Tissue-Driven Hypothesis of Transcriptome Evolution: An Update

In past decade, many reports have demonstrated that tissues in multi-cellular organisms may play important roles to shape the pattern of genome evolution. The tissue-driven hypothesis was then coined, claiming that tissue-specific factor as the common resource of functional constrain may underlie the positive correlations between tissue expression divergence, sequence divergence, or the expression tolerance of duplication divergence. However, the original version of tissue-driven hypothesis cannot rule out the tissue-specific effect of mutational variance. In this perspective, we solve this problem by modifying the evolutionary model that underlies the tissue expression evolution. Reanalysis of the microarray data reanalysis has revealed the relative importance between tissue-specific functional constraints and mutational variances in the tissue evolution. Finally, we outline how to utilize RNA-seq technology to further investigate the tissue expression evolution in the case of multiple tissues and species.