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Rooted phylogeny of the three superkingdoms.

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Author

Summary, in English

The traditional bacterial rooting of the three superkingdoms in sequence-based gene trees is inconsistent with new phylogenetic reconstructions based on genome content of compact protein domains. We find that protein domains at the level of the SCOP superfamily (SF) from sequenced genomes implement with maximum parsimony fully resolved rooted trees. Such genome content trees identify archaea and bacteria (akaryotes) as sister clades that diverge from an akaryote common ancestor, LACA. Several eukaryote sister clades diverge from a eukaryote common ancestor, LECA. LACA and LECA descend in parallel from the most recent universal common ancestor (MRUCA), which is not a bacterium. Rather, MRUCA presents 75% of the unique SFs encoded by extant genomes of the three superkingdoms, each encoding a proteome that partially overlaps all others. This alone implies that the common ancestor to the superkingdoms was very complex. Such ancestral complexity is confirmed by phylogenetic reconstructions. In addition, the divergence of proteomes from the complex ancestor in each superkingdom is both reductive in numbers of unique SFs as well as cumulative in the abundance of surviving SFs. These data suggest that the common ancestor was not the first cell lineage and that modern global phylogeny is the crown of a "recently" re-rooted tree. We suggest that a bottlenecked survivor of an environmental collapse, which preceded the flourishing of the modern crown, seeded the current phylogenetic tree.

Publishing year

2013

Language

English

Pages

1593-1604

Publication/Series

Biochimie

Volume

95

Issue

8

Document type

Journal article

Publisher

Elsevier

Topic

  • Biological Sciences

Keywords

  • Rooted phylogeny
  • Genome content/protein domain
  • Reductive evolution
  • Gene duplication
  • Innocuous HGT

Status

Published

Research group

  • Microbial Ecology

ISBN/ISSN/Other

  • ISSN: 1638-6183