Variability of the caprine whey protein genes and their association with milk yield, composition and renneting properties in the Sarda breed. 1. The LALBA gene

Abstract

The 5′ flanking region and 3′ UTR of the caprine LALBA gene were analysed by SSCP and sequencing. A total of nine SNPs were detected: three in the promoter region, two were synonymous coding SNPs at exon-1, and four SNPs were in exon-4, within the 3′UTR. The nucleotide changes located in the promoter region (c.−358T>C, c.−163G>A, c.−121T>G) were genotyped by SSCP in 263 Sarda goats to evaluate their possible effect on milk yield, composition and renneting properties. We observed an effect of the three SNPs on milk yield and lactose content. Genotypes TT and CT at c.−358T>C (P < 0·001) and genotypes AG and GG at c.−163G>A (P < 0·01) were characterised by higher lactose contents, while c.−358CC and c.−163AA showed the lower milk yield (P < 0·01). SNPs c.−358T>C and c.−121T>G were part of transcription factors binding sites, potentially involved in modulating the LALBA gene expression. The LALBA genotype affected renneting properties (P < 0·001), as heterozygotes c.−358CT and c.−163GA were characterised by delayed rennet coagulation time and curd firming time and the lowest value of curd firmness. The present investigation increases the panel of SNPs and adds new information about the effects of the caprine LALBA gene polymorphism.