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Genetic differentiation in spite of high gene flow in the dominant rainforest tree of southeastern Australia, Nothofagus cunninghamii


Duncan, CJ and Worth, JRP and Jordan, GJ and Jones, RC and Vaillancourt, RE, Genetic differentiation in spite of high gene flow in the dominant rainforest tree of southeastern Australia, Nothofagus cunninghamii, Heredity, 116, (1) pp. 99-106. ISSN 0018-067X (2016) [Refereed Article]

Copyright Statement

Copyright 2015 Macmillan Publishers

DOI: doi:10.1038/hdy.2015.77


Nothofagus cunninghamii is a long-lived, wind-pollinated tree species that dominates the cool temperate rainforests of southeastern Australia. The species' distribution is more or less continuous in western Tasmania but is fragmented elsewhere. However, it is unknown whether this fragmentation has affected the species' genetic architecture. Thus, we examined N. cunninghamii using 12 nuclear microsatellites and 633 individuals from 18 populations spanning the species' natural range. Typical of wind-pollinated trees, there was low range-wide genetic structure (FST = 0.04) consistent with significant gene flow across most of the species' range. However, gene flow was not high enough to overcome the effects of drift across some disjunctions. Victorian populations (separated from Tasmania by the 240 km wide Bass Strait) formed a genetic group distinct from Tasmanian populations, had lower diversity (mean allelic richness (Ar) = 5.4 in Victoria versus 6.9 in Tasmania) and were significantly more differentiated from one another than those in Tasmania (FST = 0.045 in Victoria versus 0.012 in Tasmania). Evidence for bottlenecking was found in small populations that were at least 20 km from other populations. Interestingly, we found little divergence in microsatellite markers between the extremes of genetically based morphological and physiological altitudinal clines suggesting adaptive differentiation is strongly driven by selection because it is likely to be occurring in the presence of gene flow. Even though the cool temperate rainforests of Australia are highly relictual, the species is relatively robust to population fragmentation due to high levels of genetic diversity and gene flow, especially in Tasmania.

Item Details

Item Type:Refereed Article
Keywords:Nothofagus, microsatellites, Lophozonia, dispersal, conservation biology
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Terrestrial ecology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the environmental sciences
UTAS Author:Duncan, CJ (Ms Corrine Duncan)
UTAS Author:Worth, JRP (Dr James Worth)
UTAS Author:Jordan, GJ (Professor Greg Jordan)
UTAS Author:Jones, RC (Dr Rebecca Jones)
UTAS Author:Vaillancourt, RE (Professor Rene Vaillancourt)
ID Code:103843
Year Published:2016
Funding Support:Australian Research Council (DP120100501)
Web of Science® Times Cited:13
Deposited By:Plant Science
Deposited On:2015-10-27
Last Modified:2018-02-02

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