
Image reproduced from PloS Genet. (Baranowska et al., 2009).
Mutations in human mitochondrial DNA (mtDNA) can cause diseases that affect a wide variety of organ systems, with the greatest pathogenic effects seen in energy-consuming tissues such as muscle. A research group from Sweden discovered a naturally occurring neurological disease in golden retrievers, sensory ataxic neuropathy (SAN), which is caused by a deletion of one base in the mitochondrial tRNATyr gene. The careful pedigree records of the golden retriever breed allowed the researchers to identify a common ancestor of all SAN-affected dogs, traced back to the 1970s. Identification of this gene will not only allow elimination of this disease in golden retrievers through selective breeding, but it also establishes a new animal model in which to study the characteristics of myopathy associated with tRNATyr mutation in humans.