Genome-wide characterization of a local heeling dog population from Northern-Apennines

Over the centuries, dogs accompanied humans as they moved seasonally in search of grazing land for their livestock in the practice of transhumance. The subject of this study is a population of heeling dogs, which has been identified in the Apennine area stretching from the Tuscan-Romagna Apennines to the Monte Vettore massif. These dogs, to which we’ll refer as Apennine heeling dogs, have been reared by various sedentary and transhumant shepherds, who have selected individuals with homogenous physical and behavioural characteristics. The population is morphologically characterized by a long, trotter-like body, a dolichocephalic head with a pronounced stop, a broad and strong muzzle, erect ears, round eyes, a muscular neck, thick and adherent skin, strong limbs, powerful muscles, a low-set tail, and a rough coat with various colors and patterns. The aim of this study is the genomic characterization of the population and the investigation on his relations with other shepherd and heeling dog breeds both from neighboring areas and the international context. To achieve our goal we sampled 16 dogs with recorded pastoral ancestry, a group of 6 dogs from the same area and with similar morphological features, but with uncertain ancestry. The samples have been genotyped through the Embark™ SNP chip which is based on the Illumina CanineHD™ BeadChip. Our samples have been merged with the consortial dataset of the LUPA project. Additionally we retrieved genotypes from other 9 heeling and shepherd breeds. Genetic diversity indices (Ne, He, Ho, and FROH) have been calculated. Then, the genetic structure of the population has been assessed through ADMIXTURE, TREEMIX and an MDS analysis. Our results showed genetic diversity indices suggesting the necessity of management of inbreeding and genetic drift. The results of the three genetic structure analyses are consistent and indicate that the population possesses a distinct genomic identity. Furthermore, we observed a shared ancestry between the investigated population and the group of six dogs originating from the same area. The results of this study emphasise the significance of utilising genomic data in conjunction with morphological observations for the characterisation of dog breeds. Furthermore, this approach may assist in the management of local dog populations' genetics by identifying animals that can be used to increase the breeding stock using molecular information.