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Mechanisms of Evolution

Beyond Darwin and Neo-Darwinism


Nature Reviews Microbiology - Reviews: "Horizontal genomics is a new field in prokaryotic biology that is focused on the analysis of DNA sequences in prokaryotic chromosomes that seem to have originated from other prokaryotes or eukaryotes. However, it is equally important to understand the agents that effect DNA movement: plasmids, bacteriophages and transposons. Although these agents occur in all prokaryotes, comprehensive genomics of the prokaryotic mobile gene pool or 'mobilome' lags behind other genomics initiatives owing to challenges that are distinct from cellular chromosomal analysis. Recent work shows promise of improved mobile genetic element (MGE) genomics and consequent opportunities to take advantage � and avoid the dangers � of these 'natural genetic engineers'. This review describes MGEs, their properties that are important in horizontal gene transfer, and current opportunities to advance MGE genomics.

Although MGEs are the main agents of horizontal gene transfer (HGT), relatively few have been sequenced and analysis of their genomic and phylogenetic properties lags behind that of organismal chromosomes. Specifically, the major databases do not curate plasmid and phage nucleic acid or protein sequences. Sequencing MGE genomes presents unique challenges because phages require suitable hosts for propagation and plasmids must be physically separated from each other and from the host chromosomal DNA. The relatively small size of MGEs (5−500 kb) and their varied GC content thwart current automated annotation algorithms."

Laura S. Frost, Raphael Leplae, Anne O. Summers & Ariane Toussaint MOBILE GENETIC ELEMENTS: THE AGENTS OF OPEN SOURCE EVOLUTION Nature Reviews Microbiology 3, 722-732 (2005); doi:10.1038/nrmicro1235

External : Transposons part 1, transposons part 2 : Barbara McClintock and mobile genetic elements :

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. . . evolving since 10/06/06