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Phylogeny and molecular evolution of green algae

Ellen Cocquyt UGent (2009)
abstract
Green algae exhibit a remarkable cytological diversity ranging from unicellular microscopic algae with a single nucleus, over multicellular filaments and foliose blades, to siphonocladous and siphonous life forms that are essentially composed of many cells or a single giant cell containing countless nuclei. Accurate reconstruction of the phylogenetic relationships of this diverse group is paramount to understanding the evolution of multicellularity and cytological layouts. Because ribosomal RNA and plastid genes have failed to resolve relationships among the major groups with confidence, we have generated data for 7 nuclear housekeeping genes. We present a phylogeny based on analyses (ML and BI) of these seven genes, SSU nrDNA and two plastid markers with carefully chosen partitioning strategies and models of sequence evolution. We obtained high support across the topology of the Chlorophyta, show the monophyly of the Ulvophyceae, Trebouxiophyceae and Chlorophyceae (UTC) classes and reveal a sister relationship between Chlorophyceae and Ulvophyceae. The inferred relationships provide novel insights into the evolution of multicellularity and multinucleate cells in the Ulvophyceae. Guided by this improved green algal phylogenetic tree, we address various topics relating to molecular evolution of the Chlorophyta. The distribution of elongation factor genes EFL and EF1-alpha, reassignment of stop codons to glutamine, a relatively even use of synonymous codons and high rates of molecular evolution of the ribosomal RNA indicate that profound changes occurred to the translational system of the Ulvophyceae.
Please use this url to cite or link to this publication:
author
promoter
UGent
organization
year
type
dissertation (composite)
subject
keyword
single-copy nuclear genes, green algae, elongation factor genes, non-canonical genetic code, codon usage bias, GC content, molecular phylogenetics
pages
168 pages
defense location
Auditorium Valère Billiet, Krijgslaan 281, building S8
defense date
2009-06-18 16:00
language
English
UGent publication?
yes
classification
D1
id
712285
handle
http://hdl.handle.net/1854/LU-712285
alternative location
http://lib.ugent.be/fulltxt/RUG01/001/376/342/RUG01-001376342_2010_0001_AC.pdf
date created
2009-07-01 16:45:15
date last changed
2009-07-28 10:46:04
@phdthesis{712285,
  abstract     = {Green algae exhibit a remarkable cytological diversity ranging from unicellular microscopic algae with a single nucleus, over multicellular filaments and foliose blades, to siphonocladous and siphonous life forms that are essentially composed of many cells or a single giant cell containing countless nuclei. Accurate reconstruction of the phylogenetic relationships of this diverse group is paramount to understanding the evolution of multicellularity and cytological layouts. Because ribosomal RNA and plastid genes have failed to resolve relationships among the major groups with confidence, we have generated data for 7 nuclear housekeeping genes. We present a phylogeny based on analyses (ML and BI) of these seven genes, SSU nrDNA and two plastid markers with carefully chosen partitioning strategies and models of sequence evolution. We obtained high support across the topology of the Chlorophyta, show the monophyly of the Ulvophyceae, Trebouxiophyceae and Chlorophyceae (UTC) classes and reveal a sister relationship between Chlorophyceae and Ulvophyceae. The inferred relationships provide novel insights into the evolution of multicellularity and multinucleate cells in the Ulvophyceae. Guided by this improved green algal phylogenetic tree, we address various topics relating to molecular evolution of the Chlorophyta. The distribution of elongation factor genes EFL and EF1-alpha, reassignment of stop codons to glutamine, a relatively even use of synonymous codons and high rates of molecular evolution of the ribosomal RNA indicate that profound changes occurred to the translational system of the Ulvophyceae.},
  author       = {Cocquyt, Ellen},
  keyword      = {single-copy nuclear genes,green algae,elongation factor genes,non-canonical genetic code,codon usage bias,GC content,molecular phylogenetics},
  language     = {eng},
  pages        = {168},
  school       = {Ghent University},
  title        = {Phylogeny and molecular evolution of green algae},
  url          = {http://lib.ugent.be/fulltxt/RUG01/001/376/342/RUG01-001376342\_2010\_0001\_AC.pdf},
  year         = {2009},
}

Chicago
Cocquyt, Ellen. 2009. “Phylogeny and Molecular Evolution of Green Algae.”
APA
Cocquyt, E. (2009). Phylogeny and molecular evolution of green algae.
Vancouver
1.
Cocquyt E. Phylogeny and molecular evolution of green algae. 2009.
MLA
Cocquyt, Ellen. “Phylogeny and Molecular Evolution of Green Algae.” 2009 : n. pag. Print.