Relationships within Eucalyptus using chloroplast DNA

Abstract

The potential use of restriction fragment length polymorphisms (RFLPs) of chloroplast DNA to determine relationships at higher taxonomic levels in the genus Eucalptus was examined. Chloroplast DNA from 24 species, encompassing representatives of all the subgenera of Eucalyptus as well as one representative of the genus Angophora, was analysed using four 6-base restriction endonucleases. Eighty-four polymorphisms were obtained (twenty-eight autopomorphic) and the data matrix analysed using both cladistic and phenetic approaches. Results provided relatively good congruence with taxonomic perceptions based on morphological traits. Eucalyptus subgenera Blakella and Corymbia appear to be genetically similar to each other and to Angophora, although their phylogenetic relationships are not resolved in this study. Using Angophora alone, or together with the bloodwoods Blakella and Corynthia, as the outgroup for cladistic analysis, the two representatives of Eudesmia examined form a distinctly separate monophyletic group, which appears to be the sister taxon to Idiogenes, Gaubaen, Monocalyptus and Symphyomyrtus. The results provide some support for the close association of Idiogenes, Gauhaea and Monocalyptus and the hypothesis that they are the sister group of Symphyomyrtus. Taxonomically problematic species Eucalyptus guilfoylei, E. microcorys and E. deglupta were included in the study and it was found that E. guilfoylei appeared to diverge prior to the rest of the Symphyomyrtus, E. microcorys near the root of this clade, while the Telocalyptus representative E. deglupta fell within Symplgvontyrtus. The results obtained from the chloroplast DNA data provided independent support for previous morphological studies while generating new hypotheses and highlighting areas requiring closer examination.

Progress in Myrtaceae genetics and genomics: Eucalyptus as the pivotal genus

“…Most of these bloodwoods have operculate flowers, and resolution of this issue partly lay in the affinities of Corymbia to the genus Angophora that has flowers with free petals and sepals (Ladiges 1997). The marked divergence of the Corymbia lineage from Eucalyptus s. s. and its closer affinities to Angophora were demonstrated in numerous molecular studies (Sale et al 1993;Steane et al 1999Steane et al , 2002Udovicic et al 1995). However, in the large molecular phylogenetic analysis of the eucalypt lineage involving ITS sequences from 90 species, Angophora was nested within the Corymbia clade .…”

Phylogenomics of the green ash eucalypts (Myrtaceae): a tale of reticulate evolution and misidentification

“…In addition, closely related co-occurring taxa in subgenus Eucalyptus (sections Aromatica, Capillulus, Cineraceae and Longitudinales) were sampled (often from more than one individual per species from different locations). Eucalyptus cloeziana (subgenus Idiogenes) was included as an out-group to subgenus Eucalyptus on the basis of previous studies (Sale et al 1993;Hill and Johnson 1995;Ladiges et al 1995;Steane et al 1999;Udovicic and Ladiges 2000;Steane et al 2011 …”

Population genetic analysis and phylogeny reconstruction in Eucalyptus (Myrtaceae) using high-throughput, genome-wide genotyping

“…Because of the expense, a paucity of markers and the large amount of labour involved, only small numbers of samples and markers were used, providing rather coarse resolution of phylogenetic relationships among higher eucalypt taxa (genera and subgenera; Sale et al 1993Sale et al , 1996. As DNA analytical methods progressed and became cheaper, fine-scale restriction site analysis of cpDNA was tested as a means to resolve relationships among closely related species within ser.…”