Chromosome pairs from which genes are found together in one co-expression cluster. Square colours correspond to the frequency of observation of genes from a pair of chromosomes within the same co-expression cluster. The upper triangle colours indicate the number of standard deviations between co-expression gene pair counts for real and randomised data, the lower triangle – p-value (0.05 threshold for each one-tailed test). Chromosome order is by chromosome size (top) or chromosome gene density (bottom). Symatlas data (left), NeMo data (right).