The cover of this week’s edition of Nature, with the eye-catching title “Matters of the heart”, features a basic research study carried out exclusively by the Research Group on Evolution and Development (Evo-Devo) of the Genetics Section of the Faculty of Biology of the UB. The study deciphers one of the remaining enigmas about the transition between free and sedentary lifestyle in the ancestors of our own phylum: chordates.
Publishing an article in Nature –considered one of the foremost and most influential scientific journals in the world– is a coveted achievement for any researcher and for any university or research institution. When the article in question is signed exclusively by members of a single research group, the achievement is truly exceptional, so to have, as in this case, a basic research study featured as a cover article is virtually unheard of. It is probably the first such achievement recorded by the University of Barcelona and one of only a handful of examples in the history of research in Spain.
The paper proposes a new evolutionary scenario that helps to better understand the evolution of our phylum and to discover what the ancestor of tunicates ─the sister group of vertebrates─ were like. Specifically, it reveals that the massive gene losses which deconstructed the gene network in the heart of tunicates eased the transition to a free pelagic lifestyle in appendicularian tunicates from their ancestral sessile lifestyle.
Deciphering the impact of gene loss on biological evolution
For many years, the field of evolutionary biology had not paid much attention to gene losses, and most studies focused on how gene duplications could lead to new biological functions.
“In the era of genomics, however, we see that losing genes is not something exceptional in evolution, but rather a common phenomenon. First, it was thought that a gene was lost when it was no longer used (known as regressive evolution)”, points Cristian Cañestro, lecturer at the Section of Genetics of the UB, member of the Biodiversity Research Institute (IRBio) and principal researcher in the @EvoDevoGenomeUB research group.
“As shown in our study, we are identifying more and more gene losses that can be adaptive in nature”, he continues. “That is, losing certain genes can bring evolutionary advantages that can be related to the acquisition of biological innovations by organisms”.
The phylum of chordates is formed by the groups of vertebrates, tunicates (sister group of vertebrates) and cephalochordates. The basal position of cephalochordates and the fact that they are free-living organisms indicate that the ancestor of all chordates had a free-living style too. In the case of tunicates, however, there are sessile (ascidians) and free living (appendicularians) animals. Whether the common ancestor of tunicates was a peaceful filter feeder fixed to the seafloor or an active swimmer was a key debate to understanding what the predecessor from which vertebrates also originated was like.
“We need to understand the evolutionary history in order to understand ourselves”, says Jordi Garcia Fernàndez, full university professor of Genetics at the UB, principal researcher of the Evo-Devo Research Group and member Institute of Biomedicine of the UB (IBUB).
“This basic research is the basis for promoting the applicability of knowledge. For example, new animal models to study heart diseases, future therapeutic targets in biomedicine, patents, etc. This is why it is worth highlighting the effort being made by public universities in this direction”, adds Jordi Garcia-Fernàndez, Vice-Rector for Research at the UB.
“In a highly competitive international context, it is not at all common for a team from a single public university to exclusively sign a scientific article in a such prestigious journal. In the case of the UB and Nature, for example, less than five previous publications, including this one, have appeared in the format of this article. Therefore, the results of the new study featured in the cover highlight the value of the research carried out at public universities and highlight the urgent need to give them more support and to increase their funding in order to advance in the world of research and knowledge,” concludes Jordi Garcia-Fernàndez.
Reference article:
Ferrández-Roldán, A.; Fabregà-Torrus, M.; Sánchez-Serna, G.; Duran-Bello, E.; Joaquín-Lluís, M.; Bujosa, P.; Plana-Carmona, M.; Garcia-Fernàndez, J.; Albalat, R.; Cañestro, C. «Cardiopharyngeal deconstruction and ancestral tunicate sessility». Nature, November 2021. Doi: 10.1038/s41586-021-04041
