Recombination

Rearrangement of genetic material

Rearrangement within DNA molecules is a natural, random process. It is the source of much of the genetic variability that drives evolution.

Several known processes cause genetic recombinations:

• Homologous recombination: Chromosomes or DNA segments with identical or similar regions can recombine and switch places. This naturally occurs during meiosis.
  
• Non-homologous recombination: Occurs when dissimilar DNA fragments are integrated into a chromosome e.g. "jumping genes" (transposons)

Genetic engineering involves precisely directed genetic recombinations. Desired DNA sequences are cut out, usually with the help of restriction enzymes, and fused to other pieces of DNA. Artificially constructed DNA molecules are referred to as "recombinant DNA". The resulting proteins can be called "recombinant proteins".