DNA isolated from heat-killed S cells can also cause virulent S colonies to appear after mixing with R cells and plating. Enzymes vary in their ability to prevent S colony formation. The conversion of organisms of one phenotype to another by incubation with non-living material is known as transformation . The ability to transform organisms with extracted DNA is important to the molecular analysis of chromosomes. These experiments are recognized as the first in a series that lead to the conclusion that DNA is the carrier of genetic information, the genetic material.
Genetic transformation is one of several tools in bacterial genetics.
Pneumococcal cells are only competent to take up DNA for a brief time after they reach a certain density of cell growth.