Effects of regulatory evolution on morphological diversity

Abstract

An important task in evolutionary biology is to understand the reason for and mechanisms of morphological diversification. Studies in evolutionary developmental biology have revealed that, rather than being invented repeatedly from scratch, many complex morphological structures have evolved by modification of ancient regulatory networks. In other words, morphological diversity is not always produced by changes in the protein-coding region of regulatory genes; rather, it largely depends on the evolution of gene regulation. As the main components of the regulatory regions of a gene, cis regulatory elements bind to specific trans factors and determine the precise expression of the gene in time, place and amount. As a result, gain, loss, change or modification of cis regulatory elements may lead to shifts in gene expression, which, in turn, generate morphological diversity. Here, by reviewing recent progress in this and related fields, we summarize the basic features of gene regulation in eukaryotes, elucidating its fundamental evolutionary pattern and revealing its importance in generating morphological diversity.