113 results match your criteria: "National Evolutionary Synthesis Center[Affiliation]"

Across angiosperms, variable rates of molecular substitution are linked with life-history attributes associated with woody and herbaceous growth forms. As the number of generations per unit time is correlated with molecular substitution rates, it is expected that rates of phenotypic evolution would also be influenced by differences in generation times. Here, we make the first broad-scale comparison of growth-form-dependent rates of niche evolution.

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Climatic variability and unpredictability affect the distribution and abundance of resources and the timing and duration of breeding opportunities. In vertebrates, climatic variability selects for enhanced cognition when organisms compensate for environmental changes through learning and innovation. This hypothesis is supported by larger brain sizes, higher foraging innovation rates, higher reproductive flexibility, and higher sociality in species living in more variable climates.

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Genomic survey data now permit an unprecedented level of sensitivity in the detection of departures from canonical evolutionary models, including expansions in population size and selective sweeps. Here, we examine the effects of seemingly subtle differences among sampling distributions on goodness of fit analyses of site frequency spectra constructed from single nucleotide polymorphisms. Conditioning on the observation of exactly two alleles in a random sample results in a site frequency spectrum that is independent of the scaled rate of neutral substitution (theta).

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Background: Phylogenetic analyses of angiosperm relationships have used only a small percentage of available sequence data, but phylogenetic data matrices often can be augmented with existing data, especially if one allows missing characters. We explore the effects on phylogenetic analyses of adding 378 matK sequences and 240 26S rDNA sequences to the complete 3-gene, 567-taxon angiosperm phylogenetic matrix of Soltis et al.

Results: We performed maximum likelihood bootstrap analyses of the complete, 3-gene 567-taxon data matrix and the incomplete, 5-gene 567-taxon data matrix.

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The long history of reciprocal transplant studies testing the hypothesis of local adaptation has shown that populations are often adapted to their local environments. Yet many studies have not demonstrated local adaptation, suggesting that sometimes native populations are no better adapted than are genotypes from foreign environments. Local adaptation may also lead to trade-offs, in which adaptation to one environment comes at a cost of adaptation to another environment.

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Background: Biology has increasingly recognized the necessity to build and utilize larger phylogenies to address broad evolutionary questions. Large phylogenies have facilitated the discovery of differential rates of molecular evolution between trees and herbs. They have helped us understand the diversification patterns of mammals as well as the patterns of seed evolution.

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Non-homologous end joining (NHEJ) is the major mechanism of double-strand break repair (DSBR) in mammalian cells. NHEJ has traditionally been inferred from experimental systems involving induced double strand breaks (DSBs). Whether or not the spectrum of repair events observed in experimental NHEJ reflects the repair of natural breaks by NHEJ during chromosomal evolution is an unresolved issue.

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Understanding how and why certain clades diversify greatly in morphology whereas others do not remains a major theme in evolutionary biology. Projecting families of phylogenies into multivariate morphospaces can distinguish two scenarios potentially leading to unequal morphological diversification: unequal magnitude of change per phylogenetic branch, and unequal efficiency in morphological innovation. This approach is demonstrated using a case study of skulls in sister clades within the South American fish superfamily Anostomoidea.

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Desiccation tolerance is a complex trait that is broadly but infrequently present throughout the evolutionary tree of life. Desiccation tolerance has played a significant role in land plant evolution, in both the vegetative and reproductive life history stages. In the land plants, the late embryogenesis abundant (LEA) gene families are involved in both abiotic stress tolerance and the development of reproductive propagules.

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Adaptive divergence among populations can result in local adaptation, whereby genotypes in native environments exhibit greater fitness than genotypes in novel environments. A body of theory has developed that predicts how different species traits, such as rates of gene flow and generation times, influence local adaptation in coevolutionary species interactions. We used a meta-analysis of local-adaptation studies across a broad range of host-parasite interactions to evaluate predictions about the effect of species traits on local adaptation.

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geophylobuilder 1.0: an arcgis extension for creating 'geophylogenies'.

Mol Ecol Resour

January 2008

National Evolutionary Synthesis Center, Suite A200, 2024 West Main Street, Durham, NC 27705, USA.

Evolution is inherently a spatiotemporal process; however, despite this, phylogenetic and geographical data and models remain largely isolated from one another. Geographical information systems provide a ready-made spatial modelling, analysis and dissemination environment within which phylogenetic models can be explicitly linked with their associated spatial data and subsequently integrated with other georeferenced data sets describing the biotic and abiotic environment. geophylobuilder 1.

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The role of positive darwinian selection in evolution at the molecular level has been keenly debated for many years, with little resolution. However, a recent increase in DNA sequence data and the development of new methods of analysis have finally made this question tractable. Here, I review the current state-of-play of the field.

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Evolution. Size does not matter for mitochondrial DNA.

Science

April 2006

National Evolutionary Synthesis Center, Durham, NC 27705, USA, and Centre for the Study of Evolution, University of Sussex, Brighton BN1 9QG, UK.

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