The direct uptake of foreign genetic material by cells and incorporation into the cells’ genome.

An evolutionary event involving the transfer of genes, from one species to another, in which the viable offspring gain genetic diversity.

Horizontal gene transfer (HGT), also Lateral gene transfer (LGT), is any process in which an organism transfers genetic material to another cell that is not its offspring. By contrast, vertical transfer occurs when an organism receives genetic material from its ancestor, e.g. its parent or a species from which it evolved. Most thinking in genetics has focussed on the more prevalent vertical transfer, but there is a recent awareness that horizontal gene transfer is a significant phenomenon.