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Selfish operons: horizontal transfer may drive the evolution of gene clusters
1Department of Biology, University of Utah, Salt Lake City 84112, USA. lawrence@biology.utah.edu
Genetics
|August 1, 1996
Summary
Gene clusters in bacteria form through DNA transfer, driven by proximity. Clustered genes spread via horizontal transfer, creating mosaic bacterial genomes with novel functions.
Area of Science:
- Microbiology
- Evolutionary Biology
- Genomics
Background:
- Bacterial operons contain genes for single functions.
- Gene loss via drift can occur under weak or absent selection.
- Restoring lost operon functions requires simultaneous gene acquisition.
Purpose of the Study:
- To model the formation of bacterial gene clusters.
- To explain the role of DNA transfer in gene clustering.
- To investigate the evolutionary advantage of gene proximity.
Main Methods:
- Development of a theoretical model for gene cluster formation.
- Analysis of DNA transfer mechanisms (lateral and horizontal).
- Consideration of genetic drift and selection pressures.
Main Results:
- Gene clusters are formed by DNA transfer within and between bacterial taxa.
- Physical proximity of genes increases the probability of successful multiple-gene transfer.
- Clustered genes spread through horizontal transfer, escaping evolutionary loss.
- Gene clustering can be a 'selfish' operon property promoting its own propagation.
Conclusions:
- Horizontal gene transfer and physical proximity drive bacterial gene cluster formation.
- This mechanism contributes to the mosaic structure of bacterial genomes.
- Operon clustering facilitates the acquisition and spread of peripheral metabolic functions.