Algae. 2007; 22(1): 1-10.
Molecular Phylogeny of the Genera Staurastrum and Staurodesmus (Zygnematophyceae, Streptophyta) Based on Nuclear (18S rDNA) and Chloroplast Gene (atpB) Sequences
Byeong Ryeol Moon and Ok-Min Lee*
Department of Biology, Kyonggi University, Suwon 443-760, Korea
ABSTRACT
To gain insights into the phylogenetic relationships of genus Staurastrum and Staurodesmus, we analyzed nuclearencoded small subunit rDNA of 82 strains, and chloroplast atpB gene sequences of 44 strains belonging to three genera (Staurastrum, Staurodesmus, Cosmarium). Excluding the Staurastrum muticum and S. orbiculare, forty five strains of genus Staurastrum formed a well supported clade. It was shown that with no cell wall sculpture and processes, these two species have a strong phylogenetic relationship with genus Staurodesmus. Therefore, it is strongly recommended to transfer Staurastrum without processes and cell wall sculpture into Staurodesmus. S. obsoletus is a taxa that is transferred from Cosmarium. But, from this study, it has shown a phylogenetic relationship with Cosmarium. Therefore, this species is strongly recommended to transfer back to Cosmarium instead of Staurodesmus. As it was studied before, genus Staurastrum has shown monophyletic. Since the genus Staurodesmus groups with Cosmarium, they were shown to be polyphyletic.
Keywords :
atpB, 18S rDNA, Staurastrum, Staurodesmus
