Transformation Is DNA-Mediated

Griffith s result was duplicated outside of the animal by Dawson and Sia in 1930. Both bacterial strains were grown in liquid growth medium and distinguished by the distinctive appearance of their colonies on plates (see fig. 25.1ft). In parallel with the results obtained in the mouse, 

Avery s experiments on cells were followed by additional experiments on viruses, demonstrating that the genetic information of a virus is carried by nucleic acids. In the case of a cell the genetic information is always carried by DNA. In the case of viruses the genetic information can be carried by either DNA or RNA, depending on the virus. 

The early work equating genetic material with DNA plunged genetics into an entirely new vocabulary of chemical terms. The genetic consequences of these early studies 

In vivo and in vitro evidence that DNA causes transformation of Streptococcus pneumoniae, (a) Transformation experiment by Griffith. R bacteria are nonvirulent. S bacteria are virulent. A mixture of R bacteria and heat-killed S bacteria is also virulent if transformation has occurred. (b) Transformation experiment by Avery and coworkers. When bacteria from a liquid culture are spread on a semisolid medium, each cell adheres to the medium at random. As 

In addition to the main DNA associated with the cell or the virus, informational DNA is found in special organelles, such as chloroplasts and mitochondria. This DNA carries genes whose products are exclusively associated with organelle function. 

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The Genetic Significance of Nucleic Acids Transformation Is DNA-Mediated Structural Properties of DNA... 

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