Definition and meaning of recombinant DNA

Summary

Recombinant DNA (rDNA) refers to DNA molecules created by laboratory methods of genetic recombination, such as molecular cloning, that combine genetic material from multiple sources into sequences that would not otherwise occur 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 or even by inserting DNA sequences that do not exist in nature (via chemical synthesis). Recombinant DNA is often described as “chimeric” because it can contain segments from different organisms. In rDNA technology, foreign DNA is inserted into a vector (commonly derived from plasmids or viruses) and introduced into a host cell. The resulting construct may be replicated without producing a protein, or it may be transcribed and translated to generate recombinant proteins, depending on whether the DNA is properly configured with expression elements such as promoters and other regulatory signals. Recombinant DNA differs from natural genetic recombination because it is produced by artificial, controlled methods rather than normal biological processes.

Key Points

• 1

  Recombinant DNA is artificially constructed by combining DNA fragments from different sources to form novel sequences.

• 2

  It is possible because DNA molecules share a common chemical structure across organisms, differing mainly in nucleotide sequence.

• 3

  Recombinant DNA is typically built using a cloning vector and introduced into a host cell; it may or may not be expressed.

• 4

  When expressed, recombinant DNA can produce recombinant proteins, but expression often requires specialized expression vectors and gene restructuring.