Correlation for gene expression pattern. Correlation of gene expression patterns for Collagen II and SOX-9: (A) An inverse relationship was observed between the genes expressed and animal weight. (B) Thicker cartilage had low levels of gene expression as compared to thin articular cartilage as depicted by a downward non-linear line in this graph. (C) The upward line in the graph demonstrates that cartilage with less cell count per surface area has low levels of gene expression, possibly due to the low concentration of RNA in the chondrocytes of the articular cartilage. (D) The inverse line in the graph suggests that cartilage with low level of gene expression had greater amounts of GAGs/protein.