Characterisation of adaptive genetic diversity in environmentally contrasted populations of Eucalyptus camaldulensis Dehnh. (river red gum).

As an increasing number of ecosystems face departures from long standing environmental conditions under climate change, our understanding of the capacity of species to adapt will become important for directing conservation and management of biodiversity. Insights into the potential for genetic adaptation might be gained by assessing genomic signatures of adaptation to historic or prevailing environmental conditions. The river red gum (Eucalyptus camaldulensis Dehnh.

Class 1 integrons in benthic bacterial communities: abundance, association with Tn402-like transposition modules and evidence for coselection with heavy-metal resistance.

The integron/gene cassette system contributes to lateral gene transfer of genetic information in bacterial communities, with gene cassette-encoded proteins potentially playing an important role in adaptation to stress. Class 1 integrons are a particularly important class as they themselves seem to be broadly disseminated among the Proteobacteria and have an established role in the spread of antibiotic resistance genes. The abundance and structure of class 1 integrons in freshwater sediment bacterial communities was assessed through sampling of 30 spatially distinct sites encompassing different substrate and catchment types from the Greater Melbourne Area of Victoria, Australia.

Effect of altitude on the genetic structure of an Alpine grass, Poa hiemata.

Background And Aims: The persistence of plants inhabiting restricted alpine areas under climate change will depend upon many factors including levels of genetic variation in adaptive traits, population structure, and breeding system.

Methods: Using microsatellite markers, the genetic structure of populations of a relatively common alpine grass, Poa hiemata, is examined across three altitudinal gradients within the restricted Australian alpine zone where this species has previously been shown to exhibit local adaptation across a narrow altitudinal gradient.

Key Results: Genetic variation across six microsatellite markers revealed genetic structuring along altitudinal transects, and a reduction in genetic variation at high and low altitude extremes relative to sites central within transects.

Divergence of mate recognition behavior and its consequences for genetic architectures of speciation.

The divergence of premating behavior and morphology plays a primary role in speciation, and an understanding of the genetic architectures of these phenotypes is essential for the evaluation of models of the speciation process. However, our empirical knowledge of the genetics underlying speciation-related traits remains limited. In this article, we argue that a dissection of specific aspects of the genetic architecture of such traits in a comparative context can allow us to rule out some mechanisms of divergence.

QTL analysis of a rapidly evolving speciation phenotype in the Hawaiian cricket Laupala.

In mate recognition systems, the functional necessity to coordinate traits involved in sexual communication should result in reduced pairing potential for new variants outside the distribution of common reproductive signals. Yet, many closely related, sexual species differ in mate recognition traits, suggesting that directional selection influences the divergence of mate recognition systems. Species of the endemic Hawaiian cricket genus Laupala are morphologically and ecologically cryptic, although both male calling song and female acoustic preference have diverged rapidly between closely related species.