a. MeRIP enrichment (upper) and expression level (lower) of m(6)A-negative (blue) and positive (orange) intronic regions in liver and stomach. Both the enrichment of IPed versus input RNA and the expression level are normalized against GAPDH. MeRIP-qPCR and qPCR were performed once with two technical replicates obtained and shown (see source data in Supplementary Table 5). b. Sequence logo and p value of deduced consensus motif of 81981 intronic m(6)As with strand information. Binomial distribution test (see methods for details). c. Ratio of uniquely mapped reads in intronic regions. Biologically independent samples n=3, 3, 3, 3, 2, 2, 3, 2 in brain, heart, kidney, liver, lung, muscle, placenta and stomach, respectively (see source data in Supplementary Table 5). d. Fraction of intronic m(6)As in each tissue determined in a rigorously way as described in methods. e. Histogram of completed splicing index (coSI) values for internal exon in each tissue.