Phylogeny of Populus (Salicaceae) based on nucleotide sequences of chloroplast TRNT-TRNF region and nuclear rDNA
Phylogeny of Populus (Salicaceae) based on nucleotide sequences of chloroplast TRNT-TRNF region and nuclear rDNA
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DOI：
10.3732/ajb.91.9.1398
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发表时间：
2004-09-01
影响因子：
3
通讯作者：
Dayanandan, S
中科院分区：
文献类型：
--
作者：
Hamzeh, M;Dayanandan, S
杨属的物种，统称为杨树，广泛分布于北方，并以其生态，经济和进化的重要性而闻名。广泛的种间杂交和高度的形态多样性，在这组提出了困难，确定分类单位的比较进化研究和系统学。为了解杨树属植物的进化关系，并为杨树的系统分类提供理论依据，我们根据叶绿体DNA的3个非编码区（trnL的内含子、trnT-trnL和trnL-trnF的基因间区）和核rDNA的ITS]和ITS 2序列，重建了杨树属植物的系统发育。由此产生的系统发育树表明，在部分Tacamahaca和黑杨属物种之间的多系关系。根据叶绿体DNA序列分析，黑杨与杨属组种亲缘关系较近，而核DNA序列分析表明黑杨与黑杨属组种亲缘关系较近，推测黑杨可能为杂种起源。与此相似，黑杨和四川杨的叶绿体DNA序列与黑杨组的种相似，而核序列与Tacamahaca组的种相似，表明这两种亚洲香脂杨可能是杂种起源。基于核和叶绿体DNA序列数据的系统发育树之间的不一致性表明，在属杨的网状进化。
The species of the genus Populus, collectively known as poplars, are widely distributed over the northern hemisphere and well known for their ecological, economical, and evolutionary importance. The extensive interspecific hybridization and high morphological diversity in this group pose difficulties in identifying taxonomic units for comparative evolutionary studies and systematics. To understand the evolutionary relationships among poplars and to provide a framework for biosystematic classification, we reconstructed a phylogeny of the genus Populus based on nucleotide sequences of three noncoding regions of the chloroplast DNA (intron of trnL and intergenic regions of trnT-trnL and trnL-trnF) and ITS] and ITS2 of the nuclear rDNA. The resulting phylogenetic trees showed polyphyletic relationships among species in the sections Tacamahaca and Aigeiros. Based on chloroplast DNA sequence data, P. nigra had a close affinity to species of section Populus, whereas nuclear DNA sequence data suggested a close relationship between P. nigra and species of the section Aigeiros, suggesting a possible hybrid origin for P. nigra. Similarly, the chloroplast DNA sequences of P. tristis and P. szechuanica were similar to that of the species of section Aigeiros, while the nuclear sequences revealed a close affinity to species of the section Tacamahaca, suggesting a hybrid origin for these two Asiatic balsam poplars. The incongruence between phylogenetic trees based on nuclear- and chloroplast-DNA sequence data suggests a reticulate evolution in the genus Populus.