Model of gene expression within a cell. Each genomic expression pattern at a given condition, denoted by xi, 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 aij, where aij = activity level of process j in condition i. The example shown uses data generated by Gasch et al. .
Lee and Batzoglou Genome Biology 2003 4:R76 doi:10.1186/gb-2003-4-11-r76