Tissue by tissue comparison. This figure shows the total number of genes with a significant increase in gene expression between the row tissue (left) and the column tissue (bottom). For the genes reported in each cell, there is more transcriptional activity in the column tissue than the row tissue. For example, there are 7,298 genes that have a higher transcriptional activity in young leaf than in flower. Also, there are 10,262 genes that have a higher transcriptional activity in flower than in young leaf. These two statements are mutually exclusive and therefore each cell represents a different set of genes.