Achyut Kumar Banerjee1, Hui Feng1, Yuting Lin1, Zhuangwei Hou1, Weixi Li1, Huiyu Shao1, Zida Luo1, Wuxia Guo1,2, Yelin Huang3. 1. State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, Guangdong, China. 2. Department of Bioengineering, Zhuhai Campus of Zunyi Medical University, Zhuhai, 519041, Guangdong, China. 3. State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, Guangdong, China. lsshyl@mail.sysu.edu.cn.
Abstract
MAIN CONCLUSION: This study identified the historical geoclimatic factors which caused low genetic diversity and strong phylogeographic structure in a cryptoviviparous mangrove. The phylogeographic pattern was used to suggest conservation actions. Phylogeographic studies are used to understand the spatial distribution and evolution of genetic diversity, and have major conservation implications, especially for threatened taxa like the mangroves. This study aimed to assess the phylogeographic pattern of Aegiceras corniculatum, a cryptoviviparous mangrove, across its distribution range in the Indo-West Pacific (IWP) region. We genotyped 398 samples, collected from 37 populations, at four chloroplast DNA (cpDNA) loci, and identified the influence of historical processes on the contemporary population structure of the species. Low genetic diversity at the population level was observed. The evolutionary relationship between 12 cpDNA haplotypes suggested a strong phylogeographic structure, which was further validated by the clustering algorithms and proportioning of maximum variation among hierarchical population groups. The magnitude and direction of historical gene flow indicated that the species attained its wide distribution from its likely ancestral area of the Malay Archipelago. The divergence time estimates of the haplotypes indicated that the geoclimatic changes during the Pleistocene, especially the glacial sea-level changes and emergence of landmasses, hindered genetic exchange and created genetic differentiation between the phylogenetic groups. The species overwintered the last glacial maxima in multiple refugia in the IWP, as identified by the environmental niche modelling. Overall, our findings indicated that ancient glacial vicariance had influenced the present genetic composition of A. corniculatum, which was maintained by the current demographic features of this region. We discussed how these findings can be used to prioritize areas for conservation actions, restore disturbed habitats and prevent further genetic erosion.
MAIN CONCLUSION: This study identified the historical geoclimatic factors which caused low genetic diversity and strong phylogeographic structure in a cryptoviviparous mangrove. The phylogeographic pattern was used to suggest conservation actions. Phylogeographic studies are used to understand the spatial distribution and evolution of genetic diversity, and have major conservation implications, especially for threatened taxa like the mangroves. This study aimed to assess the phylogeographic pattern of Aegiceras corniculatum, a cryptoviviparous mangrove, across its distribution range in the Indo-West Pacific (IWP) region. We genotyped 398 samples, collected from 37 populations, at four chloroplast DNA (cpDNA) loci, and identified the influence of historical processes on the contemporary population structure of the species. Low genetic diversity at the population level was observed. The evolutionary relationship between 12 cpDNA haplotypes suggested a strong phylogeographic structure, which was further validated by the clustering algorithms and proportioning of maximum variation among hierarchical population groups. The magnitude and direction of historical gene flow indicated that the species attained its wide distribution from its likely ancestral area of the Malay Archipelago. The divergence time estimates of the haplotypes indicated that the geoclimatic changes during the Pleistocene, especially the glacial sea-level changes and emergence of landmasses, hindered genetic exchange and created genetic differentiation between the phylogenetic groups. The species overwintered the last glacial maxima in multiple refugia in the IWP, as identified by the environmental niche modelling. Overall, our findings indicated that ancient glacial vicariance had influenced the present genetic composition of A. corniculatum, which was maintained by the current demographic features of this region. We discussed how these findings can be used to prioritize areas for conservation actions, restore disturbed habitats and prevent further genetic erosion.
Authors: Corey Devin Anderson; Bryan K Epperson; Marie-Josée Fortin; Rolf Holderegger; Patrick M A James; Michael S Rosenberg; Kim T Scribner; Stephen Spear Journal: Mol Ecol Date: 2010-08-13 Impact factor: 6.185
Authors: N C Duke; J-O Meynecke; S Dittmann; A M Ellison; K Anger; U Berger; S Cannicci; K Diele; K C Ewel; C D Field; N Koedam; S Y Lee; C Marchand; I Nordhaus; F Dahdouh-Guebas Journal: Science Date: 2007-07-06 Impact factor: 47.728