A Molecular Analysis of Origin and Early Evolution of Angiosperms

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To clarify a phylogeny and early evolution of angiosperms, phylogenetic analysis based on atpB and rbcL gene sequence was done. For representative of some clades in angiopserms, Magnolia, Persea, Nymphaea, Nicotian and Oryza were selected for the study. Ceratophyllum which was considered as most primitive lineage of angiosperms in recet molecular study (Chase et al. 1993) is also included in the study. For an outgroup Pinus thunbergii was sclccted for rooting a tree.The phylogenetic tree obtained based on rbcL sequences and that based on atpB have different topology each other. In both tree, Ceratophyllum did not come to a basal position. These trees are also different from the result of global analysis of angiosperm phylogeny based on rbcL gene (Chase et al.). For elucidate confidence limit, bootstrap alaysis was performed in both data set. As a result confidence of these trees were rather low, indicating lack of enough information. For using more information, two data sets, rbcL and atpB,were connected and analysis. As a result the tree with a topology ((((Nymphaea, Ceratophyllum) , Nicotiana), (Magnolia, Persea)) , Oryza) was obtained. However, confidence of this tree is also not enough and need more information of other genes to clarify the phylogeny.