Fig. 3

The differentially expressed genes associated with susceptibility of subclinical S. aureus mastitis. a Cluster analysis of differentially expressed genes between S. aureus mastitis and healthy cows. From gene expression data, 25 up-regulated and 36 down-regulated genes were identified between S. aureus mastitis cows (SS1, SS3 and SS4) and healthy cows (SH2, SH5 and SH6). Normalized intensity values of genes (columns) were ordered using Centroid Spearman Rank Correlation and hierarchical clustering in Cluster3.0 software. The dendrogram showed the similarity (distance) of mRNA expression levels and was divided into sub-trees as distinguished from different colors. Arrays (rows) were grouped by six different individuals. Yellow and blue colors reflect the high and low expression intensities, respectively. b GO analysis of differentially expressed genes. Genes were grouped by cell component, molecular function and biological process based on the bovine GO annotation information. Gene numbers and percentages (on log scale) are listed for each category