Genetic characterisation of CSN2 gene in Girgentana goat breed

Abstract

Among calcium sensitive caseins, β-casein is the most abundant in goat milk, representing up to 50% of total casein content. The goat <em>β-casein</em> locus has been widely investigated and at least ten alleles have been identified in different goat breeds. The aim of this work was to investigate the polymorphisms of <em>β-casein</em> gene in <em>Girgentana</em> dairy goat breed in order to assess the genotype distribution and evaluate how frequencies have changed during the last 10 years, as genotype is known to influence technological and nutritional milk properties. Sequencing analysis and alignment of the obtained sequences of <em>β-casein</em> exon 7, showed the presence of C, C1, and A strong alleles, and 0' null allele, with frequencies of 0.597, 0.326, 0.023, and 0.054, respectively. Seven genotypic classes were found in <em>Girgentana</em> goat breed and the most frequent genotype was CC1 (0.423) followed by CC (0.326), C1C1 (0.110), and C0' (0.096). No AA nor 0'0' homozygous individuals were found. The presence of strong alleles at <em>CSN2</em> gene in <em>Girgentana</em> goat breed could be useful for the production of milk with high protein content and good cheese-making properties. Moreover, food business operators should consider the possibility of reviving interest in <em>Girgentana</em> goat milk using weak and null genotypes at <em>CSN2</em> locus to make peculiar food products, such as drinking milk.