Genetic characterization of two sheep breeds from Southern Italy by STR markers

Altamurana and Leccese are triple-purpose sheep breeds from Southern Italy that suffered in recent years a marked population size reduction. Aim of this work was to evaluate the level of within and among-breed genetic variability, as a contribution in conservation decisions. In the whole, 182 animals were typed for 19 STR markers. Data analysis was carried out by the software Arlequin. The mean number of alleles per marker was 11.3 (range 4 to 17). Several “private” alleles were observed, mainly in Leccese. Significant (P < 0.01) deviation from Hardy-Weinberg proportions was present for some markers, with excess of homozygous genotypes. More than 50% of all pair-wise marker comparisons showed gametic unbalance in both breeds. Allele-sharing similarities were 0.369 and 0.317 within Altamurana and Leccese, respectively, whereas it was 0.298 between breeds, indicating a significant level of genetic differentiation; the mean value of FST was 0.044. The breed assignment test allocated all individuals to their true breed of origin, except for one Altamurana and one Leccese individual. The present results may contribute to design a more appropriate management of these genetic resources.