Abstract

Selected results from our research on embryonic development in various fly species (Diptera) will be used to address the question of how developmental processes undergo major evolutionary change. The first part of the presentation examines the evolution of extraembryonic tissue and focuses on how the developmental trajectories of serosa and amnion tissues merged in higher flies into one, called amnioserosa. The second part examines findings pertaining to the question of how unique new axis-specifying genes acquired their function. I will end this section by discussing conceptual parallels between the evolution of extraembryonic tissues and anterior determinants. The third part briefly explores the question of how and why dipterans evolved new mechanisms of axis specification that are strikingly different from a widely conserved core mechanism found in other metazoans. The fourth part will raise open question that we have started to tackle. It is my hope that the seminar also will convey the unique added value of a multi-species approach in understanding developmental mechanisms while looking at their evolution.