Post-pubertal, sexually dimorphic gene expression patterns in spleen. Shown is a data visualization of gender-specific gene expression patterns in normal mouse spleen. Six C57BL/6 mouse spleens from each sex at the pre-pubertal (3–4 weeks), pubertal (6–9 weeks) and post-pubertal (24–28 weeks) stages (a total of 36 mice) were analyzed using high-density oligonucleotide arrays. A hierarchical clustering algorithm was applied to group genes based on the similarities in gene expression patterns. The X-axis represents time points (weeks) in female (left) and male (right) mice. The Y-axis represents relative intensity ratios. A: Gene cluster up-regulated in post-pubertal female mice, B: Gene cluster up-regulated in post-pubertal male mice. These clusters were used for subsequent identification of sexually dimorphic immune function pathways.