What is the name of the process by which bacteria acquire genes from their environment?

The process by which bacteria acquire genes from their environment is called transformation. In this form of horizontal gene transfer, a competent bacterial cell takes up free DNA released into its surroundings and may incorporate it into its own chromosome.

Transformation differs from the other two classic forms of bacterial gene transfer. In transduction, a bacteriophage carries DNA between bacteria; in conjugation, DNA passes directly between cells, often through a pilus. Transformation requires no living donor cell, only accessible extracellular genetic material and a recipient capable of taking it up.

The idea was revealed by Frederick Griffith in 1928 while studying Streptococcus pneumoniae. Later, in 1944, Oswald Avery, Colin MacLeod, and Maclyn McCarty showed that DNA—not protein—was the “transforming principle.” Some bacteria enter a temporary physiological state called competence, often triggered by crowding, starvation, or DNA damage. Transformation can spread useful traits, including antibiotic resistance, but it may also help bacteria repair damaged DNA.