Figure 1

Tissue-specific positional preference of poly(A) site usage. (a) Tissue-specific positional preference of type II genes. (b) Tissue-specific positional preference of type III genes. Distance to the median was calculated as (observed usage - median usage)/median usage. Only tissues with significant p values (<0.05, Chi-squared test) are shown here. 2F, 2M, and 2L are the poly(A) sites closest to the 5' end, middle, and closest to the 3' end in a type II gene, respectively. 3U and 3D are poly(A) sites located upstream of the exon closest to the 3' end and poly(A) sites in the exon closest to the 3' end in a type III gene, respectively.