Based on these premises we reasoned that if the state of the transcriptome and its changes are important determinants of cell functions, differences in transcript abundance whatever their origin, genetic or non genetic, may contribute to disease pathogenesis. Moreover, the transcriptome might integrate information from numerous sources and inform on the current pathophysiological state of the organism. To assess these possibilities, a global characterization of the variability of the transcriptome, integrating genetic and non genetic influences was undertaken. The study focused on peripheral blood monocytes because these cells may be isolated from an easily accessible tissue and play a key role in the pathogenesis of immune disorders and atherosclerosis-related diseases [18]. In addition, working on a single cell type reduces the complexity of transcriptome data and may avoid possible biases resulting from the heterogeneous cell-types distribution in different samples as it is the case when using whole blood or leucocytes RNAs.
