Quantitative analysis of mutation and selection pressures on base composition skews in bacterial chromosomes.

ABSTRACT:

Background

Most bacterial chromosomes exhibit asymmetry of base composition with respect to leading vs. lagging strands (GC and AT skews). These skews reflect mainly those in protein coding sequences, which are driven by asymmetric mutation pressures during replication and transcription (notably asymmetric cytosine deamination) plus subsequent selection for preferred structures, signals, amino acid or codons. The transcription-associated effects but not the replication-associated effects contribute to the overall skews through the uneven distribution of the coding sequences on the leading and lagging strands.

Results

Analysis of 185 representative bacterial chromosomes showed diverse and characteristic patterns of skews among different clades. The base composition skews in t

SUBMITTER: Chen C 

PROVIDER: S-EPMC2031905 | biostudies-literature | 2007 Aug

REPOSITORIES: biostudies-literature