Categories of cDNA clones derived from immunoprecipitated small RNA of HeLa cells. A: Composition of small RNA cDNA clones. The composition of cDNA clones is shown in a circle graph. Almost all of the recovered cDNA was miRNA (94%), while the remainder was rRNA and tRNA clones (3% and 2%). 'Others' indicates the cDNA clones with hits in the genomic sequence. B: Contents of miRNA clones. Each miRNA clone was deduced by BLAST search. The y-axis indicates number of clones of each miRNA species.