MBE Advance Access originally published online on September 8, 2004
Molecular Biology and Evolution 2005 22(1):85-90; doi:10.1093/molbev/msh254
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Research Article |
Gene Transfers from Nanoarchaeota to an Ancestor of Diplomonads and Parabasalids

* The Canadian Institute for Advanced Research, Program in Evolutionary Biology, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada; and
Institute of Cell and Molecular Biology, Uppsala University, Biomedical Center, Uppsala, Sweden
E-mail: jan.andersson{at}icm.uu.se.
Rare evolutionary events, such as lateral gene transfers and gene fusions, may be useful to pinpoint, and correlate the timing of, key branches across the tree of life. For example, the shared possession of a transferred gene indicates a phylogenetic relationship among organismal lineages by virtue of their shared common ancestral recipient. Here, we present phylogenetic analyses of prolyl-tRNA and alanyl-tRNA synthetase genes that indicate lateral gene transfer events to an ancestor of the diplomonads and parabasalids from lineages more closely related to the newly discovered archaeal hyperthermophile Nanoarchaeum equitans (Nanoarchaeota) than to Crenarchaeota or Euryarchaeota. The support for this scenario is strong from all applied phylogenetic methods for the alanyl-tRNA sequences, whereas the phylogenetic analyses of the prolyl-tRNA sequences show some disagreements between methods, indicating that the donor lineage cannot be identified with a high degree of certainty. However, in both trees, the diplomonads and parabasalids branch together within the Archaea, strongly suggesting that these two groups of unicellular eukaryotes, often regarded as the two earliest independent offshoots of the eukaryotic lineage, share a common ancestor to the exclusion of the eukaryotic root. Unfortunately, the phylogenetic analyses of these two aminoacyl-tRNA synthetase genes are inconclusive regarding the position of the diplomonad/parabasalid group within the eukaryotes. Our results also show that the lineage leading to Nanoarchaeota branched off from Euryarchaeota and Crenarchaeota before the divergence of diplomonads and parabasalids, that this unexplored archaeal diversity, currently only represented by the hyperthermophilic organism Nanoarchaeum equitans, may include members living in close proximity to mesophilic eukaryotes, and that the presence of split genes in the Nanoarchaeum genome is a derived feature.
Key Words: Nanoarchaeum equitans Trichomonas vaginalis Giardia lamblia lateral gene transfer phylogeny
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
Y. Inagaki, Y. Nakajima, M. Sato, M. Sakaguchi, and T. Hashimoto Gene Sampling Can Bias Multi-Gene Phylogenetic Inferences: The Relationship between Red Algae and Green Plants as a Case Study Mol. Biol. Evol., May 1, 2009; 26(5): 1171 - 1178. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. Hampl, L. Hug, J. W. Leigh, J. B. Dacks, B. F. Lang, A. G. B. Simpson, and A. J. Roger Phylogenomic analyses support the monophyly of Excavata and resolve relationships among eukaryotic "supergroups" PNAS, March 10, 2009; 106(10): 3859 - 3864. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. A. Richards, J. B. Dacks, S. A. Campbell, J. L. Blanchard, P. G. Foster, R. McLeod, and C. W. Roberts Evolutionary origins of the eukaryotic shikimate pathway: gene fusions, horizontal gene transfer, and endosymbiotic replacements. Eukaryot. Cell, September 1, 2006; 5(9): 1517 - 1531. [Abstract] [Full Text] [PDF] |
||||
![]() |
O. Zhaxybayeva, J. P. Gogarten, R. L. Charlebois, W. F. Doolittle, and R. T. Papke Phylogenetic analyses of cyanobacterial genomes: Quantification of horizontal gene transfer events Genome Res., September 1, 2006; 16(9): 1099 - 1108. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. A. Richards and M. van der Giezen Evolution of the Isd11-IscS Complex Reveals a Single {alpha}-Proteobacterial Endosymbiosis for All Eukaryotes Mol. Biol. Evol., July 1, 2006; 23(7): 1341 - 1344. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. J Roger and L. A Hug The origin and diversification of eukaryotes: problems with molecular phylogenetics and molecular clock estimation Phil Trans R Soc B, June 29, 2006; 361(1470): 1039 - 1054. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. G. B. Simpson, Y. Inagaki, and A. J. Roger Comprehensive Multigene Phylogenies of Excavate Protists Reveal the Evolutionary Positions of "Primitive" Eukaryotes Mol. Biol. Evol., March 1, 2006; 23(3): 615 - 625. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Huang, Y. Xu, and J. P. Gogarten The Presence of a Haloarchaeal Type Tyrosyl-tRNA Synthetase Marks the Opisthokonts as Monophyletic Mol. Biol. Evol., November 1, 2005; 22(11): 2142 - 2146. [Abstract] [Full Text] [PDF] |
||||




