Repeated, Selection-Driven Genome Reduction of Accessory Genes in Experimental Populations

DSpace/Manakin Repository

Repeated, Selection-Driven Genome Reduction of Accessory Genes in Experimental Populations

Citable link to this page

 

 
Title: Repeated, Selection-Driven Genome Reduction of Accessory Genes in Experimental Populations
Author: Lee, Ming-Chun; Marx, Christopher J

Note: Order does not necessarily reflect citation order of authors.

Citation: Lee, Ming-Chun, and Christopher J. Marx. 2012. Repeated, selection-driven genome reduction of accessory genes in experimental populations. PLoS Genetics 8(5): e1002651.
Full Text & Related Files:
Abstract: Genome reduction has been observed in many bacterial lineages that have adapted to specialized environments. The extreme genome degradation seen for obligate pathogens and symbionts appears to be dominated by genetic drift. In contrast, for free-living organisms with reduced genomes, the dominant force is proposed to be direct selection for smaller, streamlined genomes. Most variation in gene content for these free-living species is of “accessory” genes, which are commonly gained as large chromosomal islands that are adaptive for specialized traits such as pathogenicity. It is generally unclear, however, whether the process of accessory gene loss is largely driven by drift or selection. Here we demonstrate that selection for gene loss, and not a shortened genome, per se, drove massive, rapid reduction of accessory genes. In just 1,500 generations of experimental evolution, 80% of populations of Methylobacterium extorquens AM1 experienced nearly parallel deletions removing up to 10% of the genome from a megaplasmid present in this strain. The absence of these deletion events in a mutation accumulation experiment suggested that selection, rather than drift, has dominated the process. Reconstructing these deletions confirmed that they were beneficial in their selective regimes, but led to decreased performance in alternative environments. These results indicate that selection can be crucial in eliminating unnecessary genes during the early stages of adaptation to a specialized environment.
Published Version: doi:10.1371/journal.pgen.1002651
Other Sources: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3349727/pdf/
Terms of Use: This article is made available under the terms and conditions applicable to Other Posted Material, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAA
Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:10384894
Downloads of this work:

Show full Dublin Core record

This item appears in the following Collection(s)

 
 

Search DASH


Advanced Search
 
 

Submitters