Does Sex Speed Up Evolutionary Rate and Increase Biodiversity?
Carlos J. Melián1,2*, David Alonso3, Stefano Allesina1,4, Richard S. Condit5, Rampal S. Etienne3
1 National Center for Ecological Analysis and Synthesis, University of California, Santa Barbara, California, United States of America, 2 Center for Ecology, Evolution and Biogeochemistry, Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland, 3 Community and Conservation Ecology Group, University of Groningen, Groningen, The Netherlands, 4 Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, United States of America, 5 Center for Tropical Forest Science, Smithsonian Tropical Research Institute, Balboa, Ancon, Republic of Panama
Abstract
Most empirical and theoretical studies have shown that sex increases the rate of evolution, although evidence of sex constraining genomic and epigenetic variation and slowing down evolution also exists. Faster rates with sex have been attributed to new gene combinations, removal of deleterious mutations, and adaptation to heterogeneous environments. Slower rates with sex have been attributed to removal of major genetic rearrangements, the cost of finding a mate, vulnerability to predation, and exposure to sexually transmitted diseases. Whether sex speeds or slows evolution, the connection between reproductive mode, the evolutionary rate, and species diversity remains largely unexplored. Here we present a spatially explicit model of ecological and evolutionary dynamics based on DNA sequence change to study the connection between mutation, speciation, and the resulting biodiversity in sexual and asexual populations. We show that faster speciation can decrease the abundance of newly formed species and thus decrease long-term biodiversity. In this way, sex can reduce diversity relative to asexual populations, because it leads to a higher rate of production of new species, but with lower abundances. Our results show that reproductive mode and the mechanisms underlying it can alter the link between mutation, evolutionary rate, speciation and biodiversity and we suggest that a high rate of evolution may not be required to yield high biodiversity.
Author Summary
The role of sex in driving genetic variation and the speed at which new species emerge has been debated for over a century. There is experimental and theoretical evidence that sex increases genetic variation and the speed at which new species emerge, although evidence that sex reduces variation and slows the formation of new species also exists. Surprisingly, given the link between sex and genetic variation, little work has been done on the impact of sex on biodiversity. In the present theoretical study we show that a faster evolutionary rate can decrease the abundance of newly formed species and thus decrease long-term biodiversity. This leads to the paradoxical result that sexual reproduction can increase genetic variation but reduce species diversity. These results suggest that reducing the rate of appearance of genetic variation and the speed at which new species emerge may increase biodiversity in the long-term. This unexpected link between reproductive mode, the speed of evolution and biodiversity suggests that a high evolutionary rate may not be required to yield a large number of species in natural ecosystems.
Citation: Melián CJ, Alonso D, Allesina S, Condit RS, Etienne RS (2012) Does Sex Speed Up Evolutionary Rate and Increase Biodiversity? PLoS Comput Biol 8(3): e1002414. doi:10.1371/journal.pcbi.1002414
Editor: Jan Engelstädter, ETH Zurich, Switzerland
Received: August 4, 2011; Accepted: January 20, 2012; Published: March 8, 2012
Copyright: © 2012 Melián et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: CJM, SA, and RSC were supported by fellowships from the National Center for Ecological Analysis and Synthesis, a Center funded by NSF (Grant \#DEB-0553768), the University of California, Santa Barbara, and the State of California. CJM also acknowledges the support by Microsoft Research Ltd., Cambridge, United Kingdom. DA and RSE acknowledge the support of the Netherlands Organization for Scientific Research (NWO). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
* E-mail: carlos.melian@eawag.ch
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PERGUNTAS DESTE BLOGGER:
E qual é a origem evolucionária do sexo? Darwin e seus discípulos ainda não ofereceram uma teoria científica que explique a origem do sexo.
Repare no que foi encontrado na pesquisa:
We show that faster speciation can decrease the abundance of newly formed species and thus decrease long-term biodiversity. In this way, sex can reduce diversity relative to asexual populations, because it leads to a higher rate of production of new species, but with lower abundances.
Repare no que foi sugerido na pesquisa:
Our results show that reproductive mode and the mechanisms underlying it can alter the link between mutation, evolutionary rate, speciation and biodiversity and we suggest that a high rate of evolution may not be required to yield high biodiversity.
Repare no que foi encontrado na pesquisa:
We show that faster speciation can decrease the abundance of newly formed species and thus decrease long-term biodiversity. In this way, sex can reduce diversity relative to asexual populations, because it leads to a higher rate of production of new species, but with lower abundances.
Repare no que foi sugerido na pesquisa:
Our results show that reproductive mode and the mechanisms underlying it can alter the link between mutation, evolutionary rate, speciation and biodiversity and we suggest that a high rate of evolution may not be required to yield high biodiversity.
Traduzindo em miúdos: Se não for X, então Y; se não for Y, então Z; se não for Z, então todo o ABC!!!
Não é de se estranhar que a teoria da evolução de Darwin através da seleção natural e n mecanismos evolucionárias seja a teoria científica mais corroborada assim como a lei da gravidade e a Terra girar em torno do Sol: qualquer evidência conta a favor de Darwin. Haja elasticidade heurística. Aprendi na universidade que uma teoria que explica tudo não explica nada!
Fui, nem sei por que, rindo da cara de Darwin!!! O homem que teve a maior ideia que toda a humanidade já teve... Há controvérsias desde 1859 de que seja assim uma Brastemp no contexto de justificação teórica!!!
