Genetic engineering is the process of altering the DNA of an organism in order to change its traits. This can be done by inserting new genes into the organism's genome, deleting existing genes, or changing the sequence of genes. Genetic engineering has a wide range of applications, including the production of genetically modified crops, the development of new drugs and vaccines, and the study of human genetics.

Recombinant DNA technology is a key tool used in genetic engineering. Recombinant DNA is created by combining DNA from two different sources. This can be done by cutting and pasting DNA fragments together using restriction enzymes and DNA ligase, or by using a polymerase chain reaction (PCR) to amplify a specific DNA sequence.

The first recombinant DNA molecule was created in 1973 by Stanley Cohen and Herbert Boyer. This breakthrough paved the way for the development of genetic engineering and its many applications.