Gene expression profiles of monkey ovaries of different ages. (a) Log-log scatter plot analysis between groups of different ages. It shows good quality of microarray data; the red and green dots indicate upregulated and downregulated genes, respectively. (b) Hierarchical cluster of differentially expressed genes in old (O), middle-aged (M), and young (Y) groups. The expression level of each gene is standardized to a mean value of 0 and standard deviation (SD) of 1. The mean value is represented by black, gene expression above the mean level is represented by red, and expression below the mean is represented by green. The intensity of the pseudocolor reflects the number of SDs from the mean, as indicated in key at left. 1–3: animals 1–3 in each group.