DNA Synthesis in Vivo and in Vitro
Replication copies the entire set of genomic DNA, so that the cell can divide in two. During replication, the entire genome must be uncoiled and copied exactly. This elegant process occurs extremely fast in E. coli, where DNA polymerase copies about 1000 nucleotides per second. Although the process is slower in eukaryotes, DNA polymerase still copies 50 nucleotides per second. Many biotechnology applications use the principles and ideas behind replication; therefore, this chapter first introduces the basics of DNA replication as it occurs in the cell. We then review some of the most widely used techniques in genetic engineering and biotechnology that rely on DNA polymerase, including chemical synthesis of DNA, polymerase chain reaction, and DNA sequencing.