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Data from: Out of Africa to Madagascar - then back? Molecular phylogenetics and biogeography of tribe Tarchonantheae (Asteraceae: Tarchonanthoideae)

Cite this dataset

Kimball, Rebecca T. et al. (2024). Data from: Out of Africa to Madagascar - then back? Molecular phylogenetics and biogeography of tribe Tarchonantheae (Asteraceae: Tarchonanthoideae) [Dataset]. Dryad. https://doi.org/10.5061/dryad.bnzs7h4gc

Abstract

Premise of research. Molecular data have revolutionized inferences of phylogenetic relationships and historical biogeography of flowering plants. Two small genera, Brachylaena and Tarchonanthus, are the only members of Asteraceae tribe Tarchonantheae (subfamily Tarchonanthoideae). The tribe is morphologically distinct within Asteraceae and is resolved as monophyletic with molecular markers. It is distributed in southern Africa and Madagascar. The purposes of the present study were to determine whether molecular data resolve the two genera as monophyletic and to infer the origin and dispersals that produced the current distribution of the tribe.

Methodology. Sequences from the nuclear ribosomal ITS and ETS and plastid rpl16 intron were analyzed using maximum likelihood and Bayesian analyses to resolve phylogenetic relationships within the tribe. An ancestral trait reconstruction assessed the likely ancestral range for Tarchonantheae using BioGeoBEARS, and BEAST was used for dating divergence.

Pivotal results. We resolved Tarchonanthus as a monophyletic group nested within Brachylaena, making the latter genus paraphyletic. All Malagasy species occurred within a strongly supported clade, but also resolved within the clade was the widely distributed African species Brachylaena huillensis. This indicates two dispersal events between Africa and Madagascar—either a single dispersal to Madagascar, followed by back dispersal to Africa, or two independent dispersals from Africa. 

Conclusions. Tarchonanthus is a monophyletic group nested within Brachylaena, rendering the latter genus paraphyletic. An initial dispersal of Brachylaena from Africa to Madagascar with subsequent speciation, followed by back dispersal to Africa, with minimal morphological divergence between the African species and its sister species in Madagascar could explain the current distribution of Brachylaena. Alternatively, there may have been two dispersal events to Madagascar from Africa during the Miocene, but all within the same subclade. Dispersal of flowering plants back to Africa from Madagascar is very rare, if not unprecedented. These dispersal events, and most diversification within the tribe, including the divergence of Tarchonanthus and Brachylaena, took place during the Miocene.

README: Analysis Files associated with https://doi.org/10.5061/dryad.bnzs7h4gc


his Dryad submission includes files associated with https://doi.org/10.5061/dryad.bnzs7h4gc including .fasta alignment files, .xml configuration files for BEAST analyses, raw .tre output files from phylogenetic analyses and BEAST analyses, as well as figures published as part of this article. For any questions, please contact the corresponding author for this dataset or the published manuscript.

Description of the data and file structure

Multiple sequence alignments are saved as .fasta format; these alignments were used in the phylogenetic analyses described in the manuscript text. .xml files are config files used for divergence dating analyses described in the text. .eps files are image/figure files in this article and .tre files are raw .tre output files that resulted from comparative phylogenetic analyses.

.eps files are images that correspond to supplemental figures published in this article and can be opened using Adobe Photoshop. These files can also be accessed through the original published manuscript. 

All sequence data analyzed in this study are available through GenBank under the following GenBank Accession numbers: OQ209888–OQ209936 and OQ291400– OQ291435

Sharing/Access information

Links to other publicly accessible locations of the data:

Data was derived from the following sources: none

Code/Software

n/a

Methods

Sequence data were generated using Sanger sequencing of cleaned PCR products for three loci. Multiple sequence alignment was performed for each locus independently and loci were analyzed individually and as part of a concatenation using Bayesian Inference and Maximum Likelihood. Fossil-calibrated divergence dating analyses were carried out using BEAST and biogeographic reconstruction was performed using BioGeoBEARS. 

Usage notes

Alignment files can be opened using any text editor; tree files can be opened using any phylogenetic tree imaging software (e.g., FigTree), and BEAUTi .xml config files can be opened using a text editor or the BEAUTi v.1.10.4 software. 

Funding

National Science Foundation, Award: BSR-9016349

Global Genome Initiative, Award: GGI-SIBG-2016