The distribution of gene expression levels of tested reference genes in pooled C
values. Data obtained from immature (N1), mature (N14), chronic hyperoxia (Hyper14), and chronic hypoxia (Hypo14) treated rat CB. Top panel: PCR amplicons from all tested reference genes were detected on 1.5% agarose gel as single band and correct size of PCR product. Bottom panel: CT values for each reference gene are shown as medians (line in box), means (asterisks), 25 to 75 percentile (boxes), and 1 to 99 percentile ranges (whiskers).