The Fonni’s Dog as a Means to Define ‘Breed’ and Inform Inter-Species Island Colonization

The domestic dog species includes over 300 closed breeding populations world-wide. Each breed has a unique ancestral history, influenced via artificial selection, to produce distinguishing physical, aesthetic, and behavioral characteristics. Recent research has characterized the resultant patterns of genetic homozygosity within >80 of these breeds, revealing an interplay of breed-specific levels of homozygosity and the degree of individual dog variation within each breed. The Fonni’s Dog is a little-known dog breed endemic to the Italian island of Sardinia. Genomic demography, relative to 27 additional dog breeds from the Mediterranean region, has been used to classify the Fonni’s Dog as a genetically independent population of dogs that displays the expected molecular characteristics of a pure breed. Comparison of the Fonni’s Dog to geographically relevant breeds determines the ancestral contributions to the breed formation, and the involvement of the Fonni’s Dog in the development of other Mediterranean dog breeds. Further, intriguing parallels are drawn between the genetic ancestry of the Fonni’s Dog and a predicted model of human colonization of the islands of the Mediterranean Sea.