Sample correlation matrix and hierarchical cluster analysis of gene expression profiles after DNA injection. A sample correlation matrix (upper panel) between DNA injected or non-injected groups was built on the original two-way hierarchical unsupervised clustering. Red indicates high correlation and blue represents little correlation. In the original hierarchical unsupervised clustering (lower panel) the columns indicate the treatment condition and the rows indicate the individual genes, listed with their Genbank number. Increases and decreases in mRNA expression levels are represented by shades of red and blue.