SRR3402126

This is a small-RNA (miRNA-Seq) library from mouse, sequenced on a HiSeq 2500, and it fails QC decisively at 18/100 (grade F). The grade is driven down overwhelmingly by base-call quality: only 31.4% of bases reach Q30 and the mean base quality is 14.3 (roughly a 1-in-25 error rate), both scoring 0/100, which means base calls are unreliable enough to compromise the precise sequence matching that miRNA quantification depends on, and the 70% duplication rate further erodes library complexity. The one bright spot is essentially zero adapter contamination, but for a miRNA library — where short inserts normally produce heavy, expected adapter read-through — a 0% adapter figure is itself suspicious and may indicate the small-RNA inserts were not properly captured or the metric was computed on already-trimmed reads. With an evidence_strength of 1, all four scoring metrics were directly measured, so this poor verdict is not provisional — though I'd recommend reusing this dataset only with strong caution, if at all, given that low base quality fundamentally limits confident miRNA identification and expression estimates.