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Journal of Botany
Volume 2012 (2012), Article ID 510478, 11 pages
http://dx.doi.org/10.1155/2012/510478
Research Article

The Evolutionary Dynamics of Apomixis in Ferns: A Case Study from Polystichoid Ferns

1Key Laboratory of Southern Subtropical Plant Diversity, Fairylake Botanical Garden, Shenzhen & Chinese Academy of Sciences, Shenzhen 518004, China
2Department of Life Sciences, Natural History Museum, London SW7 5BD, UK
3Research Group in Biodiversity Genomics and Environmental Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire SL5 7PY, UK
4Department of Biological Sciences, Qiannan Normal College for Nationalities, Duyun 558000, China
5Computer Network Information Center, Chinese Academy of Sciences, Beijing 100190, China
6State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China

Received 19 July 2012; Revised 20 September 2012; Accepted 20 September 2012

Academic Editor: Karl Joseph Niklas

Copyright © 2012 Hong-Mei Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The disparate distribution of apomixis between the major plant lineages is arguably one of the most paradoxical phenomena in plant evolution. Ferns are particularly interesting for addressing this issue because apomixis is more frequent than in any other group of plants. Here, we use a phylogenetic framework to explore some aspects of the evolution of apomixis in ferns and in particular in the polystichoid ferns. Our findings indicate that apomixis evolved several times independently in three different clades of polystichoid ferns. A lineage-wide perspective across ferns indicates a correlation between apomixis and the species richness of lineages; however BiSSE tests did not recover evidence for a correlation of apomixis and diversification rates. Instead, evidence was recovered supporting an association between the establishment of apomixis and reticulate evolution, especially in the establishment of triploid hybrids. Diversification time estimates supported the hypothesis of short living apomictic lineages and indicated a link between the establishment of apomixis and the strengthening of the monsoons caused by the lifting of the Qinghai-Tibetan plateau. In general our results supported the hypothesis for the rare establishment of apomictic lineages, high extinction risks, and low speciation rates.