Genetic characterization of the Bardigiano horse using microsatellite markers

The study was aimed at investigating the genetic structure of the Bardigiano horse and its relationships with the Haflinger, Maremmano and Arabian breeds using 11 microsatellite markers. A total of 94 alleles were detected across the breeds, with a mean of 8.5 alleles per locus and a mean observed heterozygosity of 0.69. Compared to the other breeds, the Bardigiano horse showed quite a high genetic variability, as indicated by the mean number of alleles (7.0 vs 6.1 divided by 7.6) and by the observed heterozygosity (0.72 vs 0.66 divided by 0.71). Moreover, the genotype distributions in the Bardigiano groups of different sex and age were not significantly different. The overall F-ST value showed that the genetic differences among breeds accounted for 7.8% (P=0.001) of the total variation, and the pairwise F-ST values were all significant. The assignment test allocated between 96.8 and 98.9% of the individuals to the population they were collected from, with a mean probability of assignment of about 97% for all breeds, except for the Arabian, where it approached 100%. The results have highlighted that the Bardigiano breed has a high within and between breed variability, which is considerably more than could be expected by looking at its evolution history. This justifies the need for the development of additional breeding strategies to preserve the existing genetic variability.