Correlation coefficients (scatter plot analysis, BeadStudio 3) obtained comparing the thoracic to the lumbar spinal cord expression profiles from the same G93A SOD1 mutant spinal cord tissue at a pre-symptomatic stage, at onset and at end-stage disease (R2: 0.944, 0.947 and 0.932 respectively) and comparing sham-operated and naive thoracic cord samples from wild type littermates at 30 minutes (R2: 0.973) and at 4 hours (R2: 0.962) from surgery. A technical replica experiment is also reported, based on the comparison of the gene expression profiles obtained from the same spinal cord sample (extracted at 30 minutes from compression injury) used to hybridize two separate Bead arrays (R2: 0.9872*). The significant R2 levels indicate that the Bead array technique reproduces the expected similarity of the samples chosen for the correlation analyses.
*: technical replica using RNA extracted from thoracic cord 30 minutes after injury (hybridization of two arrays in the same Bead Chip). The R2 is reported in bold.