Recording intelligenceAI-generated brief · check the source for context

Origins of Eukaryotes and Giant Viruses

1:32:28 recording · AUTO · 2 speakers

Listen to the original

Listen to the episode

Brief overview

A new preprint argues viruses and many bacteria, not just the mitochondrial ancestor, built the first eukaryote.

  1. Mitochondria were not the only genetic donorAt least three other bacterial groups sit in the same weight class as alpha proteobacteria in the acquisition share.
  2. Viruses match archaea as contributors, at 10%Over half of that viral 10% comes from the large-genome DNA viruses, the giant viruses discovered too recently to be in Woese's picture.
  3. Data replaced argument, but interpretation is the hard partNels calls this a field once built on imagination and argument that now has huge datasets and struggles to pull signal from two billion years of noise.
Executive Summary AI
  • Vincent Racaniello opens Twevo episode 107 from Microbe TV with Nels Elde in Salt Lake City, warming up with ski talk, dam removals letting Chinook salmon spawn in Oregon, and whether Miller-Urey or Nick Lane's alkaline vents better explain the origins of life.0:00
  • The paper under discussion is a bioarchive preprint, Diverse Ancestries Reveal Complex Symbiotic Interactions During Eukaryogenesis, from Tony Gabaladon's lab with first author Moises Bernabeu at the Barcelona Institute of Science and Technology and the Barcelona Supercomputing Center, and it reached Nels through a Eugene Coonan Facebook post.14:29
  • The authors infer the proteome of LECA, the last eukaryotic common ancestor that lived roughly two billion years ago, from about 65,000 bacterial pan genomes, 1.3 million clusters of virus sequences, archaeal and eukaryotic proteomes, building three roughly 50% overlapping 100-proteome datasets and mapping the result onto KEGG metabolic pathways rather than trees.33:59
  • In panel A, 40% of the inferred proteins are eukaryote-only innovations, including almost 1,200 eukaryotic signature proteins, while the other 60% are acquisitions split 40% bacteria, 10% archaea and 10% viruses, with alpha proteobacteria only one of at least four bacterial groups making big contributions.1:00:48
  • More than half of the viral share traces to giant DNA viruses, which Nels frames as genetic diplomats shuttling kinases and post-translational modification genes through microbial mats, while cautioning that the signal may simply follow from adding so many virus sequences for the first time.1:06:07
Key Quote
“But he said the Miller-Urey is just nonsense.”
— Vincent Racaniello12:47
Key Quote
“You know, we have no time machine here.”
— Nels Elde27:12
Key Quote
“The viruses are acting as kind of genetic diplomats,”
— Nels Elde53:52