title: Phylogeography of Libanotis buchtormensis (Umbelliferae) in Disjunct Populations along the Deserts in Northwest China.
abstract: In Northwest China, aridification and desert expansion play significant roles in promoting desert plant diversification and speciation. However, to date, little is known about the effects of the desert barrier on the population structure of montane, non-desert species in the area. In this study, we sequenced chloroplast DNA regions (trnL-trnF and trnS-trnG) and a nuclear gene (rpb2) to investigate the population differentiation and phylogeographical history of Libanotis buchtormensis, a perennial montane species possessing a disjunct distribution at the periphery of the central desert. In total, 23 chloroplast haplotypes and 24 nuclear haplotypes were recovered from the 21 natural populations and six hebarium specimens. Phylogenetic analysis based on the combined plastid and nuclear dataset revealed two distinct lineages of L. buchtormensis, which inhabit the disjunct areas on both sides of the desert zone. The molecular dating analysis indicated that the divergence between the southeastern and the northwestern populations occurred in the middle Pleistocene, concomitantly with the desert expansion. The geographical vicariance likely contributed to the present disjunct distribution of L. buchtormensis across the deserts in Northwest China. Populations in the southeastern region may have migrated from the northwestern region, and seem to be a peripheral distribution of L. buchtormensis.
authors.affiliation: College of Forestry, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.affiliation: College of Forestry, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Xianzhi
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Plateau Flower Research Centre, Qinghai University, Xining, Qinghai, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Tang
authors.affiliation: College of Landscape Architecture and Arts, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Liu
authors.affiliation: College of Life Science, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Langran
authors.initials: L
authors.lastname: Xu
authors.affiliation: College of Landscape Architecture and Arts, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Wang
mesh_terms: D019661:Apiaceae / Q000145:classification* / Q000235:genetics*; D002681:China; D018742:DNA, Chloroplast / Q000235:genetics; D018744:DNA, Plant; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes; D008962:Models, Theoretical; D010802:Phylogeny; D058974:Phylogeography; D018087:Plastids / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D018742:DNA, Chloroplast; D018744:DNA, Plant