DNA replication in prokaryotes
Among prokaryotes, DNA replication in vitro has been studied in great detail in E. coli and its phages and plasmids. The techniques of genetics and biochemistry have been used to identify genes and their products (proteins) involved in DNA replication (Table 26.3). The most extensively studied examples include DNA replication from (i) E. coli chromosomal origin oriC; (ii) phage replication origin, oriλ; (iii) phage PI lysogenic origin oriP1; and (iv) ColE1 and pBR322 plasmid origin. Among these four systems, more variation is found in the initiation than in the elongation and termination of DNA replication.