A neutral genetic mutation –a fluke in the evolutionary process with no apparent biological purpose– that appeared over 700 million years ago in biological evolution could help explain the origin of complex organs and structures in human beings and other vertebrates, according to an article published in Nature Communications by a team led by Professor Jordi García-Fernàndez, from the Faculty of Biology of the University of Barcelona (UB) and the Institute of Biomedicine of the UB (IBUB) at the Barcelona Science Park (PCB), Manuel Irimia (CRG) and Maria Ina Arnone (Anton Dohrn Zoological Station, Italy).

A gene can code for different proteins—with diverse functionality—through the genetic mechanism of alternative splicing. In some human cell types, this process is controlled by regulatory proteins such as ESRP1 and ESRP2, involved in morphogenic processes. Therefore the genome controls all embryonic developmental processes and interaction processes among cells. If this interaction model changes, it can also alter the morphology of biological structures. However, the molecular basis that modulates these interactions is still unknown.

The article in Nature Communications, whose first author is Demian Burguera (UB-IBUB and CRG), there is a new approach from the field of evolutionary developmental biology (evo-devo). This is a relatively new paradigm in the study of evolution, which analyses the mechanisms and evolutionary processes related to the development and morphogenesis of living beings.

The work shows how the same regulatory genes have been used to generate different organs and biological structures in living beings during the evolutionary process. In the same vein, the article describes how an accidental mistake—an apparently meaningless mutation that took place over 700 million years ago—became the molecular driver for complex morphological developments in a number of vertebrates (including the human species). 

Specifically, this mutation -which would have taken place after the separation of jellyfishes and sea anemones, and prior to the appearance of vertebrates in evolution-  affected a gene of the Fgfr (fibroblast growth factor receptors) family. Curiously, this genetic change triggered, millions of years later, the connection between two gene regulatory networks (those controlled by ESRP and by Fgfr), which became essential for the origin of many vertebrate organs and structures (lungs, forelimbs and inner ear). 
 

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Demian Burguera, Yamile Marquez, Claudia Racioppi, Jon Permanyer, Antonio Torres-Méndez, Rosaria Esposito, Beatriz Albuixech-Crespo, Lucía Fanlo, Ylenia D’Agostino, Andre Gohr, Enrique Navas-Perez, Ana Riesgo, Claudia Cuomo, Giovanna Benvenuto, Lionel A. Christiaen, Elisa Martí, Salvatore D’Aniello, Antonietta Spagnuolo, Filomena Ristoratore, Maria Ina Arnone, Jordi Garcia-Fernàndez, Manuel Irimia. Evolutionary recruitment of flexible Esrp-dependent splicing programs into diverse embryonic morphogenetic processes. Nature Communications, 2017; 8 (1) DOI: 10.1038/s41467-017-01961-y