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Mutation rates vary significantly within the genome and across species. Recent studies revealed a long suspected replication‐timing effect on mutation rate, but the mechanisms that regulate the increase in mutation rate as the genome is replicated remain unclear. Evidence is emerging, however, that DNA repair systems, in general, are less efficient in late replicating heterochromatic regions compared...
Natural animal populations are rarely screened for ploidy‐level variation at a scale that allows detection of potentially important aberrations of common ploidy patterns. This type of screening can be especially important for the many mixed sexual/asexual systems in which sexuals are presumed to be dioecious diploids and asexuals are assumed to be triploid and all‐female. For example, elevation of...
Logical connections exist between evolutionary modularity and heterochrony, two unifying and structuring themes in the expanding field of evolutionary developmental biology. The former sees complex phenotypes as being made up of semi‐independent units of evolutionary transformation; the latter requires such a modular organization of phenotypes to occur in a localized or mosaic fashion. This conceptual...
Metamorphosis is thought to provide an adaptive decoupling between traits specialized for each life‐history stage in species with complex life cycles. However, an increasing number of studies are finding that larval traits can carry‐over to influence postmetamorphic performance, suggesting that these life‐history stages may not be free to evolve independently of each other. We used a phenotypic selection...
Exploitation by humans affects the size and structure of populations. This has evolutionary and demographic consequences that have typically being studied independent of one another. We here applied a framework recently developed applying quantitative tools from population ecology and selection gradient analysis to quantify the selection on a quantitative trait—birth date—through its association with...
Populations are from time to time exposed to stressful temperatures. Their thermal resistance levels are determined by inherent and plastic mechanisms, which are both likely to be under selection in natural populations. Previous studies on Drosophila species have shown that inherent resistance is highly species specific, and differs among ecotypes (e.g., tropical and widespread species). Apart from...
Adaptation involves the successive substitution of beneficial mutations by selection, a process known as an adaptive walk. Gradualist models of adaptation, which assume that all mutations are small relative to the distance to a fitness optimum, predict that adaptive walks should be longer when the founding genotype is less well adapted. More recent work modeling adaptation as a sequence of moves in...
Bacteria possess a range of mechanisms to move in different environments, and these mechanisms have important direct and correlated impacts on the virulence of opportunistic pathogens. Bacteria use two surface organelles to facilitate motility: a single polar flagellum, and type IV pili, enabling swimming in aqueous habitats and twitching along hard surfaces, respectively. Here, we address whether...
Populations that are connected by immigrants play an important role in evolutionary and conservation biology, yet we have little direct evidence of how such metapopulations change genetically over evolutionary time. We compared historic (1894–1906) to modern (1988–2006) genetic variation in 11 populations of warbler finches at 14 microsatellite loci. Although several lines of evidence suggest that...
Within‐ and between‐host disease processes occur on the same timescales, therefore changes in the within‐host dynamics of parasites, resources, and immunity can interact with changes in the epidemiological dynamics to affect evolutionary outcomes. Consequently, studies of the evolution of disease life histories, that is, infection‐age‐specific patterns of transmission and virulence, have been constrained...
A long‐standing debate in evo–devo research concerns the relative role of protein‐coding and cis‐regulatory regions in adaptation. Recent studies of genetic adaptation have revealed that the number of substitutions contributing to phenotypic variation is lower in cis‐regulatory than in structural regions, which has led to the idea that cis‐regulatory regions are less important in phenotypic adaptation...
The distribution, dynamics, and evolution of insertion sequences (IS), the most frequent class of prokaryotic transposable elements, are conditioned by their ability to horizontally transfer between cells. IS horizontal transfer (HT) requires shuttling by other mobile genetic elements. It is widely assumed in the literature that these vectors are phages and plasmids. By examining the relative abundance...
A life‐history transition to asexuality is typically viewed as leading to a heightened extinction risk, and a number of studies have evaluated this claim by examining the relative ages of asexual versus closely related sexual lineages. Surprisingly, a rigorous assessment of the age of an asexual plant lineage has never been published, although asexuality is extraordinarily common among plants. Here,...
Several species of terrestrial carnivores (Mammalia: Carnivora) have bold contrasting color patterns that, in some species, apparently signal possession of noxious anal gland secretions, or even physical strength and great ferocity; yet the evolutionary drivers of both placement and patterning of these contrasting pelage colors on the body, and the ecological selection pressures underlying them, have...
Phenotypic variation is fundamental to evolutionary change. Variation not only evinces the connectivity of populations but it is also associated with the adaptability and evolvability of taxa. Despite the potential importance of morphological variation in structuring evolutionary patterns, little is known about how relative differences in intraspecific morphological variation and its geographic structure...
The interplay between individual adaptive life histories and populations dynamics is an important issue in ecology. In this context, we considered a seasonal consumer‐resource model with nonoverlapping generations. We focused on the consumers decision‐making process through which they maximize their reproductive output via a differential investment into foraging for resources or reproducing. Our model...
The repeatability of adaptive evolution depends on the ruggedness of the underlying adaptive landscape. We contrasted the relative ruggedness of two adaptive landscapes by measuring the variance in fitness and metabolic phenotype within and among genetically distinct strains of Pseudomonas fluorescens in two environments differing only in the carbon source provided (glucose vs. xylose). Fitness increased...
Although adaptive change is usually associated with complex changes in phenotype, few genetic investigations have been conducted on adaptations that involve sets of high‐dimensional traits. Microarrays have supplied high‐dimensional descriptions of gene expression, and phenotypic change resulting from adaptation often results in large‐scale changes in gene expression. We demonstrate how genetic analysis...
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