Introduction - Transformation Methods
Transformation is the process of genetically changing a living thing. A genetically engineered plant has been transformed and is sometimes referred to as a transgenic plant. In order to make and identify a transgenic plant that will pass the new gene on to its offspring, the following must happen.
- Many copies of the new gene (transgene) must be placed into the nucleus of the plant cell without killing the cell.
- At least one copy of the transgene must insert into the chromosome of the plant cell.
- The transformed cell must replicate its chromosomes, including the new gene, and then divide. The division process must be repeated until the transformed cell develops into an entire transgenic plant.
- This transformed plant must have some characteristic that makes it easy to distinguish as a transgenic plant. This could be a selectable marker gene.
The goal of any transformation technique is to transport the new gene and usually a selectable marker gene into the nucleus of a cell without destroying it. After that, the genetic engineer has no control as to how or even if the gene will insert into a chromosome. The successful genetic engineer plays the numbers game. Because they cannot control all of the steps, they repeat the process hundreds of times in order to produce one genetically engineered plant.
Many methods of delivering extra DNA into the nucleus of plant cells have been tried, and several have been successfully used to produce a transgenic plant. The most common methods will be described in this lesson.