Origin of African Physacanthus (Acanthaceae) via wide hybridization

PLoS One. 2013;8(1):e55677. doi: 10.1371/journal.pone.0055677. Epub 2013 Jan 30.

Abstract

Gene flow between closely related species is a frequent phenomenon that is known to play important roles in organismal evolution. Less clear, however, is the importance of hybridization between distant relatives. We present molecular and morphological evidence that support origin of the plant genus Physacanthus via "wide hybridization" between members of two distantly related lineages in the large family Acanthaceae. These two lineages are well characterized by very different morphologies yet, remarkably, Physacanthus shares features of both. Chloroplast sequences from six loci indicate that all three species of Physacanthus contain haplotypes from both lineages, suggesting that heteroplasmy likely predated speciation in the genus. Although heteroplasmy is thought to be unstable and thus transient, multiple haplotypes have been maintained through time in Physacanthus. The most likely scenario to explain these data is that Physacanthus originated via an ancient hybridization event that involved phylogenetically distant parents. This wide hybridization has resulted in the establishment of an independently evolving clade of flowering plants.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acanthaceae / classification
  • Acanthaceae / genetics*
  • Evolution, Molecular*
  • Gene Flow
  • Genes, Chloroplast
  • Genetic Variation
  • Hybridization, Genetic*
  • Phenotype
  • Phylogeny
  • Pollen / ultrastructure

Grants and funding

Financial support was provided by a United States National Science Foundation grant to EAT & LAM (DEB-0919594). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.