Chernobyl Birds Have Smaller Brains
Anders Pape Møller1*, Andea Bonisoli-Alquati2, Geir Rudolfsen3, Timothy A. Mousseau2
1 Laboratoire d'Ecologie, Systématique et Evolution, CNRS UMR 8079, Université Paris-Sud, Orsay, France, 2 Norwegian Radiation Protection Authority (NRPA), Department of Environmental Radioactivity, The Polar Environmental Center, Tromsø, Norway, 3 Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, United States of America
Abstract
Background
Animals living in areas contaminated by radioactive material from Chernobyl suffer from increased oxidative stress and low levels of antioxidants. Therefore, normal development of the nervous system is jeopardized as reflected by high frequencies of developmental errors, reduced brain size and impaired cognitive abilities in humans. Alternatively, associations between psychological effects and radiation have been attributed to post-traumatic stress in humans.
Methodology/Principal Finding
Here we used an extensive sample of 550 birds belonging to 48 species to test the prediction that even in the absence of post-traumatic stress, there is a negative association between relative brain size and level of background radiation. We found a negative association between brain size as reflected by external head volume and level of background radiation, independent of structural body size and body mass. The observed reduction in brain size in relation to background radiation amounted to 5% across the range of almost a factor 5,000 in radiation level. Species differed significantly in reduction in brain size with increasing background radiation, and brain size was the only morphological character that showed a negative relationship with radiation. Brain size was significantly smaller in yearlings than in older individuals.
Conclusions/Significance
Low dose radiation can have significant effects on normal brain development as reflected by brain size and therefore potentially cognitive ability. The fact that brain size was smaller in yearlings than in older individuals implies that there was significant directional selection on brain size with individuals with larger brains experiencing a viability advantage.
Citation: Møller AP, Bonisoli-Alquati A, Rudolfsen G, Mousseau TA (2011) Chernobyl Birds Have Smaller Brains. PLoS ONE 6(2): e16862. doi:10.1371/journal.pone.0016862
Editor: Björn Brembs, Freie Universitaet Berlin, Germany
Received: September 3, 2010; Accepted: January 12, 2011; Published: February 4, 2011
Copyright: © 2011 Møller 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: The authors received funding from the University of South Carolina School of the Environment, Bill Murray and the Samuel Freeman Charitable Trust, the National Science Foundation, NATO, the Fulbright Program, CRDF and the National Geographic Society to conduct their research. The funding agencies 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: anders.moller@u-psud.fr
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NOTA DESTE BLOGGER:
O que fazer dessa pesquisa em termos evolucionários? Pela Síntese Evolutiva Moderna, a mudança provocada pela mutações é que é a sementeira de ganhos evolutivos na história evolucionária de uma espécie. Aqui, o que temos é apenas um caso de adaptação sem várias ave, mas com perdas em termos de aptidão dos indivíduos, e isso em apenas 25 anos.
Quais serão as implicações de tudo isso a longo prazo? Extinção em massa??? Mas as mutações não são responsáveis pela criatividade na produção de complexidade e diversidade das formas biológicas? Aqui, as mutações estão dizimando as populações.
