Biology: horizontal gene transfer: transformation

Tutoring biology, one encounters surprising concepts. The tutor mentions transformation.

Horizontal gene transfer refers to the concept that one single-celled organism can receive DNA from another unrelated one. I’ve seldom heard it mentioned but it’s a thing. One way it’s accomplished is called transformation.

A transformation scenario might occur as follows: a dead bacterium’s DNA is decomposing into fragments. One such fragment makes contact with a “competent” living bacterium. “Competent” means the bacterium is able to bring in that foreign DNA fragment, replace its corresponding DNA sequence with the foreign fragment, and then loose its replaced fragment back into the environment. Theoretically, its loosed fragment may end up back with the rest of the DNA from the dead bacterium.

Some bacteria will commit autolysis (kill themselves) in order to donate their DNA for transformation. Moreover, some bacteria will kill others to cause their DNA to be available for uptake via transformation.

As I understand, transformation usually involves two members of the same species, but perhaps not always.

Source:

bio.libretexts.org

ncbi.nlm.nih.gov