Experimental design and clustering analysis of the gene expression pattern in O. taurus day 1 pupa. A. Microarray experimental design. The pupal tissues used are indicated in the upper panel and the microarray hybridizations are illustrated in the lower panel. Head horn (head) is labeled yellow, thoracic horn (thorax) is labeled pink, legs are labeled blue, and abdominal epithelium (abdomen) is labeled white. B. Hierarchical clustering of differentially expressed genes. 1,367 spots were clustered based on their M-values when compared to abdominal epithelium. Each row represents a single spot and each column represents the sample. Relative magnitude of gene expression level is indicated by color brightness; red indicates enriched compared to abdominal epithelium whereas green indicates depleted relative to abdominal epithelium. M-values ranged from -4.85 to 4.12. Bootstrap values were obtained after 5000 trials. Branch lengths represent relative distances between the samples.