Origins of a morphological cline between Eucalyptus melanophloia and Eucalyptus whitei

Holman, James E., Hughes, Jane M. and Fensham, Roderick J. (2011) Origins of a morphological cline between Eucalyptus melanophloia and Eucalyptus whitei. Australian Journal of Botany, 59 3: 244-252. doi:10.1071/BT10209


Author Holman, James E.
Hughes, Jane M.
Fensham, Roderick J.
Title Origins of a morphological cline between Eucalyptus melanophloia and Eucalyptus whitei
Formatted title
Origins of a morphological cline between Eucalyptus melanophloia and Eucalyptus whitei
Journal name Australian Journal of Botany   Check publisher's open access policy
ISSN 0067-1924
1444-9862
Publication date 2011
Sub-type Article (original research)
DOI 10.1071/BT10209
Volume 59
Issue 3
Start page 244
End page 252
Total pages 9
Place of publication Collingwood, VIC, Australia
Publisher CSIRO Publishing
Collection year 2012
Language eng
Formatted abstract
Most theories to explain the origin and maintenance of clines in Eucalyptus are based on a morphological classification system. The true relationships between putative species along clines require detailed investigation of phylogenetic relationships. A cline between Eucalyptus melanophloia and E. whitei was examined using morphological and molecular analyses to determine whether genetic structuring in nuclear and chloroplast DNA along the cline could be explained by secondary contact between independent evolutionary lineages, or whether the cline represents a single species that has undergone primary differentiation. Morphological analysis showed phenotypic variation distributed continuously across the cline and that seedlings bred true to parental type. Microsatellite analysis indicated that there was little genetic structuring across the cline, and low levels of population differentiation. This result was further reinforced by analysis of the cpDNA. The phylogeographic distribution of cpDNA haplotypes is likely to have resulted from restricted seed-mediated gene flow with isolation by distance. A cogent explanation for the cline is that it has arisen by selection on leaf types promoted by a gradient in precipitation with the short-broad, subsessile leaves of E. melanophloia favoured under higher rainfall and the long, narrow, petiolate leaves of E. whitei favoured in arid environments.
Keyword Natural hybridization
Reticulate evolution
Viminalis Labill
DNA
Complex
Differentiation
Populations
Diversity
Patterns
Globulus
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2012 Collection
School of Biological Sciences Publications
Ecology Centre Publications
 
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Created: Tue, 06 Sep 2011, 11:30:44 EST by Gail Walter on behalf of CRC for Tropical Rainforest Ecology and Management