The nuclear encoded internal transcribed spacer (ITS) region and the plastid encoded trn L-F region were sequenced for 41 species of the Aceraceae, representing both genera Acer and Dipteronia, to reconstruct phylogeny of this family, especially within Acer. The analyses were performed in separate and combined sequence data sets, with the Sapindaceae and Hippocastanaceae being selected as outgroups. It was indicated that the Aceraceae was monophyletic and D. sinensis was basal to the rest of the family but the two genera of it might be not monophyletic because Dipteronia dyerana was nested within Acer. The result inferred from the combined data showed greater resolution within Acer than that from the two separate data sets. The monophyly of most sections in Xu's system (1996) were supported with high bootstrap values, and some relationships between (or among) sections were also inferred, such as sect. Palmata and sect. Microcarpa; sect. Platanoidea, sect. Lithocarpa and sect. Macrophylla; sect. Integrifolia, sect. Trifoliata and sect. Pentaphylla; and sect. Acer, sect. Goniocarpa and sect. Saccharina (sensu Ogata). However, the sectional status and circumscriptions of some of the above-mentioned sections should be further adjusted. It seemed that the Xu's delimitations of sect. Rubra and sect. Saccharodendran should be revaluated.
The molecular composition and evolution of the chalcone synthase (CHS) gene family from five species in Camellia (Theaceae) are explored in this study. Sixteen CHS exon 2 from four Camellia species were amplified from total DNA by PCR method. Three sequences of the fifth species in Camellia and two sequences of Glycine max as the designated outgroups were obtained from GenBank. Our results indicated that CHS gene family in Camellia was differentiated to three subfamilies (A, B, C) during the evolutionary history with six groups (A1, A2, A3, BI, B2, C). Among them, only group A2 was possessed by all five species in this study. However, the other five groups were detected only in some species of the plants studied. All members of CHS gene family in this study had high sequence similarity, more than 90% among the members in the same subfamily and more than 78% among different subfamilies at nucleotide level., According to the estimated components of amino acids, the function of CHS genes in Camellia had been diverged. The nucleotide substitutions of the different groups were not identical. Based on phylogenetic analyse inferred from sequences of CHS genes and their deduced amino acid sequences, we concluded that the CHS genes with new function in this genus were evolved either by mutations on several important sites or by accumulation of the mutations after the gene duplication. A further analysis showed that the diversification of CHS genes in Camellia still occurred recently, and the evolutionary models were different to some extant among different species. So we assumed that the different evolutionary models resulted from the impacts of variable environmental elements after the events of speciation.
