Short Report

The constancy of gene conservation across divergent bacterial orders

Olin K Silander and Martin Ackermann

Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland 8092

author email corresponding author email

BMC Research Notes 2009, 2:2doi:10.1186/1756-0500-2-2

Published:	7 January 2009

Abstract

Background

Orthologous genes are frequently presumed to perform similar functions. However, outside of model organisms, this is rarely tested. One means of inferring changes in function is if there are changes in the level of gene conservation and selective constraint. Here we compare levels of gene conservation across three bacterial groups to test for changes in gene functionality.

Findings

The level of gene conservation for different orthologous genes is highly correlated across clades, even for highly divergent groups of bacteria. These correlations do not arise from broad differences in gene functionality (e.g. informational genes vs. metabolic genes), but instead seem to result from very specific differences in gene function. Furthermore, these functional differences appear to be maintained over very long periods of time.

Conclusion

These results suggest that even over broad time scales, most bacterial genes are under a nearly constant level of purifying selection, and that bacterial evolution is thus dominated by selective and functional stasis.