title: Phylogeny reconstruction and hybrid analysis of populus (Salicaceae) based on nucleotide sequences of multiple single-copy nuclear genes and plastid fragments.
abstract: Populus (Salicaceae) is one of the most economically and ecologically important genera of forest trees. The complex reticulate evolution and lack of highly variable orthologous single-copy DNA markers have posed difficulties in resolving the phylogeny of this genus. Based on a large data set of nuclear and plastid DNA sequences, we reconstructed robust phylogeny of Populus using parsimony, maximum likelihood and Bayesian inference methods. The resulting phylogenetic trees showed better resolution at both inter- and intra-sectional level than previous studies. The results revealed that (1) the plastid-based phylogenetic tree resulted in two main clades, suggesting an early divergence of the maternal progenitors of Populus; (2) three advanced sections (Populus, Aigeiros and Tacamahaca) are of hybrid origin; (3) species of the section Tacamahaca could be divided into two major groups based on plastid and nuclear DNA data, suggesting a polyphyletic nature of the section; and (4) many species proved to be of hybrid origin based on the incongruence between plastid and nuclear DNA trees. Reticulate evolution may have played a significant role in the evolution history of Populus by facilitating rapid adaptive radiations into different environments.
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, People's Republic of China.
authors.forename: Zhaoshan
authors.initials: Z
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, People's Republic of China.
authors.forename: Shuhui
authors.initials: S
authors.lastname: Du
authors.affiliation: Forest and Evolutionary Genomics Laboratory, and the Centre for Structural and Functional Genomics, Biology Department, Concordia University, Montreal, Quebec, Canada.
authors.forename: Selvadurai
authors.initials: S
authors.lastname: Dayanandan
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, People's Republic of China.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, People's Republic of China.
authors.forename: Yanfei
authors.initials: Y
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, People's Republic of China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Zhang
mesh_terms: D002678:Chimera; D018628:Gene Dosage; D017343:Genes, Plant; D008969:Molecular Sequence Data; D010802:Phylogeny; D018087:Plastids / Q000235:genetics*; D032107:Populus / Q000145:classification* / Q000235:genetics*