Hierarchical clustering of stamen microarray samples. Hierarchical clustering of 15 rice stamen microarray samples (PDNN) using 4234 probe sets only present in stamen samples. Left is clustering using PDNN preprocessed data with original PM, while right using PDNN preprocessed data with adjusted PM. Before adjustment, sample Stamen 3.1 is far away from the other two samples of stage 3. After adjustment, it is classified to be with sample Stamen 3.2.