Gene synthesis is a piece of DNA engineered in the laboratory. The cell's machinery recognizes the new DNA as being artificial and doesn't try to replicate it with its natural replication process. It makes it possible to create DNA sequences that would not occur naturally in nature or would only rarely occur by chance. Recombinant DNA molecules are developed by joining two or more pieces of different lengths.
Gene synthesis is used in developing synthetic biology and genetic engineering methods. It has also been used to develop treatments for cancer, hemophilia, and other diseases.
Gene synthesis is now widely used, with more than 25 000 synthetic genes in patients as of 2009, according to the International Nucleotide Sequence Database Collaboration. These include tumor suppressor genes for cervical cancer, Factor IX for treatment of hemophilia B, and other genes for leukemia and breast cancer.
The first gene synthesized was insulin in 1979 by Robert Holley and coworkers at the University of California, San Francisco, who identified a sequence that could be inserted into a bacterium to produce human insulin. The code they came up with was published in Science later that year. The same team of researchers, led by Andrew Fire and Craig Mello, then developed methods for inserting the new DNA into a chromosome in a roundworm. The technique was subsequently adapted for humans, with a patient receiving the first such treatment in 1990.
Gene synthesis is used in developing new pharmaceutical drugs to treat diseases. In 2006, Novartis patented a process that allows it to use gene synthesis to add new genes to cells so they can produce drugs on their own. One benefit of this process is that it can make organisms generate drugs that the organisms themselves would never have made naturally.
In 2005, researchers at the Institute of Genetics and Development in Moscow created gene synthesis obstacles. They engineered a virus that would not act independently but only when it infected a cell. The process allowed the researchers to use RNA cells instead of genetic material.