Use of microsatellites for genetic variation and inbreeding analysis in Sarda sheep flocks of central Italy

A set of 11 polymorphic microsatellites has been used to assess the distribution of genetic variability in 17 flocks of the Sarda sheep breed in the Viterbo province, located in central Italy. The suitability of samples size and number of loci analysed were tested using a bootstrap procedure. The data obtained were used to estimate the genetic diversity within and among flocks, and to test the presence of inbreeding within flocks. To study the genetic relationship among flocks, a principal component analysis based on Nei standard distances was performed. The results of genetic analysis show a significant excess of homozygotes in some of the flocks. The use of genetic data for maximum likelihood tests of assignment is investigated in order to establish suitable breeding policies. This research represents a case study for the development of mating strategies suitable for incrementing genetic variability within flocks that can be applied in other domestic species showing similar breeding problems (goat, buffalo and small populations of cattle).