Influence of replication on organization and evolution of bacterial genomes

In bacterial chromosomes, strong bias in nucleotide composition has been observed between differently replicated DNA strands (leading and lagging ones), and also in many species between the regions proximal and distal to the origin of replication (on). This bias is also reflected in composition and distribution of genes along the chromosome. Several phenomena connected with the replication of the chromosome are responsible for such polarization, especially mutational pressure, repair mechanisms and recombinations, and also selection pressure. All these phenomena are not indifferent for gene evolution and their rearrangements which are strictly connected with the organization of bacterial chromosome.