Genomic landscape of miRNA genes. (A) The distribution of miRNA genes and clusters across the D. melanogaster genome, with newly identified miRNAs indicated (red). Euchromatic portions of the genome are drawn to scale, with (+) strand annotations marked above each chromosome and (−) strand annotations marked below. MicroRNA gene clusters, listed together (with gene numbers separated by slashes), were each defined as series of miRNA loci on the same strand of a given chromosome with no intervening gaps >10 kb. (B) Genomic arrangement and conservation of members of the mir-972∼979 cluster. Detection of an ortholog in the specified species is indicated (black box). (C) Genomic arrangement of the mir-310 cluster. Expression profiles among the constituent miRNAs of each labeled subcluster indicate that the two subclusters were expressed independently (Fig. 6E).
