The genetic variability of the Podolica cattle breed from the Gargano area. Preliminary results

Abstract

The Podolica cattle breed is autochthonous of Southern Italy and denoted by its particular rusticity. This study presents the preliminary results of the genetic characterization of the Podolica breed using DNA STR markers. A total of 20 microsatellite loci were analysed in 79 individuals reared in the Gargano area. Number of polymorphisms, allele frequencies, deviations from Hardy-Weinberg proportions, linkage disequilibrium between loci and genetic similarities between animals were calculated. The results showed a high deficiency of heterozygotes, the observed mean of heterozygosis being 0.449, whereas the expected mean was 0.766. Many markers showed also deviations from the Hardy-Weinberg proportions and significant linkage disequilibrium between loci. However the genetic similarity within the population was low (0.281) and the average number of alleles per locus was high (10), representing a high genetic variability. In order to explain these results, a stratification of the breed in sub-populations with a high interior genetic homogeneity but markedly differentiated one from each other could be hypothesized; this situation probably derived from nonrandom mating within each herd (consanguinity) and from the lack of exchange of genetic material between the herds. A further study is needed on a wider sample and extending the analysis to FAO-ISAG microsatellite panel in order to confirm this hypothesis. This could eventually provide the information necessary for the correct management of the reproductive schemes and for genomic traceability of meat production.