We further tested MixMir on a published set of adrenal cortex Dicer - KO experiments , performed by Krill et al . ( 25 ) . The authors found that while mouse embryos with Dicer - KO adrenal cortex cells developed normally up to E14.5 , at E18.5 they experienced total adrenal cortex failure . In all they found 16 miRNAs that were downregulated in the adrenal cortex of both E15.5 and E16.5 mice , including miR-34c , miR-21 , miR-10a and let-7d , which play a role in tumorigenesis among other functions ( 25 ) . They also presented lists of miRNAs specifically downregulated at each stage . We analyzed the mRNA microarray expression data ( see Methods ) from both E15.5 and E16.5 embryos using the linear model , miReduce , Sylamer , cWords and MixMir . When compared to the miRNAs that are downregulated at both E15.5 and E16.5 , we found that most methods were able to find either an exact or offset seed match to let-7d either as the first or second motif returned , with the exception of the linear model , which performed worse . Overall , MixMir ranked true miRNA seeds higher than the other methods in both E15.5 and E16.5 datasets ( Table 5 ) . Most notably , MixMir found both miR-34b and miR-34c in the top ranked motifs at E15.5 , which no other method was able to do . We also performed a separate analysis of motif ranks and miRNA matches for E15.5 and E16.5 separately , as some miRNAs were found to be significantly downregulated at one stage and not at another -- namely , there were more such miRNAs at E16.5 , as expected . We found sim - ilar results in this analysis , in particular that MixMir consistently found biologically significant miRNAs , with performance comparable to miReduce for both time points . cWords and the linear model were comparable for E16.5 only ( Supplementary Table S8 ) .