EVOLUTION AND DEVELOPMENT OF BILATERIA SENSORY SYSTEMS: A QUANTITATIVE APPROACH

Abstract

Animal organisms, including humans, are simply fascinating. Their complexity and diversity havealways been a source of questioning and wonder. One of their principal characteristics is the development of a biological electric circuit receiving inputs from the environment which in return generates a plethora of responses promoting survival, reproduction and ultimately evolution. The first component of this circuit is the interface collecting the many stimuli surrounding the organism which, we know as the sensory system. This system is compartmentalized at the cellular level with each sensory cell being dedicated to sensing a specific cue: temperature, chemicals, photons, vibrations, etc. The main goal of this thesis is to shed light on the genetic and molecular mechanisms underlying the development and evolution of the animal sensory system, especially for the ones with bilateral symmetry called Bilaterians. To do so, I focused my experimental strategy on transcriptional singleomics applied to two different model organisms to have both macro- and micro-evolutionary perspectives. In the first study case, I explored the ontogeny of the so-called fourth embryonic layer of vertebrates, the neural crest and cranial placodes, and resolved a 35-year-old debate on their origin. In the second, I fully described for the first time the olfactory genetic code of the disease transmitting mosquito Aedes aegypti.