Figure 1. Impact of sex on C. burnetii infection.

Male and female mice were infected with C. burnetii for 24 hours. Transcriptional responses were assessed by microarray. A, The impacts of sex and infection on gene expression were analyzed by principal component analysis using R. Each axis distance represents the amount of variance in gene expression explained by the corresponding factor (sex or infection). B, Hierarchical clustering analysis was used to classify selected up-regulated and down-regulated genes in four clusters: sex-independent genes, male-dependent genes, female-dependent genes and genes inversely modulated in males and females (red vertical bar).