Study of β-defensin polymorphisms in Valle del Belice dairy sheep

The aim of this work was to sequence the exons of β-defensin 1 and 2 genes (SBD1 and SBD2) in Valle del Belice dairy sheep in order to identify polymorphisms. The study was conducted on 60 samples from three flocks. Six SNPs were identified: two in SBD1 and four in SBD2. Both genes consist of two exons and one intron. In SBD1 gene, SNPs were found only in the exon 2, whereas in SBD2, SNPs were detected in both exons. In both genes, SNPs were located in the coding regions and in the 3'-UTR. The SNP in SBD2 located at position 1659 determined a change in the protein sequence. Further studies will be necessary to investigate if the amino acid change modifies the biological function of the protein and the association with SCC, in order to use this information in a breeding program for mastitis resistance in Valle del Belice sheep.