Unsupervised hierarchical clustering of mixed and individual profiles. Shown is a dendrogram of nearest neighbor analysis of 34 MuscleChip expression profiles including both individual and mixed samples. Mixed samples cluster as very highly related samples, even though different regions of the component biopsies were used to generate the duplicates. Importantly, the mixed DMD profiles cluster more closely with mixed normal controls than with individual DMD patient profiles. This data suggests that intra-patient (tissue heterogeneity) and inter-patient (SNP noise) can be significant sources of experimental variability.