Genome content of S. aureus strains D30 and 930918-3. The figure illustrates the occurrence of genes in strains D30 (panel A) and strain 930918-3 (panel B). We also depict genes belonging to core, variable and unique gene complements of the two strains in their respective panels. The genes are represented in the array where the rows are named R1 through R72 and the columns are named C1 through C86. Each array element indexes a single gene. For example the index R1:C1, or simply (1:1) represents the first gene and (1:86) represents gene 86 and so forth. The number of genes in D30 and 930918-3 are calculated to be 2714 and 2879 respectively. The dark blue dots represent the core genome of S. aureus, the red dots represent the ORFs from the variable genome that are shared between the strains. The light blue dots represent ORFs unique to each strain with respect to the other and the black dots represent absence. A complete list of gene IDs (this study) and matrix positions are provided in Additional file 1, wherein the information is similarly color coded for the ease of identification.