Subterranean Fishes of the World

5986

2022

Biologie Aujourd’hui

49-53

216

Abstract - The toolbox of developmental evolution or how Mexican cave fishes lost their eyes. The fish Astyanax mexicanus comes in two very different forms: a “normal” river morph, and a blind, depigmented cave morph, living in the total and permanent darkness of Mexican caves. This species is on the way to becoming a model of choice in evolutionary and comparative biology, both for the study of the evolution of behavior, physiology or morphology, and for molecular genetics or population genetics. Here, I present the advancement of knowledge in the field of the developmental evolution of the eye of the cave morph. By rewinding back in time its development from the eye of the larva to the retinal field at the end of gastrulation, the cave-dwelling Astyanax embryo reveals mechanisms and processes likely to contribute to evolutionary variations between species, but also to pathological variations in the morphogenesis of the optic region. Keywords: degeneration, morphogenesis, neural plate, transcription factors, embryonic signaling Introduction Évolution développementale, ou évo-dévo : de quoi s’agit-il ? C’est une discipline à la croisée de la biologie de l’évolution et de celle du développement, qui recherche dans les processus développementaux l’origine de l’extraordinaire diversité morphologique des êtres vivants, ainsi que des grandes transitions ou innovations évolutives. Faire apparaître un nouveau trait ou perdre une structure, en

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