Oh my, what big (and new) eyes you have!
Speaker: Isabel Almudi, Ph.D. Developmental Biology, Evolutionary Biology Andalusian Center for Developmental Biology, Sevilla, Spain
Organizer: IRB Barcelona
Date: Wednesday, 20 September 2017, 15.00h
Place: Aula Fèlix Serratosa, Parc Científic de Barcelona, Spain
Host: Jordi Casanova, IRB Barcelona
Evolutionary innovations are biological revolutions: new organs are critically associated with the emergence of new species and their exploitation of new niches. Despite their importance in the history of life, how morphological novelty arises and evolves is a long-standing question in Evolutionary Biology. How the genetic network associated to the new structure appears? How this new structure is functionally and anatomically integrated into the pre-existing body plan? One of the most striking examples of a sexually dimorphic novel structure occurs in males of the mayfly species Cloeon dipterum. Cloeon males develop, in addition to the compound eyes (shared by males and females), an extra pair of extremely large dorsal, turban-shaped eyes. Thus, by comparing males versus females, this mayfly species provides a privileged system to understand the origin and integration of new structures.
To answer these questions, first, we have successfully established a C. dipterum culture in the lab. Next, we describe the development of the eye and its integration with the optic lobes of male and female Cloeon nymphs using confocal and electronic microscopy. Furthermore, we compare sex-specific gene expression in nymphal heads, with a special focus on genes of the highly conserved Retinal Determination Network (RDN), to show how RDN elements could have evolved to play a role in the origin of this novel sexually dimorphic visual organ. Finally, the use of Cloeon to study evolutionary novelties goes well beyond the sexually dimorphic turbanate eyes. Insect wings are perhaps the most iconic morphological innovation in animals and their origin led to the conquest of the sky and the adaptation to a huge diversity of new ecological niches. This key structure first appeared among the ancestral mayflies, thus, the establishment of the first mayfly model system in the lab is an unprecedented opportunity to test the different proposed hypotheses about the origin of wings in their extant relatives.
Cell and Developmental Biology Programme Seminar