Some Sort of Species Certain populations of bacteria are known to show ecological differentiation, but how this happens has remained controversial. Shapiro et al. (p. 48; see the Perspective by Papke and Gogarten) examined whole-genome sequences from ecologically divergent Vibrio populations and found that genes and genome regions containing so-called “eco-SNPs” (single-nuleotide polymorphisms) have swept through populations. These regions differentiate the bacteria genetically, apparently according to the type of substratum on which they live. Subsequently, tight genotypic clusters may have emerged as a result of preferential recombination occurring within particular habitats. Although specialization into different habitats may reduce gene flow between bacterial populations, the bacteria will always remain open to taking up DNA from other populations and so they cannot be said to be species in the eukaryotic sense. Ecologically separated Vibrio populations diverge by gene-specific rather than genome-wide selective sweeps. Genetic exchange is common among bacteria, but its effect on population diversity during ecological differentiation remains controversial. A fundamental question is whether advantageous mutations lead to selection of clonal genomes or, as in sexual eukaryotes, sweep through populations on their own. Here, we show that in two recently diverged populations of ocean bacteria, ecological differentiation has occurred akin to a sexual mechanism: A few genome regions have swept through subpopulations in a habitat-specific manner, accompanied by gradual separation of gene pools as evidenced by increased habitat specificity of the most recent recombinations. These findings reconcile previous, seemingly contradictory empirical observations of the genetic structure of bacterial populations and point to a more unified process of differentiation in bacteria and sexual eukaryotes than previously thought.

Population Genomics of Early Events in the Ecological Differentiation of Bacteria

© 2014 Medema et al. Bacterial secondary metabolites are widely used as antibiotics, anticancer drugs, insecticides and food additives. Attempts to engineer their biosynthetic gene clusters (BGCs) to produce unnatural metabolites with improved properties a

A Systematic Computational Analysis of Biosynthetic Gene Cluster Evolution: Lessons for Engineering Biosynthesis - eScholarship

All organisms produce specialized organic molecules, ranging from small volatile chemicals to large gene-encoded peptides, that have evolved to provide them with diverse cellular and ecological functions. As natural products, they are broadly applied in medicine, agriculture and nutrition. The rapid accumulation of genomic information has revealed that the metabolic capacity of virtually all organisms is vastly underappreciated. Pioneered mainly in bacteria and fungi, genome mining technologies are accelerating metabolite discovery. Recent efforts are now being expanded to all life forms, including protists, plants and animals, and new integrative omics technologies are enabling the increasingly effective mining of this molecular diversity.

Mining genomes to illuminate the specialized chemistry of life

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cblaster: a remote search tool for rapid identification and visualization of homologous gene clusters

Genes involved in coordinated biological pathways, including metabolism, drug resistance and virulence, are often collocalised as gene clusters. Identifying homologous gene clusters aids in the study of their function and evolution, however existing tools are limited to searching local sequence databases. Tools for remotely searching public databases are necessary to keep pace with the rapid growth of online genomic data. Here, we present cblaster, a Python based tool to rapidly detect collocated genes in local and remote databases. cblaster is easy to use, offering both a command line and a user-friendly graphical user interface (GUI). It generates outputs that enable intuitive visualisations of large datasets, and can be readily incorporated into larger bioinformatic pipelines. cblaster is a significant update to the comparative genomics toolbox. cblaster source code and documentation is freely available from GitHub under the MIT license (github.com/gamcil/cblaster).

https://biorxiv.org/content/10.1101/2020.11.08.370601v1.full.pdf

César Aguilar-Martínez

Papers

Evolutionary dynamics of natural product biosynthesis in bacteria