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Diversification of unicellular eukaryotes: cryptomonad colonizations of marine and fresh waters inferred from revised 18S rRNA phylogeny

Shalchian-Tabrizi, Kamran; Brate, Jon; Logares, Ramiro LU ; Klaveness, Dag; Berney, Cedric and Jakobsen, Kjetill S. (2008) In Environmental Microbiology 10(10). p.2635-2644
Abstract
The cryptomonads is a well-defined lineage of unicellular eukaryotes, composed of several marine and freshwater groups. However, the evolutionary relationships among these groups are unclear due to conflicting inferences between morphological and molecular phylogenies. Here, we have inferred the evolutionary relationships among marine and freshwater species in order to better understand the importance of the marine-freshwater boundary on the historical diversification patterns of cryptomonads. We have constructed improved molecular phylogenies by taking into account rate variation both across sites and across sequences (covarion substitutions), and by analysing the vast majority of publicly available cryptomonad 18S rRNA sequences and... (More)
The cryptomonads is a well-defined lineage of unicellular eukaryotes, composed of several marine and freshwater groups. However, the evolutionary relationships among these groups are unclear due to conflicting inferences between morphological and molecular phylogenies. Here, we have inferred the evolutionary relationships among marine and freshwater species in order to better understand the importance of the marine-freshwater boundary on the historical diversification patterns of cryptomonads. We have constructed improved molecular phylogenies by taking into account rate variation both across sites and across sequences (covarion substitutions), and by analysing the vast majority of publicly available cryptomonad 18S rRNA sequences and related environmental phylotypes. The resulting phylogenies included 55 sequences, and revealed two novel freshwater cryptomonad clades (CRY1 and CRY2) and a large hidden diversity of cryptomonads. CRY1 was placed deeply within the cryptomonad phylogeny together with all the major freshwater lineages (i.e. Goniomonas and Cryptomonas), while CRY2 was placed within a lineage of marine species identified as Plagioselmis-like with the aid of a new sequence generated from a cultured species. The inferred phylogenies suggest only few successful marine-freshwater transitions over the history of cryptomonads. Most of the transitions seem to have occurred from marine to fresh waters, but re-colonizations of marine habitats have also taken place. This implies that the differences in the biogeophysical conditions between marine and fresh waters constitute a substantial barrier for the cross-colonization of these environments by cryptomonads. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Environmental Microbiology
volume
10
issue
10
pages
2635 - 2644
publisher
Wiley-Blackwell
external identifiers
  • wos:000259147900015
  • scopus:51649088380
ISSN
1462-2920
DOI
10.1111/j.1462-2920.2008.01685.x
language
English
LU publication?
yes
id
cd78d49f-74fa-4aaf-840f-e5a2300a26ec (old id 1246678)
date added to LUP
2008-11-18 14:06:38
date last changed
2017-11-12 03:25:09
@article{cd78d49f-74fa-4aaf-840f-e5a2300a26ec,
  abstract     = {The cryptomonads is a well-defined lineage of unicellular eukaryotes, composed of several marine and freshwater groups. However, the evolutionary relationships among these groups are unclear due to conflicting inferences between morphological and molecular phylogenies. Here, we have inferred the evolutionary relationships among marine and freshwater species in order to better understand the importance of the marine-freshwater boundary on the historical diversification patterns of cryptomonads. We have constructed improved molecular phylogenies by taking into account rate variation both across sites and across sequences (covarion substitutions), and by analysing the vast majority of publicly available cryptomonad 18S rRNA sequences and related environmental phylotypes. The resulting phylogenies included 55 sequences, and revealed two novel freshwater cryptomonad clades (CRY1 and CRY2) and a large hidden diversity of cryptomonads. CRY1 was placed deeply within the cryptomonad phylogeny together with all the major freshwater lineages (i.e. Goniomonas and Cryptomonas), while CRY2 was placed within a lineage of marine species identified as Plagioselmis-like with the aid of a new sequence generated from a cultured species. The inferred phylogenies suggest only few successful marine-freshwater transitions over the history of cryptomonads. Most of the transitions seem to have occurred from marine to fresh waters, but re-colonizations of marine habitats have also taken place. This implies that the differences in the biogeophysical conditions between marine and fresh waters constitute a substantial barrier for the cross-colonization of these environments by cryptomonads.},
  author       = {Shalchian-Tabrizi, Kamran and Brate, Jon and Logares, Ramiro and Klaveness, Dag and Berney, Cedric and Jakobsen, Kjetill S.},
  issn         = {1462-2920},
  language     = {eng},
  number       = {10},
  pages        = {2635--2644},
  publisher    = {Wiley-Blackwell},
  series       = {Environmental Microbiology},
  title        = {Diversification of unicellular eukaryotes: cryptomonad colonizations of marine and fresh waters inferred from revised 18S rRNA phylogeny},
  url          = {http://dx.doi.org/10.1111/j.1462-2920.2008.01685.x},
  volume       = {10},
  year         = {2008},
}