Method used to calculate the expression context conservation between gn_A and gn_B. Genes gn_A and gn_B are the query genes in species A and species B, respectively. First, the correlation between the expression levels of the query gene and all 1-1 orthologs over multiple microarray experiments was calculated in both species (a; uncentered correlation). The resulting expression correlation values were correlated between the two species (b; Pearson's correlation), yielding the expression context conservation between gn_A and gn_B. For an unambiguous comparison between species, we only analyze the expression correlation values of the studied genes with the 1-1 orthologs.