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Population subdivision promoted by a sea-level-change-driven bottleneck: a glimpse from the evolutionary history of the mangrove tree Aegiceras corniculatum
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  • Rufan Zhang,
  • Zixiao Guo,
  • Lu Fang,
  • Cairong Zhong,
  • Norman Duke,
  • SUHUA SHI
Rufan Zhang
Sun Yat-Sen University
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Zixiao Guo
Sun Yat-Sen University
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Lu Fang
South China Normal University
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Cairong Zhong
Hainan Academy of Forests
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Norman Duke
James Cook University
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SUHUA SHI
Sun Yat-sen University
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Abstract

Historic climate changes had always driven geographical populations of coastal plants to contract and recover dynamically, even die out completely. Species suffering from such bottlenecks usually lose intraspecific genetic diversity, but how do these events influence population subdivision patterns of coastal plants? We investigated this question in the typical coastal plant: mangrove species Aegiceras corniculatum. Inhabiting the intertidal zone of the tropical and subtropical coast of the Indo-West Pacific oceans, its populations are deemed to be greatly shaped by historic sea-level fluctuations. Using dual methods of Sanger and Illumina Solexa sequencing, we found that the 18 sampled populations were structured into two groups, namely, the “Indo-Malayan” group, comprising three subgroups (the northern South China Sea, Gulf of Bengal, and Bali), and the “Pan-Australasia” group, comprising the subgroups of the southern South China Sea and Australasia. Based on simulations using the approximate Bayesian computation method, we inferred that the southern South China Sea subgroup, which penetrates the interior of the “Indo-Malayan” group, originated from the Australasia subgroup, accompanied by a severe bottleneck event, with a spot of gene flow from both the Australasia and “Indo-Malayan” groups. Geographical barriers such as the Sundaland underlie the genetic break between Indian and Pacific Oceans, but the discontinuity between southern and northern South China Sea was originated from genetic drift in the bottleneck event. Hence, we revealed a case evidencing that the bottleneck event promoted population subdivision. This conclusion may be applicable in other taxa beyond coastal plants.

Peer review status:UNDER REVIEW

08 Jul 2021Submitted to Molecular Ecology
14 Jul 2021Reviewer(s) Assigned
05 Sep 2021Review(s) Completed, Editorial Evaluation Pending