The introduction of DNA into a recipient eukaryote cell and its subsequent integration into the recipient cell\'s chromosomal DNA. Usually accomplished using DNA precipitated with calcium ions though a variety of other methods can be used (eg. electroporation). Only about 1% of cultured cells are normally transfected. Transfection is analogous to bacterial transformation but in eukaryotes transformation is used to describe the changes in cultured cells caused by tumour viruses. Though originally used to describe the situation in which the transfected DNA is integrated, it is now frequently used just to mean introduction of DNA into a target cell, hence the necessity to specify stable transfection.
Dictionary of molecular biology. 2004.