Oxygen metabolism in descendants of the archaeal-eukaryotic ancestor
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Article Date: 2026-02-18
Article URL: https://www.nature.com/articles/s41586-026-10128-z
Article Image / data: Figshare dataset
Summary
This study surveys genomes and metagenome-assembled genomes of lineages descended from the archaeal–eukaryotic ancestor (notably Asgard-related groups) to map their oxygen-handling machinery. Using comparative genomics, phylogenomics and protein structural analyses, the authors show that descendants display a mosaic of metabolic strategies: some retain or have acquired components of canonical electron transport chains (including complex I-like systems and haem–copper oxidases), others rely on hydrogenases and anaerobic pathways, and many appear adapted to microoxic or fluctuating oxygen conditions. The work integrates evidence from hydrogenase classification, respiratory complex evolution and environmental context to argue that flexible oxygen use was widespread among these lineages and that oxygen metabolism should be considered when reconstructing the physiology of the host that gave rise to eukaryotes.
Key Points
- Descendant archaeal lineages show diverse oxygen-related genes — from full aerobic components (haem–copper oxidases, complex I homologues) to strictly anaerobic systems.
- Many genomes encode hydrogenases and alternative electron transport chains, signalling metabolic flexibility between anaerobic and microoxic lifestyles.
- Structural and phylogenomic analyses indicate some respiratory complexes are ancient and modified rather than recent bacterial imports.
- Evidence supports existence of microoxic niches for Asgard-related archaea, consistent with environmental studies and the idea of fluctuating oxygen during early eukaryogenesis.
- Results have implications for the energetics of the archaeal host of mitochondria — oxygen-handling capacity may have been present or readily accessible, affecting timing and nature of mitochondrial symbiosis.
Why should I read this?
Short version: if you care about how eukaryotes got their energy systems (and why we breathe), this paper is gold. It cuts through a pile of genomes and shows descendants of the archaeal–eukaryotic ancestor aren’t uniformly anaerobic relics — they’re metabolically nimble, dodging between hydrogen-based and oxygen-based energy tricks. Saves you slogging through datasets yourself.
Author style
Punchy — the write-up emphasises why the metabolic diversity matters for big questions (eukaryogenesis, mitochondrial origin, Earth oxygen history). If you work in evolution, microbiology or bioenergetics the authors make a strong case to read the full analyses.
Context and Relevance
This work ties into ongoing debates about the host metabolism during eukaryote origin and the role of environmental oxygenation. By showing that oxygen-utilising components (and versatile alternatives) are present across descendant lineages, the study lends weight to models where the archaeal partner had at least intermittent access to oxygen or oxygen-derived chemistry. That intersects with Earth-history research on rising oxygen levels and with protein-evolution studies of respiratory complexes — so the findings are relevant across evolutionary biology, geobiology and microbial ecology.