Genetic engineering, also called
genetic modification, is the direct manipulation of an organism's
genome using
biotechnology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel
organisms. New
DNA may be inserted in the host genome by first isolating and copying the genetic material of interest using
molecular cloning methods to generate a DNA sequence, or by synthesizing the DNA, and then inserting this construct into the host organism.
Genes may be removed, or "knocked out", using a
nuclease.
Gene targeting is a different technique that uses
homologous recombination to change an endogenous gene, and can be used to delete a gene, remove
exons, add a gene, or introduce
point mutations.