Researchers use RNA-Seq and microarray data to show that cells “leak” gene expression and postulate that it may be because shutting down the gene expression completely (fixing the leak) would be more costly to the cell than any deleterious effects or unwanted consequences caused by the leak.
Visual inspection of both microarray and RNA-seq data revealed two overlapping main components of the distribution of gene expression levels which they designate as the lowly expressed (LE) and highly expressed (HE) genes. They further present evidence that the LE genes are expressed rather than simply being experimental background and that the HE genes are functionally active. The majority of LE genes are expressed at less than one copy per cell on average, and the authors wonder whether such stochastic expression has any function.
Hebenstreit D, Fang M, Gu M, Charoensawan V, van Oudenaarden A, Teichmann SA. (2011) RNA sequencing reveals two major classes of gene expression levels in metazoan cells. Mol Syst Biol 7, 497. [article]