Definition and origin of recombinant DNA

Summary

Recombinant DNA (rDNA) refers to DNA molecules created by artificial laboratory methods of genetic recombination, such as molecular cloning, that combine genetic material from multiple sources to form sequences not normally found together in an organism’s genome. Because DNA from all organisms shares the same chemical structure, recombinant DNA is possible by joining fragments from different species (e.g., plant DNA with bacterial DNA, or human DNA with fungal DNA). rDNA is sometimes described as “chimeric” DNA because it can contain segments originating from different organisms. The origin of recombinant DNA lies in the development of laboratory techniques that cut, join, and replicate DNA fragments. rDNA technology relies on DNA being engineered into vectors (often plasmids or viruses) and assembled using methods such as restriction enzyme/ligase cloning or Gibson assembly. DNA fragments can also be created by chemical synthesis and incorporated into recombinant constructs, enabling essentially any DNA sequence to be built and introduced into living cells. The concept was first proposed in the early 1970s, with key experimental reports of successful production and intracellular replication appearing in 1972–1973, followed by major advances in the 1970s and early 1980s that helped establish recombinant DNA as a practical biotechnology.

Key Points

• 1

  Recombinant DNA is artificially constructed DNA that combines fragments from different sources to create novel sequences.

• 2

  It is possible because DNA from all organisms has the same chemical structure, differing mainly in nucleotide sequence.

• 3

  rDNA is built using cloning vectors and DNA assembly methods (e.g., restriction/ligase cloning or Gibson assembly), and can also include chemically synthesized sequences.

• 4

  The idea and early experimental demonstrations of recombinant DNA emerged in the early 1970s, leading to major scientific and technological milestones in the following decade.