MOLECULAR SYSTEMATICS OF ECTOCARPUS AND KUCKUCKIA (ECTOCARPALES, PHAEOPHYCEAE) INFERRED FROM PHYLOGENETIC ANALYSIS OF NUCLEAR‐ AND PIASTTD‐ENCODED DNA SEQUENCES

Abstract

The phylogeny of Ectocarpus and Kuckuckia strains representing widely separated populations ?om both hemispheres was infmed from sequence analysis of the internal transcribed spacers of the nuclear ribosomal DNA (ITS 1-5.8s-ITS 2) and Lhe spucer regton i n the plastid-encoded ribulos~bis-phosphate-carboxylase (RUBISCO) cistron (partial rbc L-spac:er+artial rbcS) . Both sequences resulted in matching phylogenies, with the RUBISCO spacer regzon being most i r~o~a t i v~ at the h e 1 of genera and .specie.s and the i n t m a l transm'bed spacer sequences at the level of species and populations. Three major clades were -formed f q strains previously described morphology and physiolob us Kuckuckia, E. fasciculatus, and E. siliculosus, con$min,g the validity of the.w taxa. Ectocarpus and Kuckuckia are regarded as sibling taxa with respect to the outgroup .species Feldmannia simplex, Hincksia mitchelliae, and Pilayella littoralis. The clade f m e d by .sexual E. siliculosus .strains and most asexual Ectocarpus strains was subdivided into several clades that are consistent with geographical races within E. siliculosus. The inferred phylogeny of Ectocarpus corresponds generally with resu1t.r from cro.ss-f)rrilization expm'ment.s, mmphology, and lipid analysis. A hypothesis on the origzn and dispersal of E. siliculosus suggests several natural dispersal events during periods of global cooling as well as recent and po.rsibly anthropogenic dispmsal event.$.

Molecular systematics of the genera <i>Laurencia, Osmundea</i> and <i>Palisada</i> (Rhodophyta) from the Canary Islands - Analysis of rDNA and RUBISCO spacer sequences

“…The two species are morphologically very similar with the exception that L. viridis is green in color and L. thyrsifera reddish/purple. This high degree of conservation of primary sequence of the RUBISCO spacer has been noted in other algae (Valentin & Zetche, 1990;Destombe & Douglas, 1991;Stache-Grain & al., 1997) and it has been hypothesized that this conservation of sequence is as a result of the secondary structures in the plastid spacer perhaps having a role in tRNA maturation (Destombe & Douglas, 1991). The AT content …”

“…This spacer region has been utilized in taxo-nomic and systematic studies of algae (Destombe & Douglas, 1991;Stache-Grain & al., 1997).…”

“…Interspecific and intraspecific sequence variation of these regions has been examined in plants (Baldwin, 1992), fungi (O'Donnell, 1992), diatoms (Zechman & al., 1994), green algae Bakker & al., 1995), ahermatypic corals (Beauchamp & Powers, 1996) and red algae (Steane & al., 1991). rDNA has also been utilised for systematic and taxonomic studies of algae Rumpf & al., 1996;Stache-Grain & al., 1997). and Stache-Grain & al.…”

Phylogeny of Alariaceae, Laminariaceae, and Lessoniaceae (Phaeophyceae) Based on Plastid-Encoded RuBisCo Spacer and Nuclear-Encoded ITS Sequence Comparisons

“…Regions of ambiguous alignment (a total of 23 positions) were exclued for subsequent phylogenetic analyses. The boundaries of the RuBisCo spacer and the flanking coding regions were determined by comparison to several published sequences obtained from a variety of brown algae (Assali et al, 1990;Stache-Crain et al, 1997;Lee et al, 1999;Yoon and Boo, 1999). The RuBisCo spacer sequences were evaluated for several standard descriptive parameters, including size, percent G ϩ C content, percent pairwise divergence, percent parsimony-informative sites, gamma shape parameter, and proportion of invariable sites using PAUP* v4.0b8 (Swofford, 2001).…”

Conservation and polymorphism of mitochondrial intergenic sequences in brown algae (Phaeophyceae)

“…In brown algae, particularly poorly resolved evolutionary relationships due to recent, rapid 'crown' radiation of the Phaeophyceae (de Reviers & Rousseau, 1999;Draisma et al, 2001) and low intraspecific resolution of the plastid-coded RuBisCO intergenic spacer (e.g. Stache-Crain et al, 1997;Yoon & Boo, 1999;Kraan & Guiry, 2000;Kraan et al, 2001) have probably contributed to the relative paucity of phylogeographic studies in this group, particularly compared with green and red seaweeds (e.g. Gabrielson et al, 2002;Zuccarello & West, 2002;Meusnier et al, 2004;Provan et al, 2005;Zuccarello et al, 2005).…”