Format
gene_id in featureData is mainly, RefSeq mRNA, which is supplemented by GenBank ID if RefSeq mRNA is not available. The expressions are two biological replicates: one day after transfection of let-7a and two biological replicates one day after transfection of mock (negative control), respectively. Sample_name in phenoData represents these characteristic features of samples.Source
This comes from experiments described in Takahashi et al. (2009).