Genomic locations of differentially-expressed miRNAs associated with spermatogenesis arrest. A. Chromosomal distribution of differentially-expressed miRNA genes identified in patients with NOA. 19 up-regulated (hollow bar) and 154 down-regulated miRNAs (solid bar) were located and numbered on each of the chromosomes. B. Chromosomal locations of human mir-17-92 family identified in patients with NOA. The mir-17-92 family consists of three paralogous clusters: the mir-17 cluster (located at chromosome13q31.3), the mir-106a cluster (located at chromosome Xq26.2) and the mir-106b cluster (located at chromosome 7q22.1). Names of the miRNA precursors are written above the boxes. The position of the mature miRNA is indicated by a dark box. The expression levels of 8 members of this family were differentially down-regulated in testicular tissues for NOA patient (gray), while other members show no significant difference in expression levels between normal and infertile men (white).