Evolution of Cis-Regulatory Modules

摘要

Darwin has proposed that natural selection operates on small inheritable variations between indi-viduals and thus changes in evolution should be gradual. Recently more and more attention has been drawn to the regulatory sequences for their potential contribution to phenotypic variation and adap-tation. Features of cis-regulatory variations make them suitable to produce a continuum of gradual changes in the phenotype. In this essay we reviewed current knowledge of Cis-Regulatory Module (CRM)'s function and evolution. While functional divergence of CRM and co-evolution with the trans-factors surely occur, we focused on a set of well studied developmental genes whose expres-sion patterns tend to be well conserved across relatively long evolutionary time. However sequences underling these CRM show dramatic divergence, both in spacing sequences as well as known Tran-scription Factor Binding Sites (TFBS). We discussed specific properties of CRM related to its evo-lutionary dynamics. Then we focused on the population genetics details, attempting to investigate the type of evolutionary forces and the strength involved in the process. Finally we attempted to rec-oncile both conservation and evolution of CRM function and discussed remaining challenges in this field, pointing out directions for future studies.