Figure 1.

(A) Box plot of gene expressions in human control nucleus pulposus tissue and degenerative nucleus pulposus tissue before normalization. (B) Box plot of gene expressions in human control nucleus pulposus tissue and degenerative nucleus pulposus tissue after normalization. The X axis represents samples and the Y axis represents expression level of genes after log2-transformation. The black line in the center is the median of expression value, and consistent distribution implies a good normalization.