text: Synexpression is a type of non-random eukaryotic gene organization.  Genes in a synexpression group may not be physically linked, but they are involved in the same process and they are coordinately expressed.  It is expected that genes that function in the same process be regulated coordinately.  Synexpression groups in particular represent genes that are simultaneously up- or down-regulated, often because their gene products are required in stoichiometric amounts or are protein-complex subunits. It is likely that these gene groups share common cis- and trans-acting control elements to achieve coordinate expression.
  Synexpression groups are determined mainly by analysis of expression profiles compiled by the use of DNA microarrays. The use of this technology helps researchers monitor changes in expression patterns for large numbers of genes in a given experiment.  Analysis of DNA microarray expression profiles has led to the discovery of a number of genes that are tightly co-regulated.