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Abstract Detail

Systematics Section/ASPT

Jianli, ZHAO [1], Lu, Zhang [1], Dayanandan, Selvadurai [3], Nagaraju, Shivaprakash [3], Qiaoming, Li [1].

Tertiary Origin and Pleistocene Diversification of Dragon Blood Tree (Dracaena cambodiana-Asparagaceae) Populations in the Asian Tropical Forests.

The origin of extraordinarily rich biodiversity in tropical forests is often attributed to evolution under stable climatic conditions over a long period or to climatic fluctuations during the recent Quaternary period. Here we test these two hypotheses using Dracaena cambodiana, a plant species distributed in paleotropical forests. We analyzed nucleotide sequence data of two chloroplast DNA (cpDNA: atpB-rbcL and trnD-trnT) regions and genotype data of six nuclear microsatellites from 15 populations (140 and 363 individuals, respectively) distributed in Indochina Peninsular and Hainan Island to infer the patterns of genetic diversity and phylogeographic structure. The population bottleneck and genetic drift were estimated based upon nuclear microsatellites data using the software programs BOTTLENECK and 2MOD. The lineage divergence times and past population dynamics based on cpDNA data were estimated using coalescent-based isolation-with-migration (IMa) and BEAST software programs. A significant phylogeographic structure (NST = 0.876, GST = 0.796, FST-SSR = 0.329, RST = 0.449; NST > GST, RST > FST-SSR, P < 0.05) and genetic differentiation among populations were detected. Bottleneck analyses and Bayesian skyline plot suggested recent population reduction. The cpDNA haplotype network revealed the ancestral populations from the southern Indochina region expanded to northward. The most recent ancestor divergence time of D. cambodiana dated back to the Tertiary era and rapid diversification of terminal lineages corresponded to the Quaternary period. The results indicated that the present distribution of genetic diversity in D. cambodiana was an outcome of Tertiary dispersal and rapid divergence during the Quaternary period under limited gene flow influenced by the uplift of Himalayan-Tibetan Plateau and Quaternary climatic fluctuations respectively. Evolutionary processes, such as extinction-recolonization during the Pleistocene may have contributed to the fast diversification in D. cambodiana.

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1 - Xishuangbanna Tropical Botanical Garden, the Chinese Academy of Scienc, Plant Phylogenetics and Conservation, Xuefu Road 88, Kunming, Yunnan, 650223, P. R. China
2 - Xishuangbanna Tropical Botanical Garden, the Chinese Academy of Scienc, Plant Phylogenetics and Conservation, Xuefu Road 88, Kunming, Yunnan, 650223, P. R. China
3 - CONCORDIA UNIVERSITY, Department of Biology, 7141 SHERBROOKE STREET WEST, Montréal, QC, H4B 1R5, Canada

Paleotropical biodiversity
Quaternary climate change
fast diversification
uplift of Himalayan-Tibetan Plateau
phylogeographic structure
Dracaena cambodiana.

Presentation Type: Oral Paper:Papers for Sections
Session: 48
Location: Elmwood/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 2:00 PM
Number: 48003
Abstract ID:359
Candidate for Awards:None


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