title: Divergent Population Genetic Structure of the EndangeredHelianthemum(Cistaceae) and Its Implication to Conservation in Northwestern China.
abstract: Population genetic studies provide a foundation for conservation planning, especially for endangered species. Three chloroplast SSRs (mtrnSf-trnGr, mtrnL2-trnF, andmtrnL5-trnL3) and the internal transcribed spacer were used to examine the population structure ofHelianthemumin northwestern China. A total of 15 populations of the genus were collected. Nine chloroplast haplotypes and two nuclear genotypes were detected. Both the nuclear and chloroplast data showed two lineages inHelianthemum songaricum, respectively, distributed in Yili Valley and western Ordos Plateau. A total of 66.81% (p< 0.001) of the genetic variation was supported by this lineage split. A Mantel test showed a significant correlation between genetic distance and geographical distance (r= 0.937,p< 0.001). Based on genetic analyses, cpSSRs data support strong genetic divergence between regions. We speculate that the climate change during the late Tertiary and early Quaternary isolatedH. songaricuminto their current distribution, resulting in interruption of gene flow, leading to isolation and genetic divergence between the two regions. Meanwhile, possible selfing would increase genetic drift in small fragmented populations, that might account for the observed genetic divergence in both regions. Given the loss of genetic diversity and genetic divergence in small populations ofHelianthemumin northwestern China immediate conservation management steps should be taken on the species.
authors.affiliation: Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences Urumqi, China.
authors.forename: Zhihao
authors.initials: Z
authors.lastname: Su
authors.affiliation: USDA Forest Service, Rocky Mountain Research Station Provo, UT, USA.
authors.forename: Bryce A
authors.initials: BA
authors.lastname: Richardson
authors.affiliation: Library, Xinjiang Normal University Urumqi, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhuo
authors.affiliation: Shanghai Chenshan Plant Science Research Center, Shanghai Chenshan Botanical Garden, Chinese Academy of Sciences Shanghai, China.
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Jiang
keywords: Helianthemum; Yili Valley; conservation implication; genetic diversity; genetic structure; western Ordos Plateau