Impact of CSN1S1 polymorphism on mammary transcriptome of lactating goats

Genetic (animal species, breed and genotype) has a considerable effect on milk composition. In particular, goats present a remarkable polymorphism at the alpha-S1-casein (CSN1S1) locus which results in large differences in milk protein content and indirectly in milk fat content and its fatty acids composition. In order to decipher the mammary metabolic pathways involved, we examined the effect of CSN1S1 polymorphism on the expression of 8,379 genes in caprine mammary gland using a bovine oligonucleotide microarray. Six lactating goats fed ad libitum were assigned to 2 groups based on their genotype at the CSN1S1 locus: High vs. Low genotype goats carrying, respectively, two reference alleles associated with high CSN1S1 synthesis and two defective alleles associated with low CSN1S1 synthesis. Keywords: Genotype comparison 6 slides were performed for a total of 3 independent comparisons (Comp1, Comp2, Comp3): each microarray was co-hybridized with one High CSN1S1 genotype goat sample and one Low CSN1S1 genotype goat sample; each hybridization was repeated in a dye-swap manner for a total of 4 spots per oligonucleotide (2 intra- and 2 inter-slides).