Linked Life Data

17211548

Source:http://linkedlifedata.com/resource/pubmed/id/17211548

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2007-1-22
pubmed:abstractText
The fate of gene duplicates subjected to diversifying selection was tested experimentally in a bacterial system. The wild-type TEM-1 beta-lactamase gene confers resistance to ampicillin but not to cefotaxime. Point mutations confer cefotaxime resistance, but they compromise ampicillin resistance. Thus, selection for both drug resistances in a bacterium with two copies of beta-lactamase should favor the divergence of one copy to improve cefotaxime resistance while maintaining the other copy to preserve ampicillin resistance. This selection was performed on a bacterium with identical sequences of beta-lactamase on two separate, compatible plasmids. As expected, one plasmid evolved increased cefotaxime resistance when appropriately strong cefotaxime selection was applied. However, the cefotaxime-resistant plasmid maintained sufficient ampicillin resistance to tolerate the concentration of ampicillin used, and the other plasmid was lost. Hosts carrying both the cefotaxime-resistant and wild-type plasmids were then subjected to various higher concentrations of both drugs to find conditions that would ensure the maintenance of both plasmids. In a striking contradiction to our model, no such conditions were found. The fitness cost of carrying both plasmids increased dramatically as antibiotic levels were raised, and either the wild-type plasmid was lost or the cells did not grow. This study highlights the importance of the cost of duplicate genes and the quantitative nature of the tradeoff in the evolution of gene duplication through functional divergence.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0022-2844
pubmed:author
pubmed:issnType
Print
pubmed:volume
64
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
215-22
pubmed:dateRevised
2007-12-3
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Experimental evolution of gene duplicates in a bacterial plasmid model.
pubmed:affiliation
Section of Evolution and Ecology, Center for Population Biology, University of California, Davis, CA 95616, USA. akholloway@ucdavis.edu
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural