The presence of abundant non-exonic RNAs in introns and intergenic regions in human cells. Chromosomal locations and gene regions that display different patterns of intronic or intergenic expression are shown in panels A-D. For each region, the chromosome, annotated gene and strand are shown at the bottom with annotated exons represented by boxes. Above the exons, chromosomal positions based on the University of California Santa Cruz genes and the hg18 version of the genome are shown. The source of the sample RNA (K562, liver or brain) and the type of RNA preparation (RiboMinus or polyA selected) are shown next to the Y-axis. Examples of loci producing little or large amounts of intronic RNAs are shown in panels A and B. Examples of very long intergenic transcribed regions are shown in panels C and D. The Y axis show the density of reads per each genomic base overlapped by at least one read in reads per 10 million of non-ribosomal, non-mitochondrial reads.