Molecular Phylogeny of Laminariales (Phaeophyceae) deduced from rRNA gene sequences

为了明确原始海带属（海带）成员间的系统发育关系，对海带属（海带）的18S rRNA基因序列和rRNA基因ITS区进行了研究：nagaipseudochorda， gracilpseudochorda (Pseudochordaceae)；丝线索（索科）；裙带菜（扁豆科）。18S rDNA序列也在单纯髓ophycus simplex中作为外群进行了研究，但其在系统中的顺序位置尚存疑问。两种假索目（P.nagaii和P.gracilis）尽管配子体形态不同，但在系统发育上非常接近。藻藻科的藻藻与Costaria亲缘关系较近，而Chorda filum与Pseudochorda spp、藻藻和Costaria的亲缘关系较远。这些结果与基于其孢子体形态的分类和性引诱物的性质相一致。

Gene sequences of 18S rRNA gene and the ITS region of rRNA gene were studied in the following species of the Laminariales, in order to clarify the phylogenetic relationships among the members of primitive Laminariales (kelps) : Pseudochorda nagaii, Pseudochorda gracilis (Pseudochordaceae) ; Chorda filum (Chordaceae) ; Undaria pinnatifida (Alariaceae). 18S rDNA sequence was also studied in Myelophycus simplex as an out group, whose ordinal systematic position is in question. Two species of Pseudochorda (P.nagaii and P.gracilis) were shown to be phylogenetically very close in spite of their differences in the gametophyte morphology. Undaria and Costaria (Laminariaceae) showed close relationship and Chorda filum showed rather distant position from Pseudochorda spp., Undaria and Costaria. These results agree with the taxonomy based on their sporophyte morphology and the nature is sexual attractants.