Quantification of miR copy number is used to determine functional levels of expression in HSPC subsets.

<p>a) copy number per cell was determined in the GMP subset for 15 representative miRs, and plotted against normalized array value. Regression analysis was used to infer the relationship between the two values (best-fit line appears in red), and from this we estimated the array value above which we are 95% certain that a miR with >100 copies per cell would appear. That is, we estimated a one-sided 95% confidence interval of array values for miRs with 100 copies per cell or greater. Thus, miRs with >100 copies per cell have array values over the estimated cut-off (6.25) with significance level p<0.05. b) number of individual miRs c) number of miR families represented d) number of mRNAs expressed in each HSPC population, as determined by having at least one probe significantly higher than “dark” control probes (p<0.01), as determined by an unpaired t-test comparing replicates of a unique probe's values to all dark control probes.