Chapter category: Evolution
Reconstructing the Universal Tree of Life
The Genetic Code and the Origin of Life
Edited by: Lluis Ribas de PouplanaISBN: 0-306-47843-9
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Chapter authors:
James R. Brown
The universal tree of life depicts the evolutionary relationships of all living things by grouping them into one of three Domains of life; the Archaea (archaebacteria), Bacteria (eubacteria) and Eucarya (eukaryotes). The “canonical universal tree” topology is actually a composite of phylogenies based on single ribosomal RNA gene trees and duplicated, paralogous protein gene trees. The salient features of the canonical universal tree are: 1) all three Domains are mono/holophyletic; 2) Archaea and eukaryotes are sister groups with the Bacteria at the root, and; 3) thermophilic bacteria are the earliest evolved bacterial lineage. Recent studies based on new genome sequence data suggest that the universal tree has been “uprooted” by extensive horizontal gene transfer (HGT). However, the scope of HGT is still unclear and reports of extensive trans-Domain HGT based on sequence homology, without supporting phylogenetic analysis, need careful reconsideration. Phylogenetic analysis of combined conserved proteins suggests that there is still underlying support for the concept of the universal tree.
Additional chapters from this book:
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Extant Variations in the Genetic Code
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Expanding the Genetic Code in Vitroand in Vivo
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Reconstructing the Universal Tree of Life
James R. Brown
The universal tree of life depicts the evolutionary relationships of all living things by grouping them into one of three Domains of life; the Archaea (archaebacteria), Bacteria (eubacteria) and ...
The Scope of Selection
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We have estimated the maximal size for an RNA motif recoverable from selection-amplification for new RNA activities, under conditions that span those in present laboratory use. The number of s...
