Genetic discontinuities in a dominant mangrove Rhizophora apiculata (Rhizophoraceae) in the Indo-Malesian region

Guo, Zixiao, Huang, Yelin, Chen, Yongmei, Duke, Norman C., Zhong, Cairong, and Shi, Sugua (2016) Genetic discontinuities in a dominant mangrove Rhizophora apiculata (Rhizophoraceae) in the Indo-Malesian region. Journal of Biogeography, 43. pp. 1856-1868.

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Abstract

Aim: Population genomics data were used to determine the genetic diversity, genetic divergence and genetic structure of the mangrove, Rhizophora apiculata, across its distributional range and to re-assess the evolutionary processes that shaped its current distribution.

Location: The Indo-Malesian region section of the Indo-West Pacific region.

Methods: Next-generation sequencing technology was used to sequence 81 nuclear loci from a pooled DNA sample of 31–44 individuals of Rhizophora apiculata from 11 populations. Five nuclear loci from six to eight individuals from 18 populations were sequenced using conventional Sanger sequencing technology to validate the results.

Results: Genetic diversity at the population level was low (π and θ were < 1.0 × 10−3 in most of the populations), but relatively high at the species level (π = 2.419 × 10−3 and θ = 1.362 × 10−3). The populations of R. apiculata in the Indo-Malesian region were genetically differentiated and grouped into three clusters: east Indian Ocean (EIO), South China Sea (SCS) and Australasia (AUA). Based on the genetic distance matrices, two genetic discontinuities were observed, and they correspond to the Malay Peninsula land barrier and the Wallacea zone. The admixture observed in populations from the Malacca Strait was attributed to asymmetric gene flow through the strait, which was simulated by the isolation-with-migration (IM) model.

Main conclusion: Both the Sunda shelf barrier and ocean currents in Wallacea contributed to the observed genetic discontinuity, which separated R. apiculata into three clusters (SCS, EIO and AUA). The cycle between extinction and recolonization in the SCS in response to Pleistocene sea level fluctuations reduced the genetic diversity within populations. The repeated opening and closing of the gene flow corridors, such as the Malacca Strait, may have blurred the genetic discontinuities to an extent and introduced an admixture into populations in boundary areas.

Item ID: 44684
Item Type: Article (Research - C1)
ISSN: 1365-2699
Keywords: biogeography, evolution, genetic structure, Indo-Malesian region, land barrier, mangrove, population genomics, Rhizophora apiculata
Funders: National Natural Science Foundation of China (NNSFC), State Key Laboratory of Biocontrol, Chang Hungta Science Foundation, Sun Yat-sen University
Projects and Grants: NNSFC #41130208, 91331202, and 41276107, State Key Laboratory of Biocontrol #13A03 and 12K04
Date Deposited: 25 Jul 2016 23:19
FoR Codes: 06 BIOLOGICAL SCIENCES > 0603 Evolutionary Biology > 060302 Biogeography and Phylogeography @ 40%
06 BIOLOGICAL SCIENCES > 0604 Genetics > 060411 Population, Ecological and Evolutionary Genetics @ 30%
06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 30%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960802 Coastal and Estuarine Flora, Fauna and Biodiversity @ 40%
96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960805 Flora, Fauna and Biodiversity at Regional or Larger Scales @ 30%
96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960503 Ecosystem Assessment and Management of Coastal and Estuarine Environments @ 30%
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