All submissions of the EM system will be redirected to Online Manuscript Submission System. Authors are requested to submit articles directly to Online Manuscript Submission System of respective journal.

Selectional versus mutational mechanism underlying genomic features of bacterial strand asymmetry: a case study in Clostridium acetobutylicum

Author(s): H.-L. Zhao, Z.-K. Xia, Z.-G. Hua and W. Wei

Strand biases are widespread in bacterial genomes. In this review, we discuss 5 types of bias, including gene orientation, the number of open reading frames, nucleotide composition, substitution rate, and gene length, between leading and lagging strands during replication. For each type of strand bias, related studies were summarized and Clostridium acetobutylicum ATCC 824 was used as a representative example to illustrate bias. Our results in C. acetobutylicum indicate that there is little asymmetry between 2 replication strands on open reading frame number and gene length, whereas the other 3 features presented significant strand bias. The underlying mechanisms of mutation and/or selection are discussed. It is hoped that this review will improve the understanding of the extent and reasons for various types of strand bias in bacterial genomes.