Scott L Nuismer

..Taken together, our results show that coevolutionary selection can be an important force within mutualistic communities, driving changes in trait distributions, interaction rates, and even network structure...

..We demonstrate that in the face of recurrent maladaptive gene flow, recessive alleles can fuel adaptation only when their frequency exceeds a critical threshold within the ancestral range...

..Finally, our results demonstrate that there is no a priori reason to expect the traits of interacting species should match in any literal sense, even in the absence of gene flow among populations...

..Together, our results demonstrate parasites can generate significant phenotypic selection, but that such selection may be sporadic across populations and time...

..The result is often repeated, and potentially rapid, evolutionary shifts in patterns of specialization within networks of interacting species...

..Consequently, empirical studies that describe only patterns of local adaptation or maladaptation do not provide evidence either for or against the theory...

..Our results also generate novel predictions for the expected sign and magnitude of linkage disequilibria in each species...

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..Our model provides testable predictions that can help interpret accumulating data on expression levels for genes relevant to host-parasite interactions...

..In all cases, our results reveal the surprising conclusion that both positive and negative genetic correlations between traits have qualitatively identical effects on coevolutionary dynamics...

..These results are consistent with the predominance of haploidy among parasitic protists...

..In some cases, particularly those where mating occurs within groups, we find that assortative mating evolves sufficiently to catalyze sympatric speciation in the interacting species...

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..Hence, as the geographical range of a parasite increases, it becomes increasingly maladapted to the host. This suggests a novel mechanism through which the geographical range of parasites may be limited...

..These results are compared with those from spatial models with unrestricted movement. The comparisons demonstrate that gene flow is unnecessary for generating empirical patterns predicted by the geographic mosaic theory of coevolution...

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..As a consequence, reciprocal adaptation between host and parasite can become uncoupled from the rate of host gene flow...

..Our results thus narrow the scope over which the predictions of the geographic mosaic theory are likely to hold and provide novel and readily testable predictions about when and where local maladaptation is expected...

..These results help to explain recent empirical findings that suggest that many contemporary polyploid lineages arose during the Cretaceous-Tertiary extinction, without invoking adaptive advantages of polyploidy...

..We show that this effect can substantially impede sympatric speciation. Our results emphasize the need for data on the strength of the stabilizing component of selection generated by mating in natural populations...

..In contrast, our results do not provide evidence that polyploidization results in immediate and substantial shifts in the genetic covariance matrix...

..This effect can be quite strong and, in the case of perennial species with recurrent polyploid formation, may last indefinitely, potentially providing a general explanation for the successful establishment of novel polyploid lineages...

..Together with the results of recent phylogenetic and ecological studies, these results suggest that the causes of diversification in many coevolutionary systems may require reassessment...

..Thus, identifying the genetic architecture of infection and resistance in real systems is of central importance...

..Our results show that species interactions typically select against sex. We conclude that, although the Red Queen favors sex under certain circumstances, it alone does not account for the ubiquity of sex...

..Taken as a whole, these theoretical results suggest that many features of mutualistic coevolution can best be understood by considering spatial, temporal, and community-dependent patterns of fitness interactions...

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