Coexpression, coregulation, and cofunctionality of neighboring genes in eukaryotic genomes

Accumulating evidence indicates that gene order in eukaryotic genomes is not completely random and that genes with similar expression levels tend to be clustered within the same genomic neighborhoods. The mechanism behind these gene coexpression clusters is as yet unclear. In this article, plausible biochemical, genetic, evolutionary, and technological determinants of this pattern are briefly reviewed.