cDNA microarray transcriptional profiling indicates differential gene expression between neonatal and adult articular cartilage. (a) Histomorphometric comparison of isotropic articular cartilage structure in the equine neonate and the anisotropic structure in adults. (b) A p-value histogram of differentially expressed transcripts from the 9,367 element equine-specific cDNA microarray demonstrates that just under 7% of the clones had significance at p < 0.01. (c) A volcano plot of the neonatal versus adult comparison; points above the horizontal black line are transcripts demonstrating differential expression with a significance of p < 0.01. The two vertical black lines correspond to 2-fold up- and down-regulation. Degree of statistical significance is displayed along the vertical axis and expression fold change along the horizontal axis.