基于ITS序列探讨山茶属金花茶组的系统发育关系

测定了分布于我国的 2 2个山茶属金花茶组的种或变种的nrDNAITS区序列 ,它们的序列长度在 476～ 496之间。GC含量都超过了 70 % ,应用Kimura2 模型计算了序列间的分化程度 ,构建了最大简约树、邻接树和最大似然树 ,分析结果表明 :( 1 )淡黄金花茶、毛籽金花茶、陇瑞金花茶、弄岗金花茶、大样金花茶和凹脉金花茶的关系较近 ;( 2 )小瓣金花茶、小花金花茶、薄叶金花茶、多瓣金花茶、夏石金花茶和龙州金花茶的关系较近。ITS区序列分析结果与AFLP分析结果相近

Phylogenetic relationships of golden camellias (sect.Chrysantha,Camellia) in China:evidence from ITS sequences of nuclear ribosomal DNA

Golden camellias,belonging to the genus Camellia(Theaceae)and distributed in a narrow region of southern China and northern Vietnam,are very famous ornamental plants and useful genetic resources for commercial cultivation,but their phylogenetic relationships have been controversial during the recent decade. In this paper,the nucleotide sequences of the internal transcribed spacer(ITS)of nuclear ribosomal DNA in 22 taxa of the sect.Chrysantha in China and C.sinensis of the sect.Thea as an outgroup were determined by direct dequencing of PCR-amplified DNA fragments. The total length of the ITS1 and ITS2 regions of the sect.Chrysantha in China ranged from 476 to 496 base pairs(bp),and the GC content was over 70% in the 22 taxa. Sequence divergences were estimated using Kimura two-parameter model,and the phylogenetic analysis were performed using the maximum parsimony(MP),the neighbor-joining(NJ),and the maximum likelihood(ML)methods. The ITS data suggest (1)C.longruiensis,C.longgangensis,C.ptilosperma,C.flavida,C.impressinervis and C.grandis are closely related;(2)C.parvipeta,C.multipetala,C.chrysanthoides,C.micriantha,C.xiashiensis,and C.longzhouensis have closed relationship.