The Beginning

In 1973, the first organisms possessing recombinant DNA fragments were produced. Stanley Cohen from Stanford, Herbert Boyer from the University of California, and their colleagues inserted a piece of DNA from one plasmid (DNA molecule separate from the chromosomes, often found in bacteria) into another, creating an entirely new, recombinant DNA molecule.

Not long after that, they were able to transfer genes from a frog into a bacterium, creating what is known as a chimaera, or hybrid DNA molecule. These experiments led to the development of the techniques now used in recombinant DNA technology.

This recombinant DNA technology is a set of molecular techniques to locate, isolate, alter and study DNA segments. It is commonly referred to as genetic engineering.

Impact

Recombinant DNA technology has dramatically altered the way in which genes are studied. Previously, information about the structure and function of genes was gained by examining their phenotypic effects, but this new technology made it possible to just take a look at the DNA sequence itself.

The technology has provided new information about the structure and function of genes and has changed many fundamental concepts of genetics. For example, it was previously though that the genetic code was completely universal, but now it is known that non-universal codons exist in mitochondrial DNA.

It has increased our knowledge about important processes such as replication, transcription, translation, RNA processing and gene regulation greatly. The techniques are used in numerous fields, such as biochemistry, microbiology, developmental biology, neurobiology, evolution and ecology.

The Commercial Aspect

Recombinant DNA technology is also used in the development of several commercial products, including drugs, hormones, enzymes and crops. An entirely new industry, biotechnology, has arisen through the use of this set of techniques in the development of new products.

In medicine, recombinant DNA technology is used to probe the nature of cancer, diagnose genetic and infectious diseases, produce drugs and treat hereditary disorders.

Five Basic Techniques

The techniques used in recombinant DNA technology are very diverse, yet one can divide into five basic concepts that constitute the largest part of the array of techniques used:

• Methods to locate specific DNA sequences.
• Techniques to cut DNA sequences at specific locations.
• Procedures to amplify a certain DNA sequence billions of times, producing enough copies to carry out further mutations.
• Methods to mutate and join DNA fragments to produce the desired sequences.
• Procedures to transfer DNA sequences into recipient cells.