cis-trans compensation

Llopart A 2012 The rapid evolution of X-linked male-biased gene expression and the large-X effect in Drosophila yakuba, D. santomea and their hybrids. Mol Biol Evol, in press.
doi:10.1093/molbev/mss190

• the detection of a large fraction of changes in both trans- and cis-regulatory elements (i.e., CREs) in D. yakuba and D. santomea opens the possibility of rapid coevolution between CRE and trans-acting factors
• cis-trans coevolution has been proposed in the framework of compensatory changes occurring independently in different species' genetic backgrounds to maintain an optimal expression level
• the preferential interaction between trans-factors and CRE of the same species has only been suggested recently for a small number of genes

• most autosomal genes evaluated using pyrosequencing show significant differences in the abundance of transcripts produced by each of the two allelic gene copies
• using species of the D. simulans clade, Takahasi et al. (2011) reported similar findings in three out of the seven genes assayed in the reciprocal introgressions of heterospecific alleles in otherwise "pure species" genetic backgrounds

• theoretical models on transcriptional regulation indicate that interactions between CREs and trans-acting factors can provide the type of pleiotropic and epistatic effects that underlie hybrid dysfunction