DNA synthesis is automated. e8n8oweb6desaeaouessmiertothoaeused 。 agsEwa8aaadmetonmnom ORGRENRCR-S0O (PCR)makes The process involves anagttos4n he DNA 2e2sawe 11 11 DNA synthesis is automated. DNA can be synthesized using techniques similar to those used in the Merrifield polypeptide synthesis. The bases cytosine, adenine and guanine require protection at their amino functions: The deoxyribose is blocked at C5’ as a dimethoxytrityl (DMT) ether, readily cleaved by mild acid. The first protected nucleotide is anchored to a surface￾functionalized silica (SiO2), bearing an amino substituent as a “hook”, using an activated linker, a diester. The polymerase chain reaction (PCR) makes multiple copies of DNA. The polymerase chain reaction (PCR) allows the reproduction of DNA segments in vitro by the millions, without the necessity of living cells. The process involves: •Heating the reaction mixture to 90-95oC to separate the double stranded DNA into two complementary strands; •Cooling it to 54oC to allow primers to attach to the DNA strands; •Heating to 72oC to allow a DNA polymerase (Taq, stable at high temperatures) to produce a completed copies of the DNA strands. This process is repeated over and over, each time multiplying by two the number of completed double-stranded DNA molecules present