Genetic information can be transferred from one cell to another naturally by sexual reproduction in which genetic information is transferred from a sperm cell to an egg cell during fertilisation.

Some bacterial species can transfer plasmids between them naturally. Viruses carry genetic information into the cells of other species.

It has also been found out that genetic information can be transferred artificially from cells of one species to the cells of another completely different species using genetic engineering.

Human genes have been transferred to bacteria so that the fast-growing and rapidly reproducing bacteria make proteins that are required medically. One example involves locating the gene that codes for the protein insulin on a human chromosome and then transferring it to a bacterial species that can be cultured rapidly to produce large amounts of insulin required to treat diabetics.