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The Frequency of Polyploid Speciation in Vascular Plants
Troy E. Wood, Naoki Takebayashi, Michael S. Barker, Itay Mayrose, Philip B. Greenspoon, Loren H. Rieseberg and Peter R. Crane
Proceedings of the National Academy of Sciences of the United States of America
Vol. 106, No. 33 (Aug. 18, 2009), pp. 13875-13879
Published by: National Academy of Sciences
Stable URL: http://www.jstor.org/stable/40484335
Page Count: 5
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Since its discovery in 1907, polyploidy has been recognized as an important phenomenon in vascular plants, and several lines of evidence indicate that most if not all, plant species ultimately have a polyploid ancestry. However, previous estimates of the frequency of polyploid speciation suggest that the formation and establishment of neopolyploid species is rare. By combining information from the botanical community's vast cytogenetic and phylogenetic databases, we establish that 15% of angiosperm and 31% of fern speciation events are accompanied by ploidy increase. These frequency estimates are higher by a factor of four than earlier estimates and lead to a standing incidence of polyploid species within genera of 35% (n = 1,506). Despite this high incidence, we find no direct evidence that polyploid lines, once established, enjoy greater net species diversification. Thus, the widespread occurrence of polyploid taxa appears to result from the substantial contribution of polyploidy to cladogenesis, but not from subsequent increases in diversification rates of polyploid lines.
Proceedings of the National Academy of Sciences of the United States of America © 2009 National Academy of Sciences