title: Conservation genetics and phylogeography of endangered and endemic shrub Tetraena mongolica (Zygophyllaceae) in Inner Mongolia, China.
abstract: BACKGROUND
  Tetraena mongolica (Zygophyllaceae), an endangered endemic species in western Inner Mongolia, China. For endemic species with a limited geographical range and declining populations, historical patterns of demography and hierarchical genetic structure are important for determining population structure, and also provide information for developing effective and sustainable management plans. In this study, we assess genetic variation, population structure, and phylogeography of T. mongolica from eight populations. Furthermore, we evaluate the conservation and management units to provide the information for conservation.
  
  
  RESULTS
  Sequence variation and spatial apportionment of the atpB-rbcL noncoding spacer region of the chloroplast DNA were used to reconstruct the phylogeography of T. mongolica. A total of 880 bp was sequenced from eight extant populations throughout the whole range of its distribution. At the cpDNA locus, high levels of genetic differentiation among populations and low levels of genetic variation within populations were detected, indicating that most seed dispersal was restricted within populations.
  
  
  CONCLUSIONS
  Demographic fluctuations, which led to random losses of genetic polymorphisms from populations, due to frequent flooding of the Yellow River and human disturbance were indicated by the analysis of BEAST skyline plot. Nested clade analysis revealed that restricted gene flow with isolation by distance plus occasional long distance dispersal is the main evolutionary factor affecting the phylogeography and population structure of T. mongolica. For setting a conservation management plan, each population of T. mongolica should be recognized as a conservation unit.
authors.affiliation: Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China.
authors.forename: Xue-Jun
authors.initials: XJ
authors.lastname: Ge
authors.forename: Chi-Chuan
authors.initials: CC
authors.lastname: Hwang
authors.forename: Zin-Huang
authors.initials: ZH
authors.lastname: Liu
authors.forename: Chi-Chun
authors.initials: CC
authors.lastname: Huang
authors.forename: Wei-Hsiang
authors.initials: WH
authors.lastname: Huang
authors.forename: Kuo-Hsiang
authors.initials: KH
authors.lastname: Hung
authors.forename: Wei-Kuang
authors.initials: WK
authors.lastname: Wang
authors.forename: Tzen-Yuh
authors.initials: TY
authors.lastname: Chiang
mesh_terms: D002681:China; D003710:Demography; D056727:Endangered Species; D051456:Gene Flow; D014644:Genetic Variation; D005828:Genetics, Population; D058974:Phylogeography; D016415:Sequence Alignment; D028461:Zygophyllaceae / Q000235:genetics*