Analysis of the genetic diversity between Gentile di Puglia, Sopravissana and Sarda sheep breeds using microsatellite markers

Two Italian sheep breeds - Gentile di Puglia and Sopravissana - have undergone a consistent decline in numbers and have been widely substituted by the Sarda breed, which gives higher milk yield. With the aim to provide a basis for conservation decisions, the genetic variability of the three breeds was investigated in this study. DNA of 60 animals was PCR amplified at the following microsatellite loci: CSSM43, CSSM47, CSSM60, TGLA110, TGLA122, TGLA126, TGLA377, ETH3, ETH10, ETH225, NRAMP1, OARCP20 and SPS115. Allele frequencies, gene diversity and genetic distances were calculated. The highest differences in allele frequencies were found at the following loci: TGLA377, TGLA122, NRAMP1, OARCP20 and ETH3, while at the other loci the most frequent alleles were the same. The average inbreeding rate was 0.156 in the Gentile di Puglia, 0.158 in the Sopravissana and 0.137 in the Sarda. Average gene diversity of the analysed microsatellites was 0.59. Genetic distance between Gentile di Puglia and Sopravissana (0,081) indicates moderate differentiation; distances between the Sarda and the endangered breeds - 0.111 from the Gentile di Puglia and 0.107 from the Sopravissana - indicate a medium-high differentiation rate. The disappearance of the two less productive breeds would entail a consistent loss of genetic diversity. The inbreeding values are low enough to allow the implementation of sound conservation programmes.