Morphological novelties are associated with innovative functions that have been conductive to major revolutions in the history of life: the development of limbs from fins to colonize the land, the invention of wings in insects that allowed the occupation of the air or the emergence of the placenta in mammals are amongst them. Nevertheless, it is still an open debate what genetic changes underlie these novelties, and whether these are generated through accumulation of progressive small changes or rather by major leaps. Despite their importance in the history of life, how morphological novelty arises and evolves is a long-standing question in Evolutionary Biology. One of the most striking examples of a sexually dimorphic novel structure is the extra pair of eyes present in the males of the mayfly species Cloeon dipterum. The males of this species develop, in addition to the compound eyes (shared by males and females), an extra pair of extremely large dorsal, turban-shaped eyes. EvoNovo wanted to take advantage of this novel visual system to make ground-breaking advances in the way we understand the genetic forces that control the origin of new organs and structures during evolution.
To investigate the appearance of the turbanate eye in C. dipterum, we combined a number of experimental approaches, including non-invasive imaging, gene expression analyses, genomics, transcriptomics, and epigenomics to knit the gene regulatory network responsible for the development of the turbanate eye. EvoNovo described the formation of this new organ in males and the regulatory networks that have evolved to originate this structure in the males of this species.
In addition, the establishment of C. dipterum as a model serves to other researchers as a foundation for further investigations in an organism placed in a key position in the phylogeny of insects.
