by Adam Canal
Graduate Research Assistant, Agriculture Editor
Step by Step of the Trangenics Process:
- The desired transgene is identified in another (or the same) species.
- There is extensive experimentation on the gene, so that scientists can learn as much as they can about the sequence and the protein it produces.
- The gene of interest is combined with the necessary genetic machinery like promoters and terminators (these signal the start and stop of the DNA sequence). This new mashup is called a cassette.
- The cassette is then loaded into the plasmid and the plasmid is then taken up into a special, nonvirulent strain of Agro.
- Agro is then introduced to each of the lines.
- Agro interacts with the plant cells and injects the plasmid into the host cell.
- That plasmid is then hopefully incorporated into the plant DNA. Most likely the plasmid will be degraded, chaperoned elsewhere, inserted in backwards, etc. This is where most of the events fail.
- Each of the lines must be grown out in tissue culture and screened for the presence of the plasmid DNA and whether it’s in a neutral place in the plant chromosomes. The plasmid could very well be inserted into something really important, like an enzyme that makes chlorophyll.
- Plants that are plasmid absent or have deleterious effects from the transformation are discarded.
- Selected lines are then crossed into elite lines (lines that have superior yield and aesthetics) and then genetically stabilized with many generations self-fertilization.