Variable levels of drift in tunicate cardiopharyngeal gene regulatory elements

Abstract

Our findings reveal heterogeneous levels of divergence across cardiopharyngeal <i>cis</i>-regulatory elements. These distinct levels of divergence presumably reflect constraints that are not clearly associated with gene function or position within the regulatory network. Thus, levels of <i>cis</i>-regulatory divergence or drift appear to be governed by distinct structural constraints that will be difficult to predict based on network architecture.