What are gene guns and bombardment methods?

Expert response from Jennifer Hanks

Research Scientist and Laboratory Leader, DuPont Pioneer

Tuesday, 17/05/2016 11:08

The gene gun was invented between 1983 and 1986 by researchers at Cornell University and DuPont. Originally, it was used to fire particles, coated with DNA, into plant cells. As pictured in the diagram, the particles are coated and placed on a plastic disc, which is fired out of the gene gun at rapid speed. The disc is stopped by a screen, allowing only the DNA-coated particles to travel through and into cells contained on a plate below. 

This process is known as transformation, and is one of the ways that researchers perform genetic modification in plants. The technology has changed over time and now gold or silver particles are used instead of the original steel particles, but overall the process has remained largely unchanged. 

 

After impact from the particles, most of the plant cells are destroyed; however, the remaining intact cells now contain a DNA-coated particle. The DNA on that particle eventually makes its way to the nucleus of the plant cell and is integrated into the plant’s existing chromosomes (DNA). Researchers then transfer the tissues from the impact plate to plates where they can grow into a plant that contains the target DNA. If the plant is grown and pollinated, the progeny will also contain the target DNA sequence introduced through the gene gun.

The technology has revolutionized our ability to perform transformation in plants, especially in those resistant to other methods of transformation (i.e., rice, wheat, millet and maize). However, it does have limitations. The insertion of the target DNA into the plant chromosome is random. The researcher has no control over where or how many insertions occur in the plant’s DNA. In this case, both the location and number of target sequences inserted will be determined during the evaluation of the transgenic plant.