Article

Global trends of whole-genome duplications revealed by the ciliate Paramecium tetraurelia

First publ. in: Nature 444 (2006), pp. 171-178 DOI:urn:nbn:de:bsz:352-opus-42849
Source: OAI

ABSTRACT The duplication of entire genomes has long been recognized as having great potential for evolutionary novelties, but the mechanisms underlying their resolution through gene loss are poorly understood. Here we show that in the unicellular eukaryote Paramecium tetraurelia, a ciliate, most of the nearly 40,000 genes arose through at least three successive whole-genome duplications. Phylogenetic analysis indicates that the most recent duplication coincides with an explosion of speciation events that gave rise to the P. aurelia complex of 15 sibling species. We observed that gene loss occurs over a long timescale, not as an initial massive event. Genes from the same metabolic pathway or protein complex have common patterns of gene loss, and highly expressed genes are over-retained after all duplications. The conclusion of this analysis is that many genes are maintained after whole-genome duplication not because of functional innovation but because of gene dosage constraints.

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Keywords

ciliate
 
entire genomes
 
evolutionary novelties
 
gave rise
 
gene dosage constraints
 
gene loss
 
genes
 
initial massive event
 
P. aurelia complex
 
Phylogenetic analysis
 
protein complex
 
recent duplication coincides
 
speciation events
 
three successive whole-genome duplications
 
unicellular eukaryote Paramecium tetraurelia