Genetic and geographical structure of boreal plants in their southern range: phylogeography of Hippuris vulgaris in China.

Qixiang Lu,Xinwei Xu,Dan Yu,Jinning Zhu

doi:10.1186/s12862-016-0603-6

Abstract

BackgroundOur current understanding of the evolutionary history of boreal and arctic-alpine plants in their southern range in Asia remains relatively poor. Using three cpDNA non-coding regions and nine nuclear microsatellite (nSSR) loci, we examine the phylogeographic pattern in a broad geographic sampling of the boreal plant Hippuris vulgaris to infer its dispersal and diversification in China. In addition, the species distributions at the Last Glacial Maximum (LGM) and at present were predicted using ecological niche modeling (ENM).ResultsThe cpDNA results revealed two distinct lineages, A and B. A is restricted to Northeast China; B is distributed in Northwest China, the Qinghai-Tibet Plateau (QTP) and North and Northeast (NNE) China; and A and B diverged ca. 1.36 Ma. The nSSR data revealed two genetic clusters corresponding to the two cpDNA lineages and nonreciprocal hybridization with lineage A as the maternal lineage in Northeast China. Cluster B further divided into three subclusters: I, mainly in NNE China and the northeastern border of the QTP; II, in Northwest China and the QTP; and III, on the QTP. ENM predicted a marked range shift on the QTP at the LGM, retreating from the platform to the northeast and southeast edges.ConclusionsHippuris vulgaris probably diverged into lineages A and B in high latitudes and then immigrated into Northeast China and Northwest China, respectively. Lineage A persisted and diversified in Northeast China. Lineage B reached the QTP during the mid-Pleistocene, diversified in that region due to the influence of climatic oscillations, migrated into Northeast China and subsequently hybridized with lineage A. Our findings give empirical evidence that boreal plants display complex evolutionary history in their southern range in Asia and provide new insights into the evolution of boreal and arctic-alpine plants.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-016-0603-6) contains supplementary material, which is available to authorized users.

Highlights

Our current understanding of the evolutionary history of boreal and arctic-alpine plants in their southern range in Asia remains relatively poor
Group A was restricted to mountainous areas in Northeast China
Group A was found in 28 populations, with haplotype A3 widespread and present in 21 populations, haplotypes A4 and A12 each found in two populations, and other haplotypes each restricted to a single population (Fig. 2a)

Summary

Introduction

Our current understanding of the evolutionary history of boreal and arctic-alpine plants in their southern range in Asia remains relatively poor. Climatic oscillations in the Quaternary have greatly affected the distribution and abundance of boreal and arctic species [1]. These species have undergone major range shifts with the advances and retreats of ice sheets. Phylogeographic studies with a broader geographic sampling in Asia are necessary to better elucidate evolutionary histories of boreal and arctic-alpine plants. China provides suitable habitats for many boreal and arctic-alpine plant species in their southern range, including the Qinghai-Tibetan Plateau (QTP) and mountain ranges in Northwest China and Northeast China [14]. Infra-specific lineage divergence in boreal and arcticalpine plants might occur in this region

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