Co-expression decreases with increasing distance (Inset: blow-up of 0-10 intervening genes). Co-expression is strongest for direct neighbours (distance = 0), drops quickly up to 2 intervening genes, and then slowly decreases until it reaches average values for non-neighbours (dashed line) at very large distances. Co-expression of direct neighbours is significantly higher than for random pairs regardless of gene orientations (Table 1), and co-expression is higher than for random pairs up to 100 intervening genes (P < 0.02 for each distance bin). Co-expression is measured as Pearson's correlation coefficient of gene expression vectors across experiments. Distance is measured as the number of intervening genes along the chromosome.
Chen et al. BMC Genomics 2010 11:178 doi:10.1186/1471-2164-11-178