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Zschaler G.,Max Planck Institute For Physik Komplexer Systeme | Traulsen A.,Max Planck Institute For Evolutionsbiologie | Gross T.,Max Planck Institute For Physik Komplexer Systeme
New Journal of Physics

We consider the evolutionary dynamics of a cooperative game on an adaptive network, where the strategies of agents (cooperation or defection) feed back on their local interaction topology. While mutual cooperation is the social optimum, unilateral defection yields a higher payoff and undermines the evolution of cooperation. Although no a priori advantage is given to cooperators, an intrinsic dynamical mechanism can lead asymptotically to a state of full cooperation. In finite systems, this state is characterized by long periods of strong cooperation interrupted by sudden episodes of predominant defection, suggesting a possible mechanism for the systemic failure of cooperation in realworld systems. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. Source

Tautz D.,Max Planck Institute For Evolutionsbiologie | Domazet-Loso T.,University of Kiel | Domazet-Loso T.,Ruder Boskovic Institute
Nature Reviews Genetics

Gene evolution has long been thought to be primarily driven by duplication and rearrangement mechanisms. However, every evolutionary lineage harbours orphan genes that lack homologues in other lineages and whose evolutionary origin is only poorly understood. Orphan genes might arise from duplication and rearrangement processes followed by fast divergence; however, de novo evolution out of non-coding genomic regions is emerging as an important additional mechanism. This process appears to provide raw material continuously for the evolution of new gene functions, which can become relevant for lineage-specific adaptations. © 2011 Macmillan Publishers Limited. All rights reserved. Source

Boell L.,Max Planck Institute For Evolutionsbiologie
Evolution and Development

Evolution along "lines of least resistance (LLR)" is a well-established phenomenon, which is ultimately based on variational properties of the developmental system. However, it has remained unclear which aspects of development are responsible for observed distributions of variation. This article suggests that house mouse mandible shape may present an opportunity for future research in this field. The genetic architecture of mouse mandible shape has been investigated in the laboratory, and its evolution has been surveyed in studies on natural variation. Here, I ask whether evolutionary diversification of mandible shape follows "LLR" by comparing principal directions of genetic and evolutionary variation, and I assess the potential contribution of specific genomic regions to evolutionary divergence along these directions. The role of two aspects of development, QTL number (presumably reflecting mutational target size) and canalization, is comparatively assessed. Overall, our results demonstrate a strong tendency of genetic and evolutionary systems to vary along similar directions, suggesting that mandible shape evolves along LLR at the level of populations, subspecies and species. At the level of genetic factors, effects bearing similarity to directions of evolution are significantly overrepresented, providing support for the mutational target size hypothesis. A role for canalization is not supported by a clear correlation between directions of evolution and size of genetic effects; however, the evidence for canalization remains ambiguous. These results provide some insights into how the developmental system may shape the variational properties of genetic systems and thus influence the direction of evolution. © 2013 Wiley Periodicals, Inc. Source

Sestak M.S.,Ruder Boskovic Institute | Bozicevic V.,Ludwig Maximilians University of Munich | Bakaric R.,Ruder Boskovic Institute | Bakaric R.,Max Planck Institute For Evolutionsbiologie | And 3 more authors.
Frontiers in Zoology

Background: The vertebrate head is a highly derived trait with a heavy concentration of sophisticated sensory organs that allow complex behaviour in this lineage. The head sensory structures arise during vertebrate development from cranial placodes and the neural crest. It is generally thought that derivatives of these ectodermal embryonic tissues played a central role in the evolutionary transition at the onset of vertebrates. Despite the obvious importance of head sensory organs for vertebrate biology, their evolutionary history is still uncertain.Results: To give a fresh perspective on the adaptive history of the vertebrate head sensory organs, we applied genomic phylostratigraphy to large-scale in situ expression data of the developing zebrafish Danio rerio. Contrary to traditional predictions, we found that dominant adaptive signals in the analyzed sensory structures largely precede the evolutionary advent of vertebrates. The leading adaptive signals at the bilaterian-chordate transition suggested that the visual system was the first sensory structure to evolve. The olfactory, vestibuloauditory, and lateral line sensory organs displayed a strong link with the urochordate-vertebrate ancestor. The only structures that qualified as genuine vertebrate innovations were the neural crest derivatives, trigeminal ganglion and adenohypophysis. We also found evidence that the cranial placodes evolved before the neural crest despite their proposed embryological relatedness.Conclusions: Taken together, our findings reveal pre-vertebrate roots and a stepwise adaptive history of the vertebrate sensory systems. This study also underscores that large genomic and expression datasets are rich sources of macroevolutionary information that can be recovered by phylostratigraphic mining. © 2013 Šestak et al.; licensee BioMed Central Ltd. Source

Boell L.,Max Planck Institute For Evolutionsbiologie | Tautz D.,Max Planck Institute For Evolutionsbiologie
BMC Evolutionary Biology

Abstract. Background: Insights into the micro-evolutionary patterns of morphological traits require an assessment of the natural variation of the trait within and between populations and closely related species. The mouse mandible is a particularly suitable morphological trait for such an analysis, since it has long been used as a model to study the quantitative genetics of shape. In addition, many distinct populations, sub-species and closely related species are known for the house mouse. However, morphological comparisons among wild caught animals require an assessment in how far environmental and technical factors could interfere with the shape change measurements. Results: Using geometric morphometrics, we have surveyed mandible shapes in 15 natural populations of the genus Mus, with a focus on the subspecies Mus musculus domesticus. In parallel we have carefully assessed possibly confounding technical and biological factors. We find that there are distinct differences on average between populations, subspecies and species, but these differences are smaller than differences between individuals within populations. Populations from summer-dry regions, although more ancestral, are less distinct from each other than are populations from the more recently colonized northern areas. Populations with especially distinct shapes occur in an area of sympatry of M. m. domesticus and M. spretus and on recently colonized sub-antarctic islands. We have also studied a number of inbred strains to assess in how far their mandible shapes resemble those from the wild. We find that they fall indeed into the shape space of natural variation between individuals in populations. Conclusions: Although mandible shapes in natural populations can be influenced by environmental variables, these influences are insufficient to explain the average extent of shape differences between populations, such that evolutionary processes must be invoked to explain this level of diversity. We discuss that adaptive evolution may contribute to shape changes between populations, in particular in newly colonized areas. A comparison between inbred strains and wild mice suggests that the laboratory environment has no major systematic effect on the mandible shape and that such strains can be used as representatives of the natural shape differences between individuals. © 2011Boell and Tautz; licensee BioMed Central Ltd. Source

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