Diversification history and hybridisation of Dacrydium (Podocarpaceae) in remote Oceania

Keppel, Gunnar, Prentis, Peter, Biffin, Ed, Hodgskiss, Paul, Tuisese, Susana, Tuiwawa, Marika V. and Lowe, Andrew J. (2011) Diversification history and hybridisation of Dacrydium (Podocarpaceae) in remote Oceania. Australian Journal of Botany, 59 3: 262-273. doi:10.1071/BT10181

Author Keppel, Gunnar
Prentis, Peter
Biffin, Ed
Hodgskiss, Paul
Tuisese, Susana
Tuiwawa, Marika V.
Lowe, Andrew J.
Title Diversification history and hybridisation of Dacrydium (Podocarpaceae) in remote Oceania
Formatted title
Diversification history and hybridisation of Dacrydium (Podocarpaceae) in remote Oceania
Journal name Australian Journal of Botany   Check publisher's open access policy
ISSN 0067-1924
Publication date 2011-01-01
Sub-type Article (original research)
DOI 10.1071/BT10181
Volume 59
Issue 3
Start page 262
End page 273
Total pages 12
Place of publication Collingwood, VIC, Australia
Publisher CSIRO Publishing
Language eng
Formatted abstract
We examined evolutionary relationships, hybridisation and genetic diversity in species of Dacrydium (Podocarpaceae) in Remote Oceania, where it is restricted to New Caledonia and Fiji. We used cpDNA sequence (trnL–trnF) data to construct a phylogeny and estimate taxon divergence by using a relaxed molecular clock approach. The phylogeny was verified using allozymes, which were also used to investigate genetic diversity of all species and the hybridisation dynamics of two endangered species, D. guillauminii and D. nidulum. Our results suggested that Dacrydium species in Remote Oceania form a monophyletic group that arose and diversified within the last 20 million years through long-distance dispersal and a range of speciation mechanisms. Whereas we detected no hybridisation between the Fijian species D. nausoriense and D. nidulum, we confirmed hybridisation between D. guillauminii and D. araucarioides in New Caledonia and determined introgression to be assymetric from the widespread D. araucarioides into the rare, restricted-range species D. guillauminii. In addition, D. guillauminii had lower genetic diversity than did the other species of Dacrydium studied, which had genetic diversity similar to that of other gymnosperms. Our results provided evidence for the recent and complex diversification of Dacrydium in Remote Oceania. In addition, low genetic diversity of and introgression from D. araucarioides, are of grave concern for the conservation of D. guillauminii.
Keyword Sympatric speciation
Genetic diversity
Manuherikia group
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

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Created: Tue, 06 Sep 2011, 21:32:24 EST by Gail Walter on behalf of CRC for Tropical Rainforest Ecology and Management