Goat milk, cheese and yoghurt offer an alternative to cow milk products. In Sicilyone of the important goat breeds reared is the Girgentana. Traditionally the milkfrom Girgentana goats was used for nourishment of infants and elderly. Recently, theGirgentana breed has been in decline. This of concern, as the Girgentana may carryunique milk protein genetic variants. If health benefits of Girgentana goat milk isproven, then increasing production from this population will be of great interest. Themost abundant proteins in goat milk, as in other milks, are the caseins, αS1-, β-, αS2-and κ-casein, coded by the loci CSN1S1, CSN2, CSN1S2 and CSN3 respectively. Inother goat breeds, the casein loci have been found to be highly polymorphic, and anumber of genetic variants of the casein genes that affect milk production traits havebeen described. The aim of this study was to quantify the variation of casein lociwithin the Girgentana breed, and additionally to determine if there was anyagreement between DNA polymorphism and isoelectrofocusing (IEF) proteinexpression of αS1. Forty individuals including goats and bucks were genotyped for 9SNPs and one deletion (exon 9) in CSN1S1, 7 SNPs in CSN2, 3 SNPs in CSN1S2and 13 SNPs in CSN3. Genotypes for the deletion in exon 9 were in very goodagreement with the IEF, results; goats that were homozygous for this deletion had noor very low levels of αS1 expression, goats that were heterozygous had intermediatelevels of expression, and goats that were homozygous for the non deletion allele hadfull αS1 expression. For each casein, haplotypes of the SNP genotypes wereconstructed. There were a limited number of haplotypes within each casein locus; 6for CSN1S1 and CSN2, 3 for CSN1S2, and 7 for CSN3. The limited number ofhaplotypes indicates strong linkage disequilibrium between SNPs within each locus.Future work will determine if the haplotypes have significant effects on health andproduction traits, and their potential for use in marker assisted selection.
|Number of pages||1|
|Publication status||Published - 2006|