Answer:
Gene transfer refers to the movement of genetic information between organisms. Vertical gene transfer passes genes from parent to offspring.
Lateral gene transfer passes genes to other cells in the same generation. It occurs in bacteria by transformation, transduction, and conjugation.
Bacterial transformation was discovered in 1928 by Griffith, who showed that a mixed culture of live rough and heat-killed smooth pneumococci could produce live smooth pneumococci capable of killing mice. (Black)
How could dead bacteria give genes to the live bacteria?
The dead one left DNA behind which was picked up by the alive bacteria, changing it so that it could kill.