examining the inheritance pattern of these DNA markers in multi-generation Labrador Retriever pedigrees where EIC was present, we eventually identified which chromosome contained the EIC gene.
The DNA of several candidate genes in this small chromosomal region that are involved in muscle and nerve metabolism and function was sequenced, and a mutation in one gene that is very strongly associated with EIC was identified. This is a compelling candidate causal mutation for EIC due to the critical role of the protein encoded by this “EIC gene” in synaptic communication between nerves in the central nervous system.
The discovery of the EIC gene and its mutation will provide breeders and veterinarians with a non-invasive test for definitive diagnosis, and a selection method for designing matings that can limit the production of affected dogs.