Correlation of gene expression with the levels of nucleosomal occupancy among var genes. A. Microarray results of nucleosome occupancy in representative var genes. The var gene PFC0005w displayed the lowest nucleosomal occupancy of all var gene, whereas PFD0630c and PFD0635c had the next lowest nucleosomal occupancy. PF07_0051 (internal) and PF11_0521 (subtelomeric) represent var genes with higher nucleosome occupancy. The x-axis indicates the base pair position on the chromosome. B. The relative expression level (red) and nucleosomal occupancy level (blue) of individual var genes in an unselected parasite population. The var genes' expression levels had a inverse correlation with the levels of nucleosomal enrichment (Pearson correlation R2 > 0.90). C. Relative nucleosomal occupancy of var2CSA gene in CSA-unselected (silent) versus CSA-selected (active) parasites. Relative nucleosome enrichment levels for var2CSA-off versus var2CSA-on parasites were determined during three developmental stages. The locations of the primers to map these genes are marked with A to H in Figure 6A.