Periodic Reporting for period 3 - SEA2LAND (Land animal evolution: genomic landmarks on the path to terrestrial life)
Período documentado: 2024-02-01 hasta 2025-07-31
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 the evolutionary origin of 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? This project will deliver fundamental insights into a core question in evolutionary biology: what shaped the land animal genetic toolkit.
To pinpoint the genes potentially facilitating terrestrialization, we collected more than 1,000 specimens from multiple marine and terrestrial species from virtually all animal phyla with terrestrial forms. Through a series of 're-terrestrialization' experiments and genomics and transcriptomics analyses, we are characterizing the 'terrestrialization genetic toolkit' in each species. Our results so far indicate that several lineages seem to have different such toolkits, but some common elements seem to be arise as central in the genetic machinery underlying such adaptation to habitat change. Further analyses will shed light on which genetic elements seem to be common (or not) in terrestrial lineages.
This is the first time that such a vast collection of datasets from scientifically neglected animal species such as earthworms, ribbon worms, mollusks or velvet worms have been amassed and explored in a comparative manner. Through the combination of different 'omics' methodologies, we expect to pinpoint the genetic elements underlying adaptation to terrestrial environments, and how different evolutionary mechanisms acting in the gene repertoire (eg, gene gain, loss and duplication) have reshaped the genomic landscape of the ancestors of land animals. We are one step closer to understanding how animal terrestrial biodiversity originated.