Land animal evolution: genomic landmarks on the path to terrestrial life

ongoing

All animals share a common origin: a marine one. To conquer land from marine environments, animals changed radically the way they breath, reproduce, move or smell. And they did it multiple times in the history of Earth, with terrestrial animals massively outnumbering aquatic ones. Understanding terrestrialization is therefore key to comprehending animal biodiversity and biological adaptation. Despite the relevance of such an episode, the genetic underpinnings orchestrating terrestrialization in animals are largely unexplored. The project will test the hypothesis that animals are equipped with a highly plastic ‘terrestrialization genetic toolkit’ that allowed their adaptation to the extreme environmental conditions in terrestrial ecosystems. We will focus on two pivotal questions: which genes facilitated life on land and how do they differ between aquatic and terrestrial animals?, and how did animals reshape their genomes to adapt to dry land? Moreover, we will study two case examples of critical processes common to all terrestrial animals -breathing and protection against UV light- to illuminate what molecular and biochemical changes allowed terrestrial animals to breathe and repair their DNA after UV light damage. To achieve this, we will (i) identify the gene repertoire orchestrating the extreme physiological and metabolic changes in aquatic and terrestrial lineages, (ii) characterize the dynamics of these genes to understand the role of gene loss, duplications and horizontal gene transfer, and (3) discover the adaptive mutations that led respiratory pigments and DNA repair proteins to gain their functions via molecular engineering techniques to resurrect their ancestral ‘paleophenotypes’. This project will deliver fundamental insights into a core question in evolutionary biology: what shaped the land animal genetic toolkit. Furthermore, it will provide insights into the evolution of key proteins relevant to human health and industry.