Gene synthesis refers to the standardized synthesis of DNA molecules with double strands in vitro through the manual method, the most basic technological means in molecular biology research. When compared with traditional molecular cloning technique, artificial gene synthesis relies on the chemical method to compound DNA sequences without a template. This method allows the sequence to be natural or edited. DNA synthetic technology, which can compound DNA sequence with high efficiency at low cost, subverts biology research methods. With the improvement of gene synthesis abilities, people are no longer satisfied with compounding single genes. They are more willing to compound complicated living systems; as a result, the research direction has changed from “part” to “whole”. From gene circuits and metabolic pathways to synthetic mini gene groups and even artificial life, gene synthesis is being applied almost everywhere. The length and difficulties of compound sequences are both also increasing constantly. For example, Gibson completed trace-less linker of DNA fragments by artificial synthesis in 2010, compounding 1.08Mb-long mycoplasma mycoides; Itaya cloned 3.5 Mb-long synechocystis PCC6803 to bacilus subtills genome by interative replaced method until it became the 7.7 Mb fusion genome.
In recent years, the advancement of DNA synthetic technology and the semiconductor chip manufacturing process has not only decreased the cost of DNA synthesis sharply, but also has improved the flux of gene synthesis, meaning that gene synthesis can be applied in more and more fields, such as biological medicine, molecular diagnosis, enzyme engineering and industrial enzymes, bioenergy, food and modern agriculture, environmental protection and monitoring, DNA storage and development, etc. With the synthesis of virus, whole genome of prokaryotes are now compoundable by chemistry, putting human genome programming on the agenda. In this plan, scientists are trying to change genomic coding to solve human health issues, providing new therapeutic opportunities for disease management and developing more efficient pharmaceutical medicine.