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Shao J.-W.,Anhui Normal University | Shao J.-W.,The Key Laboratory of Conservation and Employment of Biological Resources of Anhui | Wang J.,Anhui Normal University | Xu Y.-N.,Anhui Normal University | And 5 more authors.
Botanical Journal of the Linnean Society | Year: 2015

Understanding whether and how different habitats shape population genetics is a fundamental question and a specific goal for evolutionary and conservation biology research. This study examined genetic diversity and gene flow within and between mountain and foothill habitats of Primula merrilliana, an endangered distylous forest herb in eastern China. Eleven population characteristics, including area, size and density variation, from the two habitats were also investigated. Mountain populations had significantly higher mean genetic diversity than foothill populations, which may be explained by stronger self-incompatibility breeding system, more opportunity to use elevational shifts to track suitable sites under conditions of climate change and more heterogeneous environments in the former habitat, rather than by the differences of population size, gene flow and genetic drift intensity between them. Genetic analysis revealed that two distinct lineages, corresponding to the two habitats, diverged at China's 'Last Glaciation' (11700-67500 yr BP), suggesting this divergence was probably triggered by warmer climates during inter- (or post-) glacial periods. Low unidirectional gene flow from mountain to foothill habitats, chiefly by seed dispersal, played a more important role in overall gene flow between habitats than within-habitat gene flow. Within habitats, pollen contributes more substantially to gene flow than seed dispersal, especially in foothill habitats, possibly due to higher individual density and larger population sizes. These results have implications for the conservation in this and similar landscape areas and indicate the need to protect suitable habitats with wide elevational spans and sufficient size to permit ecological and elevational shifts in response to climatic changes. © 2015 The Linnean Society of London. Source

Li X.-H.,Anhui Normal University | Shao J.-W.,Anhui Normal University | Shao J.-W.,Key Laboratory of Conservation and Employment of Biological Resources of Anhui | Lu C.,Anhui Normal University | And 2 more authors.
Journal of Systematics and Evolution | Year: 2012

Pteroceltis tatarinowii Maxim. (Ulmaceae), one of the most widespread temperate canopy trees in mainland China, is the sole representative of the genus Pteroceltis. To illuminate the biogeographic and demographic history of this temperate tree species, we carried out a survey of chloroplast DNA sequence variation (trnS-trnG and psbA-trnH) within and among 28 populations (284 individuals in total) representing most of the distributional range of the species. Based on a total of 13 haplotypes identified, P. tatarinowii was found to harbor surprisingly high levels of haplotype and nucleotide diversity (h T = 0.71; πT = 2.83 × 10-3), possibly associated with its long evolutionary history and wide-scale geographical distribution. Significant chloroplast DNA population subdivision was detected (GST = 0.898; NST = 0.938), suggesting low levels of recurrent gene flow through seeds among populations and significant phylogeographical structure (NST > GST, P <0.05). The ancestral haplotypes show clear-cut geographical distribution, and most regions possess a unique set of haplotypes, suggesting multiple potential refugia of the species occurring in montane areas of South China. The haplotype mismatch distributions analysis indicates that populations from North China underwent a spatial northward expansion, which might reflect one of the repeated Pleistocene south-to-north shifts of temperate deciduous forest in North China following cold periods. © 2012 Institute of Botany, Chinese Academy of Sciences. Source

Xiang X.-L.,Anhui Normal University | Xiang X.-L.,Key Laboratory of Biotic Environment and Ecological Safety in Anhui Province | Xi Y.-L.,Anhui Normal University | Xi Y.-L.,Key Laboratory of Biotic Environment and Ecological Safety in Anhui Province | And 6 more authors.
Molecular Phylogenetics and Evolution | Year: 2011

Elucidating the evolutionary patterns and processes of extant species is an important objective of any research program that seeks to understand population divergence and, ultimately, speciation. The island-like nature and temporal fluctuation of limnetic habitats create opportunities for genetic differentiation in rotifers through space and time. To gain further understanding of spatio-temporal patterns of genetic differentiation in rotifers other than the well-studied Brachionus plicatilis complex in brackish water, a total of 318 nrDNA ITS sequences from the B. calyciflorus complex in freshwater were analysed using phylogenetic and phylogeographic methods. DNA taxonomy conducted by both the sequence divergence and the GMYC model suggested the occurrence of six potential cryptic species, supported also by reproductive isolation among the tested lineages. The significant genetic differentiation and non-significant correlation between geographic and genetic distances existed in the most abundant cryptic species, BcI-W and Bc-SW. The large proportion of genetic variability for cryptic species Bc-SW was due to differences between sampling localities within seasons, rather than between different seasons. Nested Clade Analysis suggested allopatric or past fragmentation, contiguous range expansion and long-distance colonization possibly coupled with subsequent fragmentation as the probable main forces shaping the present-day phylogeographic structure of the B. calyciflorus species complex. © 2011 Elsevier Inc. Source

Xiang X.-L.,Anhui Normal University | Xiang X.-L.,Key Laboratory of Biotic Environment and Ecological Safety in Anhui Province | Xi Y.-L.,Anhui Normal University | Xi Y.-L.,Key Laboratory of Biotic Environment and Ecological Safety in Anhui Province | And 6 more authors.
Molecular Ecology | Year: 2011

Spatio-temporal patterns and processes of genetic differentiation in passively dispersing zooplankton are drawing much attention from both ecologists and evolutionary biologists. Two opposite phylogeographical scenarios have already been demonstrated in rotifers, which consist of high levels of genetic differentiation among populations even on small geographical scales on the one hand and the traditionally known cosmopolitanism that is associated with high levels of gene flow and long-distance dispersal via diapausing stages on the other hand. Here, we analysed the population genetic structure and the phylogeography of the Brachionus calyciflorus species complex in eastern China. By screening a total of 318 individuals from ten locations along a 2320-km gradient and analysing samples from two growing seasons, we aimed at focusing on both small- and large-scale patterns. We identified eight cryptic species and verified species status of two of these by sexual reproduction tests. Samples in summer and winter yielded different cryptic species. The distribution patterns of these genetically distinct cryptic species were diverse across eastern China, from full cosmopolitanism to local endemism. The two most abundant cryptic species BcWIII and BcSW showed a pattern of strong genetic differentiation among populations and no significant isolation by distance. Long-distance colonization, secondary contact and recent range expansion are probably responsible for the indistinct pattern of isolation by distance. Our results suggest that geographical distance is more important than temporal segregation across seasons in explaining population differentiation and the occurrence of cryptic species. We explain the current phylogeographical structure in the B. calyciflorus species complex by a combination of recent population expansion, restricted gene flow, priority effects and long-distance colonization. © 2011 Blackwell Publishing Ltd. Source

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