title: Iteration expansion and regional evolution: phylogeography of Dendrobium officinale and four related taxa in southern China.
abstract: The genus Dendrobium was used as a case study to elucidate the evolutionary history of Orchidaceae in the Sino-Japanese Floristic Region (SJFR) and Southeast Asia region. These evolutionary histories remain largely unknown, including the temporal and spatial distribution of the evolutionary events. The present study used nuclear and plastid DNA to determine the phylogeography of Dendrobium officinale and four closely related taxa. Plastid DNA haplotype and nuclear data were shown to be discordant, suggesting reticulate evolution drove the species' diversification. Rapid radiation and genetic drift appeared to drive the evolution of D. tosaense and D. flexicaule, whereas introgression or hybridization might have been involved in the evolution of D. scoriarum and D. shixingense. The phylogeographical structure of D. officinale revealed that core natural distribution regions might have served as its glacial refuges. In recent years, human disturbances caused its artificial migration and population extinction. The five taxa may have originated from the Nanling Mountains and the Yungui Plateau and then migrated northward or eastward. After the initial iteration expansion, D. officinale populations appeared to experience the regional evolutionary patterns in different regions and follow the sequential or rapid decline in gene exchange.
authors.affiliation: College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.|Nanjing Institute for Comprehensive Utilization of Wild Plants, Nanjing 210042, China.
authors.forename: Beiwei
authors.initials: B
authors.lastname: Hou
authors.affiliation: College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Luo
authors.affiliation: College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.|Jiangsu Industrial Technology Research Institute, Nanjing 210042, China.
authors.forename: Yusi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
authors.forename: Zhitao
authors.initials: Z
authors.lastname: Niu
authors.affiliation: College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
authors.forename: Qingyun
authors.initials: Q
authors.lastname: Xue
authors.affiliation: College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Ding
mesh_terms: D002681:China; D018742:DNA, Chloroplast; D021901:DNA, Intergenic; D031667:Dendrobium / Q000145:classification* / Q000235:genetics*; D019143:Evolution, Molecular; D014644:Genetic Variation; D005843:Geography; D006239:Haplotypes; D010802:Phylogeny; D058974:Phylogeography
chemical_list: D018742:DNA, Chloroplast; D021901:DNA, Intergenic