Indeed, there is circumstantial evidence for gene expression divergence being a major contributor to duplicate gene retention (Force et al. 1999; Gu et al. 2002, 2004; Huminiecki and Wolfe 2004; He and Zhang 2005b).
However, it remains unclear about the genetic basis for the expression divergence of genes involved in major processes of glucose metabolism, such as genes responsible for oxidative phosphorylation, the TCA cycle, or fermentation.
Differential evolutionary rates between GST_N and GST_C and high degree of expression divergence have been regarded as the major drivers for the retention of duplicated genes and the adaptability to various stresses.
All these data suggested that expression divergence should be regarded as one of the major drivers to facilitate the retention of the tandemly duplicated genes in this subfamily.
Gene expression divergence and chromosomal rearrangements have been put forward as major contributors to phenotypic differences between closely related species.
From an evolutionary and population genetics perspective, the Malpighian tubules of D. melanogaster are of interest because they are the major tissue of expression of several genes that show evidence for adaptive expression divergence between populations from the ancestral species range (sub-Saharan Africa) and those from derived, non-African habitats.
Interestingly, our results showed that around 50% of expanded genes showed expression divergence within BT×623 or Keller, suggesting that their expression divergence is a major mechanism to drive the retention of expanded genes by segmental/tandem duplication or transposition by mobile elements.
Dong X, Akalin A, Sharma Y, Lenhard B. Translog, a web browser for studying the expression divergence of homologous genes.
Makova and Li found a negative correlation between expression divergence and protein sequence divergence in human paralogs[21].
In addition to expression conservation, expression divergence between species is also a measure for studying evolution of gene expression.
