Pathogenicity islands represent distinct genetic elements encoding virulence factors of pathogenic bacteria. Pathogenicity islands belong to the class of genomic islands, which are common genetic elements sharing a set of unifying features. Genomic islands have been acquired by horizontal gene transfer. In recent years many different genomic islands have been discovered in a variety of pathogen...

Genomic Islands are parts of a genome that has evidence of horizontal origins. The present work is a continuation of our earlier work that identified 25 regions downstream of the small RNAs as hotspots of genomic island integration by analyzing three strains of E.coli and one strain of Shigella spp genomes. Till that work, genomic islands have been identified only at tRNA/tmRNA genes in the ent...

Populations of the malaria mosquito, Anopheles gambiae, are comprised of at least two reproductively isolated, sympatric populations. In this issue, White et al. (2010) use extensive sampling, high-density tiling microarrays, and an updated reference genome to clarify and expand our knowledge of genomic differentiation between these populations. It is now clear that DNA near the centromeres of ...

The field of speciation has seen much renewed interest in the past few years, with theoretical and empirical advances that have moved it from a descriptive field to a predictive and testable one. The goal of this review is to provide a general background on research on speciation as it pertains to fishes. Three major components to the question are first discussed: the spatial, ecological and se...

Salmonella genomic island 1 (SGI1) and variants (SGI1-I and the new variant SGI1-O) were mapped in five strains of Proteus mirabilis isolated from humans and food in China. Sequencing showed that SGI1 and variants were integrated at the 3' end of the chromosomal thdF gene as previously described for Salmonella strains.

The genome of Aeromonas salmonicida subsp. pectinolytica strain 34mel(T), isolated from a heavily polluted river, contains several genomic islands and putative virulence genes. The identification of genes involved in resistance to different kinds of stress sheds light on the mechanisms used by this strain to thrive in an extreme environment.

We adopted the method of Zhang and Zhang (the Z-Island method) to identify genomic islands in seven human pathogens, analyzing their chromosomal DNA sequences. The Z-Island method is a theoretical method for predicting genomic islands in bacterial genomes; it consists of determination of the cumulative GC profile and computation of codon usage bias. Thirty-one genomic islands were found in...

MOTIVATION Some genomic islands contain horizontally transferred genes, which play critical roles in altering the genotypes and phenotypes of organisms, and horizontal gene transfer has been recognized as a universal event throughout bacterial evolution. A windowless method to display the distribution of genomic GC content, the cumulative GC profile, is proposed to identify genomic islands in g...

The compositions of bacterial genomes can be changed rapidly and dramatically through a variety of processes including horizontal gene transfer. This form of change is key to bacterial evolution, as it leads to ‘evolution in quantum leaps’. Horizontal gene transfer entails the incorporation of genetic elements transferred from another organism—perhaps in an earlier generation—directly into the ...

Acquisition of genomic islands plays a central part in bacterial evolution as a mechanism of diversification and adaptation. Genomic islands are non-self-mobilizing integrative and excisive elements that encode diverse functional characteristics but all contain a recombination module comprised of an integrase, associated attachment sites and, in some cases, a recombination directionality factor...