Microarray analysis. Microarrays show gene variants are conserved across unrelated lineages. Genes are listed in order by name and by their annotated gene number prefixed with the strain that was used as the template for the PCR probe on the microarray (R, MRSA252; N, N315; 8, 8325; M, MW2; U, Mu50). A black box indicates the gene or gene variant is present in that lineage. '*' indicates the genome of a strain from this lineage has been sequenced. '+' indicates ORFs from this lineage are included on the 7 strain microarray. C indicates community associated MRSA were included, and H indicates hospital associated MRSA were included. Strains from the following hosts were included: h, human, b, bovine, e, equine, p, pig. 'v' denotes a PCR product designed to a specific variant region. 'u' indicates variation in gene distribution for that lineage.