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Oxygen-Tolerant Asgard Archaea Bolster Mitochondrial-Origin Theory in Nature Study

The study identifies oxygen-capable Asgard archaea in oxygenated coastal settings, narrowing the gap in how an archaeal host met an aerobic symbiont.

Overview

  • An international team led by the University of Texas at Austin assembled more than 13,000 microbial genomes from roughly 15 terabytes of environmental DNA collected across multiple marine expeditions.
  • Hundreds of newly recovered Asgard genomes nearly doubled the group’s known diversity and expanded their enzymatic repertoire, including a doubling of known enzymatic classes.
  • Genomic analyses highlight Heimdallarchaeia, the lineage closest to eukaryotes, with genes consistent with oxygen use or tolerance.
  • AlphaFold2 predictions show several Heimdallarchaeia proteins closely resemble eukaryotic components for oxygen-based, energy-efficient metabolism.
  • Samples from shallow coastal sediments and the water column place oxygen-tolerant Asgards alongside aerobic alphaproteobacteria, supporting an oxygen-enabled endosymbiosis scenario reported in Nature.