In order to understand the function of genes, transfection can be used as a method in which artificially prepared knockout and expression constructs are being introduced into cell lines. Since many genes are essential for embryonic development and a homozygous deletion results in non-viable embryos, gene disruption in a cell line by using transfected constructs might be an alternative choice. Electroporation is often used to stably transfect knockout and knockin vectors into DT40 cell line.