Altitudinal gradients, plant hybrid zones and evolutionary novelty

Abbott, R.J.; Brennan, A.C.

Abstract

Altitudinal gradients are characterized by steep changes of the physical and biotic environment that present challenges to plant adaptation throughout large parts of the world. Hybrid zones may form where related species inhabit different neighbouring altitudes and can facilitate interspecific gene flow and potentially the breakdown of species barriers. Studies of such hybrid zones can reveal much about the genetic basis of adaptation to environmental differences stemming from changes in altitude and the maintenance of species divergence in the face of gene flow. Furthermore, owing to recombination and transgressive effects, such hybrid zones can be sources of evolutionary novelty. We document plant hybrid zones associated with altitudinal gradients and emphasize similarities and differences in their structure. We then focus on recent studies of a hybrid zone between two Senecio species that occur at high and low altitude on Mount Etna, Sicily, showing how adaptation to local environments and intrinsic selection against hybrids act to maintain it. Finally, we consider the potential of altitudinal hybrid zones for generating evolutionary novelty through adaptive introgression and hybrid speciation. Examples of homoploid hybrid species of Senecio and Pinus that originated from altitudinal hybrid zones are discussed.

Citation

Abbott, R., & Brennan, A. (2014). Altitudinal gradients, plant hybrid zones and evolutionary novelty. Philosophical Transactions of the Royal Society B: Biological Sciences, 369(1648), Article 20130346. https://doi.org/10.1098/rstb.2013.0346

• Journal Article Type: Article
• Acceptance Date: Dec 30, 2013
• Publication Date: Aug 1, 2014
• Deposit Date: Mar 16, 2015
• Publicly Available Date: Mar 26, 2015
• Journal: Philosophical Transactions of the Royal Society B: Biological Sciences
• Print ISSN: 0962-8436
• Electronic ISSN: 1471-2970
• Publisher: The Royal Society
• Peer Reviewed: Peer Reviewed
• Volume: 369
• Issue: 1648
• Article Number: 20130346
• DOI: https://doi.org/10.1098/rstb.2013.0346
• Keywords: Adaptation, Altitudinal hybrid zones, Hybridization, Introgression, Selection, Speciation.
• Public URL: https://durham-repository.worktribe.com/output/1435337