Leveraging genomics for modern dog breeding and conservation: the Sicilian Mastiff case study

The Sicilian Mastiff (Mannara dog) is an ancient breed that has been an integral part of Sicilian pastoral life as a livestock guardian. However, unregulated crossbreeding has threatened its genetic integrity. About 100 new individuals are registered in the herdbook annually, bringing the breed head count to around 700. To mitigate extinction risks, conservation efforts resulted in the breed recognition as a native Italian breed by the Italian Kennel Club in March 2023, marking a crucial step towards achieving international recognition. This shift affirms the breed’s distinct lineage and enables structured breeding programs, genetic health screenings, and phenotypic evaluations to preserve its integrity. Here we employ genomic tools, specifically SNPchip-based analyses through MyDogDNA®, to assess the genetic diversity, wellness, and health of the breed by investigating inbreeding levels, hereditary diseases, and breed distinctiveness. As a first survey, we genotyped 22 dogs. The breed’s heterozygosity levels range from 0.24 to 0.42, with the tested group averaging 0.41, indicating moderate genetic variability. Over 250 genetic conditions were screened, identifying three carriers of progressive retinal atrophy (PRCD) and one carrier of adult-onset deafness (intergenic). Further, associations with key phenotypic traits such as coat color, presence of hind dewclaws and ear shape, were also found. Our results offer a preliminary genetic characterization of the breed, contributing to conservation efforts, and will be instrumental toward the Sicilian Mastiff’s official recognition as a historically significant Italian breed.