The autochthonous agerolese breed: genetic structure at CSN1S1 and CSN3 loci.

This work arises as targets the genetic characterization at CSN1S1 and CSN3 loci, using techniques of molecular biology, of the agerolese cattle, an autochthonous genetic type reared in Campania, which is at risk of extinction.In particular, we proceeded to the identification of the CSN1S1 G and CSN3 B allele carriers, whose choice was dictated by the documented importance of their products (as1???CnG and k??? CnB).The molecular event that characterizes the CSN1S1 G allele is an insertion of a truncated retroposonlike element (LINE) of 371 bp realized between nucleotides 58 and 59 of 19th exon. Consequently, the 19th exon of bovine CSN1S1 G allele appears to be 756 bp long instead of 385 bp[1].The cause of a reduced efficiency of protein synthesis has been hypothesized to be an interaction between the LINE nucleotide sequence and the poly(A) sequence of the mature transcript, with consequent reduction of mRNA stability and its rapid degradation.The mutation responsible for the CSN3 B allele is a nucleotide substitution (GATAsp???GCTAla) at nucleotide 416 of 4th exon. This mutation is located relatively close to several glycosylation sites and probably affects the structure of the protein and glycosylation patterns[2]. It was reported that the CSN1S1 G allele is responsible for a considerable reduction of the content of as1 casein that involves a lower coagulation time and curd firmness of milk compared to that produced by cows bearers of the remaining alleles[3].Similarly, it was shown that the k???CnB variant influences the processes of cheesemaking, giving the milk a better attitude to cheese, with lower clotting times and firming, greater consistency of the curd and higher yield. From the milk obtained by the CSN3 BB cows it can get a higher yield in "Parmigiano Reggiano" equal to ~10%[4] The genomic DNA was extracted from 79 individual samples of bovine blood reared in different farms located in Campania. For the genotyping of CSN1S1 G allele carriers was applied a PCR protocol[1].The genotyping of CSN3 B allele was achieved by means of Hinf I PCR???RFLP[5] Indicating with N the other alleles at CSN1S1 and CSN3 loci, the genotype distribution of investigated population was 74N/N, 5N/G, 0G/G for CSN1S1 with a G allele frequency of 0.03 and 25N/N, 33N/B, 21B/B for CSN3 with a B allele frequency of 0.47 It can be assumed that the evidenced genetic variability at CSN3 locus for the agerolese cattle genetic type plays an important role in the determination of some fundamental parameters, both from the nutritional point of view that technological, for the production and quality of milk and of DOP products derived from it as the historians cheeses "Provolone del Monaco" and "Fior di latte???