Experimental approaches to evaluate the contributions of candidate cis-regulatory mutations to phenotypic evolution

Elucidating the molecular bases by which phenotypic traits have evolved provides a glimpse into the past, allowing the characterization of genetic changes that cumulatively contribute to evolutionary innovations. Historically, much of the experimental attention has been focused on changes in protein-coding regions that can readily be identified by the genetic code for translating gene coding sequences into proteins. Resultantly, the role of noncoding sequences in trait evolution has remained more mysterious. In recent years, several studies have reached an unprecedented level of detail in describing how noncoding mutations in gene cis-regulatory elements contribute to morphological evolution. Based on these and other studies, we describe an experimental framework and some of the genetic and molecular methods to connect a particular cis-regulatory mutation to the evolution of any phenotypic trait.