Gene synthesis is creating a DNA sequence de novo or assembling fragments of sequences to make a complete, functional gene. In synthetic biology, DNA and proteins are typically created in test tubes using chemical reactions called polymerase chain reaction and reverse transcription, respectively. However, creating DNA molecules de novo from simpler chemical building blocks is possible.
The technique relies on chemists’ ability to build complex structures out of simple building blocks like nucleotides. Gene synthesis is also used in some genome editing techniques, such as CRISPR. Creating a DNA molecule is easy. The challenge is to create the DNA sequence that encodes the desired target product in its correct order and to insert the correct stop codon for termination.
In its simplest form, synthetic biology uses two technologies: chemically synthesized oligonucleotides and transcription by reverse transcription. Both provide ways to build a DNA molecule from simple building blocks. Microbiology tests these technologies in the lab, so scientists know how to do it.
A significant application of gene synthesis is the development of new drugs and diagnostics. Currently, many novel anti-cancer drugs or targeted gene therapies are being developed based on synthetic biology research. This technology has also helped create new antibiotics by constructing DNA molecules that target bacterial proteins to disrupt their function. In 2010, researchers even created a gene designed to cause white blood cells to remove fat cells from cancer patients. Gene synthesis has been used to develop new tools for diagnosis, such as a fetal DNA test that can be performed on a pregnant woman’s blood.
Gene synthesis also allows researchers to develop cheaper alternatives to biologics like monoclonal antibodies and vaccines. Using the synthetic biology platform, researchers have developed a recombinant vaccine against meningitis that is more effective than current vaccines and could potentially replace the need for booster shots. The synthetic biology platform will allow researchers to target many different kinds of diseases using new gene therapies that one can rapidly produce at a lower cost. Gene synthesis also has an essential role in agriculture: it increases crop yields by producing plants resistant to pests and herbicides, leading to increased food security.