Frequency-dependent selection maintains clonal diversity in an asexual organism
- Centre for Environmental Stress and Adaptation Research, Department of Genetics, University of Melbourne, Parkville, Victoria 3010, Australia
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Edited by May R. Berenbaum, University of Illinois, Urbana, IL, and approved September 25, 2008. (received for review June 26, 2008)
Abstract
Asexual organisms can be genetically variable and evolve through time, yet it is not known how genetic diversity is maintained in populations. In sexual organisms, negative frequency-dependent selection plays a role in maintaining diversity at some loci, but in asexual organisms, this mechanism could provide a general explanation for persistent genetic diversity because it acts on the whole genome and not just on some polymorphisms within a genome. Using field manipulations, we show that negative frequency-dependent selection maintains clonal diversity in an asexual mite species, and we link predicted equilibrium clonal frequencies to average frequencies in space and time. Intense frequency-dependent selection is likely to be a general mechanism for persistent genetic diversity in asexual organisms.
Footnotes
- 1To whom correspondence should be addressed. E-mail: aweeks{at}unimelb.edu.au
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Author contributions: A.R.W. and A.A.H. designed research; A.R.W. performed research; A.R.W. analyzed data; and A.R.W. and A.A.H. wrote the paper.
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The authors declare no conflict of interest.
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This article is a PNAS Direct Submission.
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This article contains supporting information online at www.pnas.org/cgi/content/full/0806039105/DCSupplemental.
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Freely available online through the PNAS open access option.
- © 2008 by The National Academy of Sciences of the USA
