In Memoriam: Professor Peer Bork (1963–2026)

With great sorrow, we remember the passing of Professor Peer Bork, an extraordinary scientist, visionary leader in microbiome research and bioinformatics, and a generous mentor to generations of researchers .

The scientific legacy of Peer Bork is best understood not as a sequence of projects, but as a continuous expansion of scale guided by a single principle: evolution organizes biological complexity. Over more than three decades at the European Molecular Biology Laboratory, he helped transform computational biology into a discipline capable of extracting general laws from large-scale data.

In the 1990s, as genome sequencing accelerated, Bork recognized that interpretation—not data generation—was the central challenge. Protein domains, he argued, form the grammar of biological function. Through comparative genomics and evolutionary conservation, functional relationships could be inferred systematically. Foundational work such as Bork and Koonin (Nature Genetics, 1996) articulated this predictive framework, while Enright et al. (Nature, 1999) demonstrated that gene fusion events reveal functional associations between proteins. These insights became cornerstones of genome annotation and protein interaction prediction.

In the early 2000s, Bork expanded his focus from molecular components to biological systems. Studies such as Snel, Bork and Huynen (Nature Genetics, 2002) and von Mering et al. (Nature, 2003) showed that cellular networks are modular structures shaped by evolutionary constraints. Systems biology, in his hands, was not an abstraction but instead evolutionary systems biology: networks reflected selection, history, and functional necessity.

The next scale was microbial ecosystems. Through landmark studies including Qin et al. (Nature, 2010) and Arumugam et al. (Nature, 2011), Bork helped transform microbiome research into quantitative ecology. Microbial communities were revealed as structured, stratifiable systems whose functional gene repertoires could be analyzed at population scale. The microbiome became not merely a list of taxa, but an ecosystem governed by ecological and evolutionary principles.

Peer Bork then extended this logic to the planet. Kim et al. (2025), “Planetary microbiome structure and generalist-driven gene flow across disparate habitats,” demonstrated that microbial gene flow links distant ecosystems through cosmopolitan generalists, suggesting that Earth’s microbiomes form a dynamically interconnected system. This planetary perspective aligns closely with the ambitions of the World Microbiome Partnership, which positions microbiome science within a One Health framework connecting environmental, animal, and human health. Bork strongly supported the vision of an international microbiome observatory to monitor, evaluate, and restore microbial biodiversity as a foundation of planetary resilience.

Across scales—from domains to genomes, from networks to ecosystems, and from ecosystems to the biosphere—his intellectual trajectory remained coherent. He consistently pushed biology beyond description toward prediction, insisting that large-scale data must be interpreted through evolutionary reasoning.

Beyond his publications, his influence lives on through the scientists he trained, and the integrative and comparative spirit he championed. Modern computational biology—quantitative, ecological, and evolutionary—bears his imprint. The systems he studied continue to evolve, and so will the scientific vision he helped define.