Figure 7.

Strain-by-O₃ exposure coefficients for gene expression separate strains by their gene expression responses. PCA was performed with the matrix of strain-by-O₃ exposure coefficients. Each point on the graph represents the first two principal components for a single gene (that has six coefficients, one per strain) and the loadings represent the gene expression characteristic for each strain. Symbols for the top 40 genes contributing to strain loadings are labeled, where those mentioned in the text are royal blue. B6, C57B/6J; O₃, ozone; PCA, principal components analysis.