title: Should I stay or should I go: biogeographic and evolutionary history of a polyploid complex (Chrysanthemum indicum complex) in response to Pleistocene climate change in China.
abstract: Quaternary climatic oscillations greatly influenced the distribution and pattern of biodiversity in the Northern Hemisphere. Here we examine how such oscillations in South East Asia may have affected the demographic and evolutionary history of a polyploid plant complex associated with semi-dry habitats. We analyzed plastid and nuclear ribosomal DNA (rDNA) internal transcribed spacer (ITS) sequence variation within the Chrysanthemum indicum complex (Asteraceae), which comprises diploid and polyploid plants distributed throughout China. In total, 368 individuals from 47 populations across the geographical range of the complex were analyzed. We show that the relatively widespread tetraploid form of C. indicum expanded its range southward in the Pleistocene, possibly during the most recent or previous glacial period when conditions became drier and forests retreated in southern China. In marked contrast, diploid and other polyploid members of the complex failed to expand their ranges at these times or have since undergone range contractions in contrast to tetraploid C. indicum. We conclude that hybridization and gene flow between taxa occurred frequently during the evolutionary history of the complex, causing considerable sharing of chlorotypes and ITS types. Nevertheless, taxa within ploidy levels could be largely distinguished according to chlorotype and/or ITS type.
authors.affiliation: College of Life Sciences, Peking University, Beijing, 100871, China.|School of Biology, University of St Andrews, Mitchell Building, St Andrews, Fife, KY16 9TH, UK.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: College of Life Sciences, Peking University, Beijing, 100871, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wan
authors.affiliation: Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, 100875, China.
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Guo
authors.affiliation: School of Biology, University of St Andrews, Mitchell Building, St Andrews, Fife, KY16 9TH, UK.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Abbott
authors.affiliation: College of Life Sciences, Peking University, Beijing, 100871, China.
authors.forename: Guang-Yuan
authors.initials: GY
authors.lastname: Rao
mesh_terms: D005075:Biological Evolution; D002681:China; D031202:Chrysanthemum / Q000235:genetics*; D057231:Climate Change; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D014644:Genetic Variation; D005843:Geography; D008969:Molecular Sequence Data; D010802:Phylogeny; D011123:Polyploidy; D018401:Sample Size; D013997:Time Factors
chemical_list: D021903:DNA, Ribosomal Spacer
keywords: Chrysanthemum indicum complex; Quaternary climatic oscillation; biogeography; hybridization; polyploidy; range expansion