Figure 1

Model of gene expression within a cell. Each genomic expression pattern at a given condition, denoted by x _i , is modeled as linear combination of genomic expression programs of independent biological processes. The level of activity of each biological process is different in each environmental condition. The mixing matrix A contains the linear coefficients a _ij , where a _ij = activity level of process j in condition i. The example shown uses data generated by Gasch et al. [48].