Small-RNA libraries. (A) Distribution of the 5 most abundant miRs in the T lymphoid subsets. The sequencing frequency of each miR is shown as the percentage of the total number of known miRs isolated from each T-cell population. Percentages in parentheses on the x-axis report the coverage of each library, estimated by bootstrap analysis as described by Basso et al.²⁰  (B) Top 15 up-regulated and 10 down-regulated miRs in peripheral CD4⁺ and CD8⁺ T lymphocytes compared with DP thymocytes, based on the sequencing data (P < .05; Fisher Exact Test). Histograms report the relative frequency of each miR in the 3 libraries. The value of miR frequency in the DP population was set to 1. (C) miRs consistently regulated during T-cell maturation after the DP stage, identified by comparing data from miR microarrays and small-RNA libraries. The table reports the 18 miRs found to be concordantly regulated in the comparison of SP vs DP thymocytes (from microarrays) and mature T lymphocytes vs DP (from small-RNA libraries).