CT values were calculated for all miRNA PCR reactions at a uniform threshold of absorbance across all experiments and controlled to CT values for the endogenous reference (snoRNA234 in mouse-only experiments, U6 in human and cross-species comparisons). The expression of individual miRNAs is presented as relative snoRNA234 units in order to convert the ΔCT value for each miRNA into a relative molar measure (calculated as 2ΔCT).