Genome sequences of three temperate actinobacteriophages from clusters FA and AS.

Three novel temperate siphoviruses, Juno112, KHumphrey, and ChuckDuck, were isolated from soil at Stevenson University using the bacterium B-2979. Based on gene content similarity, Juno112 and KHumphrey are assigned to actinobacteriophage cluster AS3 and ChuckDuck to cluster FA. All three phages encode tyrosine recombinases, with ChuckDuck encoding two.

Scaling the fitness effects of mutations with respect to differentially adapted Arabidopsis thaliana accessions under natural conditions.

Mutations are the ultimate source of genetic variation for natural selection to act upon. A major question in evolutionary biology is the extent to which new mutations can generate genetic variation under natural conditions to permit adaptive evolution over ecological time scales. Here we collected fitness data for chemically induced (ethylmethane sulfonate, EMS) mutant lines descended from two Arabidopsis thaliana ecotypes that show differential adaptation to the local environment of our common garden plot.

Adaptation without Specialization Early in a Host Shift.

AbstractStudents of speciation debate the role of performance trade-offs across different environments early in speciation. We tested for early performance trade-offs with a host shift experiment using a member of the species complex of treehoppers (Hemiptera: Membracidae). In this clade of plant-feeding insects, different species live on different host plants and exhibit strong behavioral and physiological host specialization.

Collateral fitness effects of mutations.

The distribution of fitness effects of mutation plays a central role in constraining protein evolution. The underlying mechanisms by which mutations lead to fitness effects are typically attributed to changes in protein specific activity or abundance. Here, we reveal the importance of a mutation's collateral fitness effects, which we define as effects that do not derive from changes in the protein's ability to perform its physiological function.

The effect of induced mutations on quantitative traits in : Natural versus artificial conditions.

Mutations are the ultimate source of all genetic variations. New mutations are expected to affect quantitative traits differently depending on the extent to which traits contribute to fitness and the environment in which they are tested. The dogma is that the preponderance of mutations affecting fitness will be skewed toward deleterious while their effects on nonfitness traits will be bidirectionally distributed.

Fisher's geometric model predicts the effects of random mutations when tested in the wild.

Fisher's geometric model of adaptation (FGM) has been the conceptual foundation for studies investigating the genetic basis of adaptation since the onset of the neo Darwinian synthesis. FGM describes adaptation as the movement of a genotype toward a fitness optimum due to beneficial mutations. To date, one prediction of FGM, the probability of improvement is related to the distance from the optimum, has only been tested in microorganisms under laboratory conditions.

Evidence for parallel adaptation to climate across the natural range of Arabidopsis thaliana.

How organisms adapt to different climate habitats is a key question in evolutionary ecology and biological conservation. Species distributions are often determined by climate suitability. Consequently, the anthropogenic impact on earth's climate is of key concern to conservation efforts because of our relatively poor understanding of the ability of populations to track and evolve to climate change.

One hundred years of pleiotropy: a retrospective.

Pleiotropy is defined as the phenomenon in which a single locus affects two or more distinct phenotypic traits. The term was formally introduced into the literature by the German geneticist Ludwig Plate in 1910, 100 years ago. Pleiotropy has had an important influence on the fields of physiological and medical genetics as well as on evolutionary biology.