Genetic variability of the Gentile di Puglia sheep breed based on microsatellite polymorphism

The aim of the present study was to estimate the genetic variability of the Gentile di Puglia sheep breed by using microsatellite markers, to provide information useful for conservation. The DNA of 82 animals, belonging to 6 different farms, was analyzed at 19 microsatellite loci. The number of alleles, allele fre- quencies, deviations from Hardy-Weinberg proportions, linkage disequilibrium among loci, genetic similarity, genetic distances, and molecular coancestry-based pa- rameters were calculated. Seventeen out of 19 micro- satellites showed heterozygote deficiency in the whole population, although only 4 (OarAE129, ILSTS28, ILSTS5, MAF33) showed significant deviations from Hardy-Weinberg proportions (P < 0.01). The genetic similarity (an index of allele sharing among individu- als) within the whole population was low (0.318), and the average number of alleles per locus was quite high (9.68). The results obtained highlighted a population presenting both a deficiency of heterozygotes and great genetic variability. These results suggest that stratifica- tion of the breed in subpopulations, probably derived from different farm management in each herd, led to a population characterized by great genetic diversity among different herds and by great similarity within each herd. Moreover, in the past, Gentile di Puglia sheep have undergone a strong numeric decline, involv- ing genetic drift effects and considerable consanguinity within the breed.