Expression divergence and copy number variation in the human genome

DNA copy number variation (CNV) was recently discovered as a significant part of human genetic variation. This variation affects genes as well as intergenic regions. Herein, current insight into the effects of CNV on gene expression is summarized. The consequences of intergenic CNVs are poorly understood. For CNV affecting genes, a dosage compensation mechanism seems to be applied on a subset of genes only, while others show augmented expression caused by increasing copy number. For the latter case, extensive literature reports a positive correlation between gene copy number and gene expression. Recent advances in techniques for genome-wide measurements of CNV and gene expression are described. These advances will soon allow the generation of comprehensive maps of these two phenomena, which will contribute to our understanding of the mechanisms underlying how CNV affects gene expression.