University of Valencia researcher Fernando Ballesteros has been awarded the Cozzarelli Prize for his studies on the emergence of complex life. Ballesteros is the second Spaniard to receive this distinction. He is a co-author of the article published in the prestigious journal Proceedings of the National Academy of Sciences (PNAS), which explains how simple cells gave rise to complex ones. The research sheds light on understanding what we are and why.

Each year, the U.S. National Academy of Sciences awards the Cozzarelli Prizes to scientists whose contributions stand out for their scientific excellence and originality. These contributions are selected from those published in the Proceedings of the National Academy of Sciences and the journal PNAS, one of the three most influential and prestigious multidisciplinary scientific journals in the world, along with Science and Nature.

This year's prize, awarded to the University of Valencia, recognizes a highly multidisciplinary research project, co-led by Fernando Ballesteros, an astronomer and astrobiologist at the University of Valencia's Astronomical Observatory, that combines physics, mathematics, statistics, computer science, and biology. The research, "The emergence of eukaryotes as an evolutionary algorithmic phase transition," demonstrates how the appearance of complex cells with a nucleus, like our own, was an inevitable event. This research discovered that as primitive prokaryotic cells became more complex, they required increasingly longer proteins, which were increasingly difficult to obtain. This led to a mathematically predictable "computational crisis" that forced life, 2.6 billion years ago, to change the way the genetic code functions. It was a unique, abrupt, and crucial transition in life, giving rise to eukaryotic cells.

For the first billion years of life's history, there were simple, nucleus-less cells, like modern bacteria (prokaryotes). Suddenly, and we don't know how, complex, nucleus-bound cells (eukaryotes), like those that make up our bodies, plants, and fungi, evolved from them. How they appeared is a mystery and one of the main areas of research in biology, known as the 'black hole of biology'. Ballesteros's research sheds light on this enigma. According to the researcher, after this exhaustive study, the emergence of complex life was inevitable.

The U.S. National Academy of Sciences awards six prizes annually, one for each of the scientific disciplines represented by the academy. This year, the winning research was selected from 3,600 papers published in PNAS in 2025. Only once before have these prestigious awards been given to researchers from a Spanish university (the University of the Basque Country, in 2021).

PNAS