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Chloroplast phylogeographic patterns of Calligonum sect. Pterococcus (Polygonaceae) in arid Northwest China
Author(s) -
Wen Zhibin,
Xu Zhe,
Zhang Hongxiang,
Feng Ying
Publication year - 2016
Publication title -
nordic journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.333
H-Index - 33
eISSN - 1756-1051
pISSN - 0107-055X
DOI - 10.1111/njb.00820
Subject(s) - biology , phylogeography , chloroplast dna , clade , monophyly , polygonaceae , lineage (genetic) , ecology , analysis of molecular variance , intergenic region , botany , haplotype , phylogenetics , genotype , genetics , genome , gene
To understand the impacts of past climatic change and geological events on the evolutionary history of Calligonum sect. Pterococcus , including C. aphyllum, C. rubicundum and C. leucocladum , a total of 128 individuals from 14 populations, mainly from arid Northwest China, were sampled. Two cpDNA intergenic spacer regions ( rpl 32‐ trn L and ycf 6‐ psb M) were sequenced and 11 haplotypes were identified. Levels of genetic differentiation between populations was low in C. rubicundum (F ST = 0.54317, p < 0.001) and C. aphyllum (F ST = 0.55795), while much higher in C. leucocladum (F ST = 0.95800, p < 0.001), possibly as an effct of differences in geographic distributions and habitats. Analysis of molecular variance (AMOVA) revealed that most of the total genetic variations occurred among species (72.97%). Among eleven identified haplotypes, only H1 and H2 were shared between C. aphyllum and C. rubicundum , while nine were private for one of the three species. The eleven identified haplotypes were divided into two major clades, but they did not yield three species‐specific lineages. Calligonum sect. Pterococcus therefore not appeared reciprocally monophyletic, more likely due to incomplete lineage sorting than hybridization. Mismatch distribution analysis suggested that only C. aphyllum has experienced recent demographic expansion. Divergence time among the 11 haplotypes was estimated at between 2.84 Ma and 0.06 Ma. Within the two clades, haplotype divergence began in early Pleistocene and mainly occurred during the middle to late Pleistocene and was most likely triggered by Quaternary climatic oscillations and increasing aridity of the region.