The 22-nt motif associated with the phased 24-mer clusters. (A) The phased and unphased small RNAs that comprise a representative phased 24-mer cluster are shown, and the 22-nt motif is shown by the arrow at the top, below “motif.” The polarity of the small RNAs is indicated by the arrows, and the number of times the small RNA was sequenced is indicated above the arrow. This 24-mer cluster is located at chr11:22601855..22602293. The probability that this cluster is phased by chance alone is 6.8 × 10−15, and the probability that the indicated motif matches the consensus by chance alone is 1.4 × 10−9. (B) The probability of a nucleotide occurring at specific positions of the motif is shown in the top matrix, and the consensus sequence of the motif is shown below the matrix. The letter “a” represents a probability of 100%. (C) The positions of the 27 motifs that are offset 12 nt from the phase of the phased 24-mer clusters are shown.
