Examples of fine-grained tissue specificity. Examples of fine-grained tissue specificity are shown. (a) CAGE tag distribution of a tag cluster located at the 5' end of Ppap2b (tag cluster ID: T04F062B54A0), which is classified as positionally biased. The CAGE tag count at each nucleotide position is displayed as a vertical line. Totals of CAGE tag counts derived from all libraries are shown as all libraries, and two tissues picked from the 22 utilized tissues, liver, and lung are also shown. Arrows within the histograms indicate median locations of transcription initiation. (b) CAGE tag distribution of a tag cluster located at the 5' end of ORF61 (tag cluster ID: T10R04C2E25C), which is classified as regionally biased. The CAGE tag counts of all libraries, embryo, and liver are shown. Gray backgrounds indicate regions with different tissue specificity from the remaining part of the tag cluster. CAGE tag counts in each library and additional information for tag clusters is also accessible from the CAGE Analysis Database . CAGE, cap analysis of gene expression.