MicroRNAs tell an evo-devo story.

Evolutionary developmental biology, often called evo-devo, seeks to understand the ancestral relationship among organisms by comparing their developmental strategies and ultimately reconstructing the pathways that led to the extraordinary variety of biological forms. The insights from this synthesis of developmental biology and evolutionary principles are useful for understanding the development of the nervous system. The pervasive and crucial roles of microRNAs in nervous system development suggest that these short non-coding transcripts deserve a chapter in the unfolding evo-devo story. The structure of microRNAs, their physical proximity to other genes and their network effects on targets make this class of transcripts tractable genetic material for evolutionary change.