VxInsight validation: noise dependence
To test the stability of the gene map to noise in the expressions, we investigated the results of adding four levels of white noise. We added noise drawn from a gaussian distribution with mean zero and increasing standard deviations 0.001, 0.010, 0.050, and 0.100) to the Pearson correlations, and recomputed the gene expression maps. For each level of noise, we generated 20 random data sets. We calculated the 200 nearest neighbors for each gene in each ordination, and then determined the overlap between the new ordinations with the original ordination presented in the paper. The data show that some clusters are resistant to significant amounts of noise, and that many clusters remain relatively near to each other despite the noise.