PHYLOGENY OF ALARIACEAE, LAMINAR‐IACEAE, AND LESSONIACEAE (PHAEOPHYCEAE) BASED ON PLASTID‐ENCODED RUBISCO SPACER AND NUCLEAR‐ENCODED ITS SEQUENCE COMPARISONS

Yoon, H. S. 1,2 , Boo, S M. 1 & Bhattacharya, D. 21 Department of Biology, Chungnam National University, Daejon 305‐764, Korea; 2 Department of Biological Sciences, University of Iowa, 239 Biology Building, Iowa City, Iowa 52242‐1324, USA Concatenated sequences from the plastid‐encoded RuBisCo spacer and nuclear‐encoded rDNA ITS region of the Alariaceae, Laminariaceae, and Lessoniaceae as currently recognized were used to determine the phylogeny of the advanced kelps (Phaeophyceae). Our analyses indicate that all taxa currently assigned to the Alariaceae, Laminariaceae, and Lessoniaceae form a well‐supported monophyletic lineage. The phylogenetic analyses showed that the kelps form eight independent clades (Egregia, Laminaria, Hedophyllum, Macrocystis, Alaria, Agarum, Ecklonia, and Lessonia) with strong bootstrap support. These clades conform to the tribes of the current morphological classification system of the advanced kelps. The interrelationships among the eight lineages were suggesting a rapid, possible simultaneous radiation in the history of kelps with Egregia likely diverging earliest and being the sister to the other genera. Our analyses also indicate that Kjellmaniella and Laminaria do not form a monophyletic group. We will discuss the evolutionary history of the advanced kelps and provide a new framework for establishing the systematics of these commercially important brown algae.